You could just bypass the Scott board.
For the 205:
20 way connector
Harwin M80-8662022, 20 pin, 2 row thru hole, 0.1" x 0.05"
Pins 1-3 are +ve, pins 4-6 are -ve battery supply.
Pins 7-9 are 'external +ve' and 10-13 'external -ve
There are a couple of 'switch' signals on there too, but I cannot find out what they did. Suspect they switched on or off allowing external power to stay live.
The image below is a 205 installed on an Argus 3 chassis, showing power is only connected to pins 1/2 & 5/6. I doubt there was anything else on that tiny PCB, but if you get trouble I can go and look harder. I seem not to have the design file either.
The spec says OK between 4V - 9V, and as usual at this era it takes somewhere around 8W until the peltier settles, then about 5W.
Argus3 was 5 x NiMH cells.
The 80 way is all signals, and annoyingly the analogue video only comes out on that one.
I noted that if not terminated, you will not get a video signal.
regards
Bill