I measured V at the p/s and at the cord end at the radio. I have a 20A circuit breaker in the amp power line, and checked across the post and ground there, on the aux side of the breaker. That is also where I checked current..
I was told it was tuned up at Bob's in Pa, not sure where that is. Had a sticker on the side "void if removed" with the name on it, but that was gone the first day as I took it open to see if AMC was clipped out or whatever else I could see done.
I went back to another radio I've worked in several methods and I'm trying to find a board that more closely matches.
There is the problem with a upward spiral of technology getting in the way...the 939 is missing several key areas, you'll have to extrapolate from ones at the site they have information for.
There is the issue of Bipolar, versus MOSFET - you'll see that on the back panel - and it changes the parts count considerably. One earlier generation used Bipolar an all it's support parts then the MOSFET came along and now has added some complexity because even the silkscreen may not show proper diode orientation - they used up and earlier generational board to make the newer upgraded model - so it tells you they are electrically similar - just may not be printed right - which may be the entire problem we're having to deal with here, in the first place.
Perhaps this link may help you locate more of those parts - it's for an older predecessor board but it is for the same layout - its for the 949 - so DON'T PANIC - it is for you to help you...the 939 has a different switch (front panel) layout but the board are nearly the same - identical to the parts used, but some of the layout may not have what your board has.
http://www.cbtricks.com/radios/galaxy/index.htm
The above link is for the purpose of seeing all the site has to offer - not just one but all board types they've got - see if it helps you - I'd personally go to the 949 link - and yes, the Bipolar and MOSFET ones are there - but pay attention to your board number silkscreened on the board for the foil traces and numbering too...all are affected.
On top of that they also have a 959 that has a similar switch and front panel layout as the 939 but it's for SSB and AM modes on top of that all labeled differently - but uses a similar board - go figure?
These are the banes of upstaging to the next platform - THEY use the SAME BOARD, PARTS but the display and switch front panel layouts are different.
But electrically they perform - similar so refer to the 959 for front panel layout but 939 for schematic, 949 can also help for the main PCB layouts, but refer back to the 939 schematic for proper values - ok?
It wouldn't hurt if you opened multiple tabs on your browser and toggled from one to the other to help you find what you need.
(I had to go back and update this so this the best I can offer at the moment)