Full power transmission will crash and restart itself

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  • Updated 2 weeks ago
6600M at 40 meter band,
when ATU bypass, if tune, SWR is 2.8.(My antenna tuner MFJ-998B is not working very well)

Full power transmission ,6600M will crash and auto restart.

when 6600M ATU open,everything is OK.

Is this normal?
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BG6SNJ

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Posted 2 weeks ago

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Michael Walker, Employee

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Official Response
No, it is not normal.  

Items to test:

  • Run the same test, but transmit into a dummy load - this will help eliminate RFI as the problem
  • Measure the power supply voltage at the radio to make sure you are not having a voltage brown out.
Those are the 2 majout items that can cause the radio to crash and reboot.

Mike
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BG6SNJ

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I finished the test
Everything works fine when using  a dummy load.

but swr 2.6 or 2.8 when tune, the 6600M will crash?
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Paul Menown

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Take the mfj out of circuit if you are using internal atu
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BG6SNJ

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My antenna is an 84-meter skyloop ,and 4:1 balun to the MFJ-998RT.
Because I use the amplifier, the 6600M internal atu can't work.
When I only use 100W, it may be possible, but the Feeder sheath may have radiation.

sorry, my english too bad. haha.

73 de bg6snj
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Burt Fisher

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I have something similar except I have the problem even on a dummy load
https://youtu.be/W1SP7PD6GQc
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Michael Walker, Employee

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Burt, what make and model of power supply are you using and how old is it?  
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Burt Fisher

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Astron 20A but resets below 20A, age unknown but the meter is constant and it doesn't reset if the ATU is engaged.
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Michael Walker, Employee

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My Astron 20A fails every time on the low bands and both a 6600 and a 6600M.  It isn't RFI as I can run 2000 watts out the back of the amp without issue.   The SS-25 does not.  That is from personal experience. 

With the ATU, you may not be using the same amount of current.  Just to be sure, I would add an amp meter in series on power cable and see how it goes.  

I'm pretty confident this isn't a radio issue, but a power supply issue.
(Edited)
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Burt Fisher

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The power supply already has an ammeter, it doesn't get near 20 A  at 80 watts. But it crashes
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Michael Walker, Employee

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When it crashes, what happens to the voltage when measured on the back of the radio?  I bet is sags down around 11V.  Are you sure you can trust the Amp meter readings?   Also, analogue meters are pretty sluggish.   I would swap out that power supply and test again.  

I would also clean the contacts at the fuses.  It only takes about 0.2 of an ohm resistance at 18 amps to drop 3 volts.   

Areas you need to check:

  • Power supply sag
  • Less than 0.5 ohm resistance in the power delivery/power cord 
  • Clean the area the fuses 
  • Try another power supply - as a test, raise the idle voltage of the power supply to 14.5 volts instead of 13.8V
However, since my 25 year old Astron 20A is doing the same thing on 2 different radios, I am highly suspecting the power supply and once I get up to my remote station, I am going to swap it out for another power supply.

It does not do the same thing on the SS25 or the Alinco DM-330MVT supply in my case.   Feel free to feed back after you have done the above tests.

73
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Mike - VE3CKO, Elmer

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Good point Mike, I have 3 Alinco DM-330 and one is dedicated to just the Flexradio. Even so I experience crashes/lockup in the past on 80m when using an amp. I have beverage antennas on both RXA and RXB so I moved the amp a few feet more away from the 6700 and loaded up on ferrites on everything connected to the radio including looping the power cord through a larger ferrite. That took care of it.
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Michael Walker, Employee

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Burt, sounds like your RS20A is working as designed.  It is browning out just past 16 amps and that is all it can do continuously.  It is a 20A peak meaning, ok enough for SSB only and not for any constant carrier modes like CW, RTTY or FT8.
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Michael Walker, Employee

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Official Response
Tim and I discussed this this morning. 

The RS-20A power supplies just don't have enough and I went and dug up the specs.  The RS20A is a 16A continuous supply and 20A ICS.  We need closer to 25.  

This is why the SS-25 is a 20Amp continuous and 25A ICS (Intermittent Communication Service - aka - peak).

If you have to run an RS20A or similar, go into the the radio and set your maximum TX  power to about 80 watts until you have a chance to upgrade your power supple.  This is in the TX menu.

Mike