Heatsinks are falling off in 6400 and 6600 models.

  • 4
  • Problem
  • Updated 1 year ago
  • In Progress
As part of the Product Enhancement Notification (PEN) or Recall.  If you want to know where to look to
see if both of your heatsinks are in place and have not fallen off.  Here are some photos to look at.
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Tom Teague

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Posted 1 year ago

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Gordon, ve7on

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Would it not be better to leave both heat sinks on with a cable tie around the board for security?

I would think the cooling would be improved.
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Wim

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Good idea Gordon, I think I will do it like that
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Wayne

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The first 4 pictures are before pictures when I opened the 6400M The next 2 pictures are after I attached the wiretie one of the board and the 2nd of the board after it was plugged back in. The last picture just one of my latest tcl 43" 4k hd monitor above the rig in the shack. There is only 1 adc heatsink in the 6400M since there is only 1 adc board and 1 scu.
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Robert Lonn

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I have a Fluke Thermal Imaging Camera,  So I hope to open it up and take a picture of these Chips to see how they are doing with the revised heat sink design...

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mikeatthebeach .

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Like to see what the top of the A/D chip temp is in deg C is with and without 
backside heatsink to really see if PEN heatsink thru the PCB high
thermal resistance is really effective 

Hope the MTBF is not affected, in Semi-World Reliability Talk, every 10deg C
rise above SOA temp can cut MTBF hours in half in GaAs & GaN, not sure 
what it is in Silicon.

A big concern is that the BGA for the A/D chips  is subjected to more Temperature swings between on & off cycles to be a reliability MTBF issue if Temp is not carefully controlled within the SOA specifications of the A/D
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Gerald - K5SDR, Employee

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The back of the board is a much better thermal sink that the chip top, which is plastic.  The chip is designed to sink through a thermal pad to the ground plane under the part.  The bottom of the board is solid ground plane.  We measure the results with an infrared thermal camera.
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Bill -VA3WTB

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These chips work just fine without any cooling at all, no harm will come to them. in many cases in their applications a heat sink is not used as they do not get very warm, never hot.

When they are used in a Flex radio, they are used in a very sensitive application.
The only reason Flex uses heat sinks is for the needs of the radio. It must stay under a certain temp to allow the best performance of the radio. any cooler temp other than the target running temp has little to no benefit. So it has been determined that the corrective action allows for much more cooling then needed.
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Wayne

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Ok if that is true Bill then why is flex providing a larger heatsink in the PEN kits following what you are saying indicates the performance of my rig will be negatively affected by installing the larger heat sink. Now Im getting confused with conflicting information from flex and yourself, someone official from flex needs to provide the real explanation.
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Bill -VA3WTB

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I did not say that a larger heat sink would be negative. I said running cooler then what is need heads little value. So the fix they have is more then is needed for top performance.
(Edited)
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Wayne

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Sorry Bill thats what old age seems to bring I sometimes see more or less than what is actually said when I see words between the lines ... hi hi
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Bill -VA3WTB

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Me too, I have to read things over and over sometimes..lol
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Jon - KF2E

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When the heatsink fell off of mine the radio went deaf. S9+10 noise across the whole band. I was skeptical of the new heatsink fixing the issue, especially with the new one being on the back of the board with the board between it and the chip. After all, how good of a conductor is a fiberglass board? That said, with the new heatsinks in place it seems to be working.
(Edited)
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Gerald - K5SDR, Employee

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The back of the board is a much better thermal sink that the chip top, which is plastic.  The chip is designed to sink through a thermal pad to the ground plane under the part.  The bottom of the board is solid ground plane.  We measure the results with an infrared thermal camera.
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Rick WN2C

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What I don't understand is why Flex didn't just send out some heat sink compound to re=attach the original heat sink. How does putting a heat sink on the bottom of the board better than on top of the chip? 
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Bill -VA3WTB

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The epoxy is on the heat sink that is sent out, it is already applied.
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Gerald - K5SDR, Employee

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The back of the board is a much better thermal sink that the chip top, which is plastic.  The chip is designed to sink through a thermal pad to the ground plane under the part.  The bottom of the board is solid ground plane.  We measure the results with an infrared thermal camera.
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Robert Lonn

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At some point in time you have to place your trust in the Engineers at Flex.. They decided to do it this way for many reasons I am sure. Some are engineering, some at Business decisions and some are customer service related.. I think what is worth mentioning is that Flex has responded FAST to this problem,, And they are taking care of it for their customers..

As many of you have read, Heat Sink are falling off on the new Icom IC-7610 radio... Lets see how Icom responds to this.. They are just now beginning to gather serial numbers of the affected radios,, However only those who read the blog will even know about it,, I am sure their are hundreds if not thousands world wide who have no idea what is going on..

Flex notified all its customers , all of them and that is what first class customer service is.. My experience with Yaesu, Icom and Kenwood, is they do not do recalls or send out TSP by email.. If someone reports an issue, and it is under warranty, they just respond by telling the customer to send it to the repair center... But it is the Customer, not ICOM who must be proactive! 

Robert
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Bill Roberts

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I agree 110%.  The purpose of this forum is not just to heap praise on FRS.  Yet, in 54 years of hamming, I have never seen a company that works so hard to help their customers happy and successful... not even Heathkit.  
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FRED W9TB

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Robert, Flex did not notify all that needed the pen . I know 4 people that got there radios before April, 12 and only one got the pen e-mail. 
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Gerald - K5SDR, Employee

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Fred,
We emailed everyone to whom we shipped radios before April 12 so if they did not receive the email it is probably in their spam folder.  I can assure you that our intent was to notify everyone.
Gerald
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Juan TG9AJR

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I did received the PEN email and answer the survey, now just waiting, unfortunately it did happened in the meantime but team is answering, thanks !
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Rick WN2C

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I agree that FRS is hands down the best at customer service and responsiveness to customers. I have never seen a company do what Flex has done in sending out a product enhancement notice, give you the consumer the option of how it is going to be taken care of and pay for the shipping both ways too boot! I mean who does that? 
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Juan TG9AJR

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A picture is worth a thousand words !So here it is my 6600.

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Gerald - K5SDR, Employee

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You can tie wrap them back on until you receive the replacements.
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Juan TG9AJR

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Did one, will re-align and do the second one, thanks.
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Bill -VA3WTB

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The other on is falling off as well, remember you can put a tiny bit of heat sink compound on them and put them back on with plastic tie wraps till you new parts come in.
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Gerald - K5SDR, Employee

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Heat sink compound is not recommended.  Just tie wrap them back on until the new parts arrive.
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KC2QMA_John

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Can the heatsinks cause a short if they land on the circuit board below while the power is on?

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Gerald - K5SDR, Employee

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It is possible but there is not much exposed circuitry below the parts.
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Wayne

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The biggest danger I see is if the heatsink when it falls shorts out the exposed connections of which there are many where the board plugs into the main board, one picture showed the fallen heat sink very close to those connections.
(Edited)
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KC2QMA_John

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Gerald, I want to thank for being so honest with us on this small problem. I can’t begin to tell you how much it means to me that you have been honest with your customers on this issue many other manufactures would have tried to cover something like this up. To me this says a lot on how you stand behind your product.

BTW when I looked inside my radio to see if my heatsinks fell off, they were still on. But what I did notice is the quality of circuit boards that are used in the radio are Top Notch, Heavy gauge and lots of ground plane. I also noticed the quality of the case itself, well designed with good airflow.

Again thank you

John

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Jay / NO5J

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So, as a possible workaround, pickup your Flexradio, Shake it violently, do you hear any loose parts rattling around? if so open the radio's case and remove the loose parts, and then immediately submit a help desk ticket to find out what to do next.

If nothing rattles, then while shaking the rig, slam it hard into a solid object, like your desktop, until something does rattle, then immediately submit a help desk ticket reporting what you did, and then wait for the reply you will probably get, informing you about the premature expiration of your repair warranty.

or ...

If instead, you hear no rattling, and don't see any signs of any other hardware malfunctions, be Happy!!

You can skip the help desk ticket submission, like usual.

And in the future try to avoid fantasizing about problems your not actually experiencing.

Enjoying your Flexradio, might be easier than you think it is.

#FlexRadio IRC chat

   73, Jay - NO5J

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Bill -VA3WTB

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Yes it is possible, that is one of the dangers.
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Bill-N6RV

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First, I amazed that the first heat sink is glued onto the chip. How about a compression mount with thermal grease? The board should be redesigned and they should recall the radios and replace the boards. You do not know the thermal impedance of the PC board material and there are not enough via holes to make much of difference in the total thermal impedance. It probably is so high that the heat sink on the back is ineffective. The device temperature will rise to an unacceptable level. It will not shed the heat. Consider amplifier chips that are mounted on a bar and then mounted on a heat spreader. That is good thermal design. Also consider computer chips. The heat sink is integral to the chip not glued on.

An acceptable level is a level where, when at the top of the specified outside operating temperature, at end of life, the A/D performance does not degrade the sensitivity. Right now I am looking at both antenna ports (Ant 1 & Ant 2) of my 6600M and there is a 35dB difference in the noise in a 500Hz bandwidth measured with the S meter dBm level, with no antenna connected! The heat sink on antenna 1 has fallen off and the A/D has degraded the performance by 35dB! Has the chip been damaged by the temperature rise. It must be to have degraded the performance by 35 dB!

If you have a noise floor problem check one antenna input against the other. If there is a difference it is the heat sink!!!! Even if the heat sink has not fallen off it may be loose and you will see a difference in noise floors.  Comment on this post with your findings. It will be interesting what the differences between the two antenna ports are.
(Edited)
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Bill -VA3WTB

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These chips will not damage without a heat sink. In many other devices were they are used the heat sinks are commonly left off.

Only that these chips are used in the Flex in a very sensitive place they need to run at a target temp in order to perform at their best when used in the radio for this application.

If the correct epoxy was used from the start none of this conversation would have happened.

Because it has happened, some are suggesting that Flex engineers do not know what they are doing.

The mounting of these chips are a common practice in the electronics industry more and more.

In the way Flex has decided to mount the the new heat sinks on the back is perfectly fine. The cooling is not dependent on holes on the board. The heat from the chip is picked up from the pin connections on the back of the chip.

These chips do not get very warm, It does not take very much to cool them.
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Wayne

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I would think it would not be unreasonable if your rig was affected already by the heatsink coming off to expect that the adc boards would be totally replaced with new modified adc boards off the assembly line to assure reliability and a normal mtbf and life of the adcs. Any electronic component which has been overheated should not be reused to ensure mtbf. When yaesu had the 991a finals issue not only did they replace them but they now give a 3 year warranty on the 991's.

Those rigs that have not been affected yet should be fine by just having the modification kits done. Im so glad I checked mine and found it attached still and used a wire tie to securely hold it in place.
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Wayne

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Bill if the heatsinks for the chips are left off for so many other applications I dont understand why they are so necessary and if they are so necesary then its more than prudent to say the chips when heated must have been affected or damaged if the symptoms we are seeing cause the radio to go deaf. Its kinda like overheating your engine and causing the block to crack after it cools down the engine will still run buts its no longer reliable with the white smoke coming out. Of course the adcs dont have smoke coming out but there is no way to determine the internal damage thats been done to the adc by being overheated.
(Edited)
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Bill -VA3WTB

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In most industry applications were they are used, the running temp is not critical as long as they work.

But in the case of how Flex uses them they have to be kept at a target temp in order to perform as Flex needs them to.

The ADC circuit is very temp sensitive in the Flex.

Gerald mention the other day that the lack of a heat sink will not damage the chip.
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Jon - KF2E

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Bill, I'm curious what your background is that you are an authority on heat dissipation and it's affect on the ADC.
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Wayne

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Ok Bill, I will not respond to this post further since there is nothing I have to add that would be positive. Thanks for the reply.
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Bill -VA3WTB

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I spent several hours tracking down, this ADC chip and found it used in the electronics industry, there locations, needs. and mounting. thermal needs.

Most of what I said are also things mentioned from Flex, read carefully.

Gerald said, these chips get warm, but will never damage without a heat sink.
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Wayne

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Thanks for your reasearch Bill.
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Bill -VA3WTB

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Wish I was an expert, but I'm not, I am trying to share what I know, and I trust the engineers at flex to do what works best, they have a lot of skin in the game so to just throw something out there hopping it works?. They are very good at what they do, in my opinion.
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Gerald - K5SDR, Employee

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The back of the board is a much better thermal sink that the chip top, which is plastic.  The chip is designed to sink through a thermal pad to the ground plane under the part.  The bottom of the board is solid ground plane.  We measure the results with an infrared thermal camera.
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Bob Young

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If the back of the board is a much better thermal sink, then why did you place the heat sink on the top of the chip in the first place? 
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Bob Young

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If the back of the board is a much better thermal sink, then why did you place the heat sink on the top of the chip in the first place? 
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Bill-N6RV

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Hold on!!! The heat sink you suggest is now pinned between the board and the partition. Are you relying on convection alone to move the air across the heat sink. The fan is in the other compartment blowing air over the power amplifier. How does a heat sink work inside a confined space like that?
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Bill -VA3WTB

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It is call Natural convection, in this type of heat transfer the cooling is not done with forced air from a fan. but the air still moves. The air is heated through the cooling fins and rises and picks speed up as it continues to the top of the rows of fins. New cool air rushes in to replace the heated air and the cycle continues.

This is mostly used on applications were temp is important and the source gets warm and never hot.

As mentioned before these chips are not hot, so this form of cooling works well.
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Bill-N6RV

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Here is a snippet from the video you published. Show me the thermal pads and via holes as recommended by the chip manufacturer.


I do not see any. The thermal impedance must be really bad! Combine that with the heat sink stuck between the PCB and a metal partition and the thermal issue is still a concern.
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Bill-N6RV

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Bill- VA3WTB
Are you a thermal engineer? I am not. I did work on satellite hardware at component level, unit level and I oversaw the design of satellite payloads. I also worked on ground based rack mounted comm hardware and hardware that had to survive Aircraft Uninhabited Fighter (AUF) specifications plus I worked on rack mounted satellite special test equipment. I have a healthy respect for thermal design. In all the designs, if the junction temperature of a device exceeds the specified limit, the MTBF of the device is severely degraded. The reliability goes to pot! No telling what happens to the device. The manufacturer specifies a certain temperature range and they do not usually indicate what happens when that range is exceeded. They do not want you to go there!

I think publishing the thermal imaging data will help. But that is the case temperature and there thermal impedance from the case to the junctions hence the junction temperatures will be proportionally higher! A full thermal analysis is required not just tongue in cheek comments.
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Bill -VA3WTB

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I think I have said all I will say. On to other things. And Gerald has answered many questions. I really believe they know their doing.
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Gerald - K5SDR, Employee

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Paul, see my official comments below in this thread.  There are 36 ground vias under the ADC.  The design is exactly as in the datasheet but with 3x more vias than they require.  These connect to two solid ground planes, one of which is the bottom of the board.

Gerald


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Gerald - K5SDR, Employee

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Paul, my bad.  ;>)

FYI, the vias are 8 mil diameter and are all covered by solder mask on the bottom of the board so they are hard to see.  They are bare copper on the chip side of the board.
(Edited)
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Pat N6PAT

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Some points to consider:

Gerald- K5SDR said in reference to putting the new heat sink on the back of the board:


The back of the board is a much better thermal sink that the chip top, which is plastic.  The chip is designed to sink through a thermal pad to the ground plane under the part.  The bottom of the board is solid ground plane.  We measure the results with an infrared thermal camera.

If that is the case then why was it designed with the heat sink on top of the chip in the first place and did the original design result in overheating the components by not providing enough protection?

Also wayne suite brought up a good point:


Bill if the heatsinks for the chips are left off for so many other applications I dont understand why they are so necessary and if they are so necesary then its more than prudent to say the chips when heated must have been affected or damaged if the symptoms we are seeing cause the radio to go deaf. Its kinda like overheating your engine and causing the block to crack after it cools down the engine will still run buts its no longer reliable with the white smoke coming out. Of course the adcs dont have smoke coming out but there is no way to determine the internal damage thats been done to the adc by being overheated.

If the heat sinks are required to avoid damage how can anyone be certain that their radios did not suffer some amount of damage while the heat sink was detached? Many owners say they keep their radios powered up 24/7 so shouldn't they be concerned about possible damage that may have occurred? How long can a radio be powered up safely with the heat sink detached?

Would it be prudent for Flex to replace the boards to ensure that no future problems develop due to any overheating experienced while the heat sink was detached?What is the cost of replacing one of those boards ?

If I owned one of the affected radios I would certainly be requesting new boards.
(Edited)
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Cal Spreitzer

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I'm deeply concerned about the condition of my 6600!  It was put in operation on Feb 21, 2018 and ran 24/7 for eight weeks straight before the  receive went out.  When trouble ticket was submitted I was instructed to send it back to Flex for repair for a known thermal issue with the A-D Converters. This was Apr. 26, 2018 which was before the PEN was announced.   The only repair done was the addition of the new  heat sink which is now a PEN.    The fact that the thermal issue takes out / degrades receive should be enough to effect a chip replacement.   I will have to wait and see how the receive is once I get it back???  It's currently on a brown truck heading my direction.  

Cal/N3CAL
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Gerald - K5SDR, Employee

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See my official comments below.
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KC2QMA_John

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The sky is not falling and it’s not the end of the world. It’s a small problem and so far FRS has addressed it so let’s all take a deep breath and relax it’s technology and humans are not perfect. There are recalls and engineering updates all the time by companies at least in this case it’s not a gas pedal getting stuck or an airbag blowing up in your face.

I am no design engineer but if the new heatsink works well then there is nothing to worry about. From what I can figure the only time the ADC chip temp has the potential to rise out of the safe zone is when the user has the Preamp enabled in SmartSDR (+8, +16, +24 +32dB) because it pushes the chip a bit harder.

As for me I think I will install the new PEN heatsink on the back of the board and clean and re attach the original heatsink to the chip top again using quality thermal adhesive. Then it will be even better cooling. 2 heatsinks are better than 1!

I think a solution that most of could live with is after we all have the PEN update done if within in 2-3 years we start to see numbers of ADC boards failing that FRS will offer free replacement boards.

I’m just glad that FRS did not try to cover this issue up it says a lot about how honest flex is with there customers. Not many companies today are as forthcoming. 


Anyone remember the FT-2000 preamp problem, Yaesu still won't admit there was a problem after all these years.

(Edited)
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N8SDR

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I had one of those turds brand new , 1 month after I had it it went DEAF, sent back for repair, 32 days later it went deaf again, at that point I was really PO'ed having spent $2700 for a new rig and back to them twice within roughly 60 days, while there the second time, I called said I had a job transfer and to ship it to another address, when fixed,  as I had made a deal to trade it to another OP who had a Flex 3000 and wanted a knob radio, that was 9 years ago, and I still have that 3000 that works very well, when I did have questions Flex was very response and helpful, which is way I bought a new 6000 series. Everything by brand Y was removed from shack and will never enter it again. The FT-2000 had a terrible design flaw which if used near or around strong signals would kill the pre-amps in the front end, not to mention nothing on the rear panel was physically grounded to the case, it was all PC board component mounted and that alone was an RF issue. They never reached out to there customers and took care of that issue, instead they blamed them for misuse of the radio.
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Gerald - K5SDR, Employee

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Official Response
Hello all,

Please let me clear up some of the FUD (Fear, Uncertainty, and Doubt).  I designed this part of the radio so you are getting it right from the horses mouth.  That means you can blame it directly on me.  I apologize for any inconvenience you may experience while we do the heat sink replacement.  

Here are the facts regarding the ADC heat sinks:
  1. The AD9467 ADCs do not require heat sinks to safely operate.  We have been using these parts first in government and later in ham applications for 10 years and have never used a heat sink on the parts until the new radios.  That means there are no heat sinks on the 6300/6500/6700 ADCs and they have been in continuous operation since 2013.
  2. The AD9467 has a maximum junction temperature rating of 150 Centigrade (302F).  It is rated  to operate in an ambient temperature of 85 Centigrade (185F).  There is NO risk of damage to the part in your radio with no heat sink.  The PCB is designed to sink the heat into two layers of ground plane through 36 ground vias on the chip's ground pads.  This will keep the chip perfectly safe without an external heat sink.  We will not replace the boards because there is no sound technical case to do so.
  3. The heat sinks were added to increase to increase spurious free dynamic range by a few dB and to hold the clock alignment within a tighter range.
  4. Each time you boot the radio, it does an automatic synchronization of the ADC clock with the FPGA to find the optimal timing.  If the heat sink falls off, the timing of the clock changes and it may lose sync.  This causes the noise floor of the receiver to go up dramatically or you can lose receive all together.  Since the entire system is clocked through the first ADC, it can affect transmit as well.
  5. Simply replacing the heat sink with a tie rap to hold it in place as others have shown here will get you right back in operation if you have not yet received the replacement heat sink kit.
  6. The copper heat sinks we used were selected because they are copper, cost effective, easy to get in volume, and fit the part well.  They were marketed to be used on the Raspberry Pi chip.  Unfortunately, the quality of the thermal adhesive was not what we expected.  
  7. The adhesive problem did not show up on our prototypes or on our our alpha/beta test team until three months after being placed in operation.  
  8. The thermal adhesive on the new heat sinks are rated to require 36 pounds of force at 100C (212F) to remove them after they are properly applied.  
  9. The radios are rated for an ambient temperature in operation of 50C (122F) so I doubt any of you have gotten near the maximum ambient operating temperature of the chip of 85C (185F).  If you have, you are a lot tougher than me.  ;>)
  10. Why didn't I use the heat sink on the bottom to begin with?  Of the thousands of design decisions you get to make in designing a radio, I just didn't think of it.  I had no idea that the adhesive would fail on the one I chose and it was fine thermally to meet the requirement.  I learn something new with each new design.
  11. We have mailed kits to everyone who requested it when we communicated the PEN announcement.  Please complete the survey in the notification if you have not already to receive your kit.
That is the whole story.

Sincerely,
Gerald
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Wayne

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Thank you so much for posting this full explanation, I am sorry that you had to divert your time from more pressing issues, however at the same time I feel that if this explanation was posted initially many concerns would have been satisfied and this particular post would not be going on almost 3 pages now along with other posts relating to it.

From your explanation my only question since you had indicated you was the designer is this: The 6600 then has 2 fpga and adc chips while the 6400 has 1 fpga and agc chip supporting the different speeds listed in the brochure, correct?

Something else I wondered for a while where does one go to learn how to program the complex fpga's is it a factory only school or are courses available in colleges.

Thanks so much Gerald for clearing all of this up once and for all.

Kd5spx in Texas.
(Edited)
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Robert Lonn

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Thanks for explaining this and to Flex for the design enhancement... However ,,,, when I returned from Vacation my mailbox had more Flex Emails about the heat sink then my Spam Folder!! I hope we can finally return to other topics about the Flex Radios and related Software... At Some point in time we should be able to put this to rest...
As a side note, over on the ICOM IC-7610 group as they figure out what to do with heat-sinks falling off, ICOM has already threatened that if you re-attach the heat sink it will VOID your warranty... Flex steps up and fixes the problem, ICOM Threatens its customers!!  Glad I decided back in December to cancel my IC-7610 order with HRO and go with FLEX!!!! 
Robert In San Diego
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KY6LA - Howard, Elmer

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It’s actially worse that that. Icom has not yet acknowledged a problem and it’s only through data collection by Adam Farson who is not an Icom employee that anything is even been noticed.
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mikeatthebeach .

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Icom IC-7610 heatsinks falling off info
http://radioamateur.forumsactifs.com/t2137-icom-ic7610-radiateur-dissipateur-de-chaleur-interne-deco...

Glad I got the Flex6600M instead
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Robert Lonn

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Wayne,, you hit on an interesting point, programming of the internal Chips....  The reason Flex classifies its software as confidential and propriety is that the software written to operate the radio is complex to get optimum performance.. The Software is KEY to overall performance...

Going back to Collins Radios of past,, the engineers at Collins did more then carefully select the TUBES that would go into the radio,,, but also what they did with everything from the Tube Bias, Plate Voltage and even down to Filament voltage.. Most filament voltage is 6.3 volts,, but Collins ran many at 6.1 volts to add in reliability.. That in turn required the Bias and plate voltages to be tweaked to assure they met their design specification.. Sometimes it is a simple thing that can increase performance, and how much of a compromise a design team takes, can be the night and day difference...  Sort of the Monitor DVI output and a somewhat low resolution taken by others, ,VS the HDMI  Full HD output Flex chose to do... 

I think a lot of Hams think that if something is SDR, then it is all a level playing field and all performance is created equal,, so that means that a $200 radio like the SDRplay will outperform every other radio...  Not that the SDR Play isn't a fun device that gives you exposure to a wide band of frequencies as a receive only device,, but it is no better then the FREE software packages that are available, some with support, most with little or no support..

When ICOM sent out an update for my IC-R8600 radio to allow it to be used with the HDSDR software,, I was able to use my RC-28 external tuning know.. However ever since the latest Windows update, the software no longer works with the radio! So we have been told that ICOM and HDSDR are working on a drivers fix!!! I am not holding my breath for a fast resolution,, After all HDSDR is a FREE software package, so where is the incentive to fix anything? I assume that the fix will be available eventually,, Since ICOM claims they support this package for its radio.. It was nice that Flex had the problem identified and a fix within DAYS of the issue coming up...  Again, you get what you pay for...

Robert
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Bill-N6RV

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If I understand what is happening using the heat sink improved the dynamic range slightly but the clock sensitivity to temperature is dramatic causing the noise floor to rise several dB when it falls out of sync.

How sensitive is the clock sync to temperature? Will this become a problem a few years down the road when the thermal efficiency of the heat sink degrades?
Again, if it is clock synchronization, I saw a 35 dB increase in noise floor. How much temperature increase would cause a 10 dB increase?

The ambient temperature is also a factor. If the radio is calibrated at an ambient temperature of 70 F how will it perform at the top and bottom of the specified ambient range?

Is the clock sensitivity to temperature an issue?

How big is the chip temperature rise with the heat sink attached versus no heat sink?

For it not to be an issue the temperature rise has to be pretty large and if that is the case then the device is possibly operating at a much higher temperature with no heat sink. If the temperature rise not large then the clock sync thermal sensitivity is pretty high.
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Gerald - K5SDR, Employee

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Dear Bill,

You have no reason to be concerned about the clock alignment with the new heat sink installed or even the original one.  All FLEX-6000s use this same automated clock alignment system since 2013.  Until now, none of them use an external heat sink - only a larger PCB ground plane.  With the new heat sink, they operate cooler than on the older radios.  The thermal adhesive is specifically rated to at 36 pounds of pressure at 100C!!!!  It will be extremely hard to remove once it is fully set.

By the way, the problem with the old heat sink was thermal adhesive quality from the original manufacturer.  The new heat sink is specifically rated for the application. 

Gerald
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Bill -VA3WTB

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Gerald, is there any benefit to adding heat sinks to the ones in the 6500?
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Douglas Maxwell

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Is this to do with the interface timing between the ADC the FPGA? If so, when the ADC heats up too much, data cannot be recovered correctly by the FPGA? If so, it sounds like this interface works within a small ambient temperature range and that Flex may have added the heatsink to extend the operational temperature range of the interface before clock to data setup and hold timings are affected? Why else would you put a heatsink on a part that doesn’t require one? Freezer spray anyone?
PS. I have a 6300 and a 6500 and both had problems with heatsinks falling off. The danger of one falling off should be enough not to use this methodology again. This lesson was obviously not learnt in the rush to secure more software development funding. When did you last go portable with a 56” plasma screen?
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Gerald - K5SDR, Employee

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Bill,

There is no harm but not a lot of benefit to adding heat sinks to the ADC on the 6500 because it is on an eight layer 10" x 10" PCB with four ground planes.  The 6400 and 6600 use small plug in PCBs with two ground planes so we added the heat sink on those models.  

Gerald
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sky

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Are next month's (June and beyond) build of 6600's going to have the corrected adhesive fix implemented in their construction?
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Gerald - K5SDR, Employee

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Douglas,

Let me try this once more.  The ADCs on the 6300/6500/6600 are on large PCBs with four ground plane layers and vias from the ADCs.  The 6400/6600 use a new modular design on 1 inch x 1.5 inch 4 layer PCBs with two ground planes.  We added the heat sink to make up for the smaller ground plane area on the PCB.  We went to the modular design for both manufacturing and service reasons.  The original heat sinks were defective from the heat sink manufacturer so they fell of.  The replacement heat sinks are rated at 36 pounds at 100C.  Once they set they are very hard to get off.

We have many many thousands of these exact ADCs and FPGAs operating in the field with exactly the same clock synchronization without issue.  With the new heat sinks the thermal profile is in the correct range and the specs for adhesion are appropriate.  

Gerald
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Gerald - K5SDR, Employee

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sky,
As stated several times here on the Community, everything shipped on or after April 12, 2018 have all of the performance upgrades.
Gerald 
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Douglas Maxwell

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Hi Gerald,
If it isn’t to do with interface timings, why does it degrade receiver performance when the heatsink falls off?
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Gerald - K5SDR, Employee

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Steve and I both covered this in earlier posts.  The heat sink helps spurious free dynamic range by a few dB.  Steve provided the datasheet reference in his post.  It does help with timing on the small PCB but not on a large PCBs on the older radios.  This was covered in detail in more than one of my earlier posts on this thread.  Please read back through all the posts Steve and I made in this thread for the detailed responses.  

Bottom line.  With the new heat sinks installed it is a non-issue.  

Gerald
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Douglas Maxwell

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Hi Gerald,
I probably don’t have to understand, but I am a potential customer for the 6600 and at the moment I am concerned with design quality. My understanding so far is that the new small board doesn’t dissipate heat as well as older larger board. As a symptom of this, the interface timing between the ADC and FPGA is affected on the new smaller board over its operational temperature range. The solution is then to add a heatsink to the ADC on new smaller board to better match the old boards PCB stack up thermal profile?
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Gerald - K5SDR, Employee

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Douglas,
Yes, the heat sink on the smaller board replaces the larger PCB from a thermal standpoint.  We measured and compared the different design approaches with a Fluke Thermal Imaging camera.  The measurements show that it meets our thermal and mechanical design criteria.  We could actually change the FPGA code for a wider tolerance range but believe it or not it is less costly to change the heat sinks.  ;>)
Gerald
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bahillen

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I just replace the heat sinks on my Flex-6600 for the SCUs. It took 45 minutes as suggested in the Installation procedure. It was simple and straight forward. 

What I learned in doing this PEN. 
1. Follow the procedure. By this I mean remove the cover while the radio is powered up. This will allow you to get to the removal of the heat sinks while the glue is still warm that may make the removal a little easier.

2. Note that the vents on the lid are toward the front of the radio. it will make the re-installation of the cover easier so you don't put it on backwards. 

3. My heat sinks were still glued but had moved down and rotated a little. I had the radio on for 24/7 since February. I had to pull on the heat sinks pretty hard to get them to come off. I wiggled them a little but may not be a good idea as the old heat sink may cause a problem with L2 and L3 inductor chips right next to the heat sink.
 
4. I would recommend before you start the Installation that you listen to a couple bands to see signal strengths and noise levels so that when you finish you can listen again as a radio check. I also check one Antenna then switch the antenna to the other port to make sure they were working the same. The band was poor when i did the heat sink installation so I was concerned at first when I put the radio back in service.

5. The installation of the heat sinks is straight forward but if you are a not a handy person you may want to have someone help. It would beat shipping back to Flex for a repair. Study the two cautions and know what parts they are talking about to watch not to damage.

6. The glue on the new heat sinks is good. I mean make sure you have it aligned before putting it down on the board, you get one chance to apply. It wont move. It was a surprise that the new heat sink mount on the non component side of the board so I had to read the instructions a number of times. Study the instructions before you start.

73
Bill
W9JJB
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Jim-KB1ZNV

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Completed the PEN according to the procedure on my 6600M. The copper sinks were still in place and harder to pull off than I thought even after the over 30 min warmup. Fortunately the boards were very well made so they didn't bend. I had the torx screws removed while it was still warming up so the heat sinks didn't have too much time to cool down. Pretty easy to do but for a minute I worried that I wouldn't be able to pull the heat sinks straight off but all went well.
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Tim - W4TME, Customer Experience Manager

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In response to Jim-KB1ZNV comment about the existing heat sinks being hard to pull off, some of the adhesive used on the heatsinks worked better than others and the chips are still solidly in place even after the 30 minute heat up period. 

If you are concerned about damaging the board or accidentally scraping pff components on the ADC board and you do not want to send your radio into Service to have it installed,  you are not required to remove the existing heatsinks.  Just apply the new heatsinks to the back of the board and take a very small plastic tie wrap or something else non-metallic like twine and install it around the board to hold the copper heatsink in place to prevent it from ever falling off.  It does not need to be tightened very much to hold it place. 
(Edited)
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matt_bohl

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Where do I find out the serial numbers of affected 6400's or the date of manufacture that this stopped being a problem?
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Steve K9ZW, Elmer

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@matt - read this whole thread. The date is mentioned. 73
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David Decoons wo2x, Elmer

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Radios shipeed on or after April 12th have the update. If you have a new radio then you are fine.

Dave wo2x
(Edited)
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Tim - W4TME, Customer Experience Manager

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April 12, 2018
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Douglas Maxwell

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This will stop being a problem when it’s fixed in firmware.
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Michael Walker, Employee

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Doug, I am not sure I understand, but this is not a firmware issue.

Mike
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Douglas Maxwell

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Have a look at Gerald Youngblood’s last post on this issue. I read this as the correct fix was in firmware but this being too expensive, a heatsink was placed on the ADC to sort an interface timing issue between the ADC and the Virtex 6 FPGA. The rx noise level jumping is all about this interface timing and how ADC samples are captured by the FPGA. Putting a heatsink on the ADC changes the interface timing for the better, but now the interface is more susceptible to temperature changes. Have flex passed this solution through a temperature chamber through its entire specified operational temperature range paying particular attention to rx noise floor levels?
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Tim - W4TME, Customer Experience Manager

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You misinterpreted Gerald's comment. When the ADC runs too hot, two things occur; the dynamic range of the ADC decrease (there is a linear relationship between DR and temperature) and the clocking of the chip changes too.

If the thermal issue with the ADC was not resolved by the upgraded heatsink, changing the FPGA code would not have fixed the dynamic range problem, it would have masked it.  That is why there is a wink emoji after his comment.

The new heatsink provides more thermal mass and more efficient thermal transfer than the previous components.  And yes, we have tested it and it meets our specs.
(Edited)
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Douglas Maxwell

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Thanks for the quick response Tim, I am encouraged to hear that this solution doesn’t compromise the specifications of the radio. The symptom of occasional raised noise floor due to odd operational temperature extremes such as field day, dxpeditions etc. as opposed to normal shack operation would be very hard to spot unless you deliberately set out to check for it with a dummy load and knew in advance what the typical noise floor should be. Thanks for this clarification.
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Tim - W4TME, Customer Experience Manager

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You're welcome, Doug.
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WQ2H - Jim Poulette

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Gerald,
The whole story? Maybe.

While the problem is clearly an annoyance, I really think you're being overly hard on yourself here.
I've been an ME in electro-mechanics for decades, electronics, optics, mechanisms, motion control, the whole ball of wax - and it looks to me like the design side, at the time, had it basically covered. Could it possibly have been the "hand-off" to manufacturing engineering / manufacturing?

I've worked with these "PSA heatsinks" and what killed us was a lack of process control - making sure the mating surfaces were clean, consistent quality of the PSA, keeping the PSA itself clean and uncontaminated prior to installation, and of course environmental controls during assembly (humidity very bad....). The heat characteristics and tensile strength of the bond is pretty cut and dry. The process - maybe not so much.

Glad to hear it's been resolved - personally I love the PSA heatsinks. We use them sucessfully in many instruments, stationary and handheld. Maybe you have to come from the ole' EccoBond thermal epoxy days to really appreciate them.
73 Jim, WQ2H
(Edited)