PEN Heat sink replacement

  • 1
  • Praise
  • Updated 1 year ago
What a classy company. My kit arrived on Friday and it took longer to remove the 14 Torx screws than the update took. I followed the instructions to the letter (at least I thought I did) and after I installed the 14 Torx screws I was ready to put the installation manual in my FLEX hardware notebook. It was then I noted the vertical direction of the fins on the new heat sink in the manual. FLEX did supply a Torx driver (nice touch) but I decided to go and get a set of Torx drivers at Home Depot. They had two one at just under $6 and one just under $10. I opted to spend 10 bucks since it came with a variety of drivers and bits in a nice plastic case. The swivel head made it easy peasy. PLEASE be careful to be sure the heat sink fins are oriented vertical, I am not sure what the issue would be if they were not. Fortunately when I re-opened the cabinet to check that I had not screwed up the fins were the way they should be, lucky me, good to check. Perhaps Tim or Neal can advise if they were not. Anyway done...Thanks FLEX
Neil   N4FN
Photo of Neil   N4FN

Neil N4FN

  • 80 Posts
  • 19 Reply Likes

Posted 1 year ago

  • 1
Photo of Gary L. Robinson

Gary L. Robinson

  • 254 Posts
  • 56 Reply Likes
I got my kit on Saturday and , as you said, it took longer to take the screws out than to do the heat sink fix. All went well and the radio is back on the air and running well. 

Thanks Flex!

---Gary WB8ROL
Photo of Ron W4RDM


  • 43 Posts
  • 10 Reply Likes
Installed my heat sink kit tonight on my 6400. The original heat sink had dropped to the bottom of the board.

The radio had been on 24/7 until the PEN announcement since I received it on Feb 7.  

I moved the original heat sink back to the chip and installed the new heat sink on the rear of
the board. Added the orange wire tie 

Torx screws were not a problem with my battery powered torx driver. Removed and installed the screws in less than a minute. Radio is back on the air.

Photo of mikeatthebeach .

mikeatthebeach .

  • 480 Posts
  • 82 Reply Likes
Anyone know What size are the size of the Torx Screws T# ?? are for the Flex6600
73 Mike
Photo of Rick  WN2C

Rick WN2C

  • 306 Posts
  • 47 Reply Likes
Well Mike, if you have ordered the kit it will come with the proper torx wrench to do the install.
Photo of David Decoons wo2x

David Decoons wo2x, Elmer

  • 1465 Posts
  • 310 Reply Likes

I used the T8 bit and my magnetic screwdriver kit. It was easier than using the T8 L wrench they send. The L will work though.

Dave wo2x
Photo of Wayne


  • 614 Posts
  • 89 Reply Likes
The heatsink fins are vertical so the airflow coming threw from the fan will be unimpede and flow across the fins of the heatsink since hot air rises.
Photo of Neil   N4FN

Neil N4FN

  • 80 Posts
  • 19 Reply Likes
Did you leave both heat sinks installed and not remove the original one?
Photo of Ron W4RDM


  • 43 Posts
  • 10 Reply Likes
 I have both heatsinks installed now. The original had came off and was stuck to the bottom of the board at the connector.

Photo of Neil   N4FN

Neil N4FN

  • 80 Posts
  • 19 Reply Likes
Why have both??
Photo of Alan W4FBI

Alan W4FBI

  • 269 Posts
  • 31 Reply Likes
 I couldn't get my old heatsink off - so I installed the new one, and zip tied - just like the picture.
Also, I wondered why FRS included a couple of case screws - well I found out why. The first screw I took out was dropped and went into deep space. Thank you FRS for thinking of that!
Photo of Mark WS7M

Mark WS7M

  • 505 Posts
  • 153 Reply Likes

I did the same thing.  Both of my old heat sinks were on rock solid so I just left them on, installed the new ones then zip tyed around both.
Photo of Steve K9ZW

Steve K9ZW, Elmer

  • 1571 Posts
  • 772 Reply Likes
Under ten minutes to do the heat sinks on a 6600M. Included the time from disconnecting everything to reconnecting it back up.

A couple quick confirming QSOs and all is well!


Photo of Don N

Don N

  • 9 Posts
  • 1 Reply Like
It was nice to see the noise floor drop a couple db on my 432 xvtr after the installation. My heat sinks had fallen off at some point, and the new ones seemed to make the difference. Thanks Flex for addressing this... better noise perf is great, no more metal objects floating in the cabinet, priceless, hi.

73, Don
Photo of Rich McCabe

Rich McCabe

  • 1122 Posts
  • 240 Reply Likes
Was an easy install for me too.  One of two heatsinks were laying on the bottom.