A while ago I bought a Philips / Fluke PM6306 which was supposed to contain the PM9565 DC-option, but it was unfortunately missing.
As those of you know that have been searching for a PM9565 DC-option unit it is more or less unobtainable these days unless you come by one from another unit.
I Googled some and found this forum and the thread from user "coromonadalix" where he embarked on this journey:
https://www.eevblog.com/forum/testgear/phillips-fluke-pm6304-pm6306-pm9565-dc-measurement-option-board/ since I read that user "HighVoltage" owned a PM9565 DC-option unit I sent him some messages asking for better photos of the circuit board so that I could check to see if it would be possible to make a copy that would be as identical as possible to the original design. I got some very good photos back and embarked on this journey myself and now after some months I've finally been able to build the first circuit board as not only took it time to trace it but I have struggled to get hold of the components now that they are hard to find due to the Covid-19 pandemic.
There were some BOM-errors that I had to fix as well as making a 10K/0.1%/5ppm/0.4W resistor from four 0.2W resistors put in series and parallel. I was also given some of the Mini Melf resistors from an eBay seller that was kind enough to share from his large stock when I explained what I was going to use them for, I missed the auctions where he was selling these values I needed.
I put the circuit board in my PM6306 a few days ago and have made some initial measurements and they are all find. The service manual for the PM6304 says that the instrument needs to be re-calibrated after a PM9565 DC-option unit has been installed and that is the only nut to crack as there is no service manual for the PM6306 to be found anywhere and it differs from the PM6304 instrument. There has been a partial success in finding the commands used for entering calibration here:
https://www.eevblog.com/forum/repair/i-have-found-fluke-pm6306-rcl-calibration-command/ but it seems no one has found the store and exit commands so that is the next nut to crack.
You can see my unit working here:
As soon as I have been able to calibrate the PM6306 with my PM9565 DC-option unit I'll release the files for the circuit board as well as the updated BOM so that anyone can build their own PM9565 DC-option, but without the calibration it is not usable for any proper measurements.
A big thank you for all help from "HighVoltage" & "coromonadalix" as this project would not have been possible without their help!