Genesis Model 1 systems - No video or audio - Advice?

Hello all,

I've dug up a couple Model 1 Genesis systems (1: IC BDM5 USA / 2: IC BD M5 USA VA2) that both exhibit the same behavior:
They power on properly - 5V out on both voltage regulators, but no video or audio output through either composite or RGB. (I don't use RF, so that's untested.)

I've scrubbed down both systems to eliminate dirt and corrosion as a possible issue.
I know both worked at one time, but they were packed in a box for repair when I have time (which is now ).

I've re-flowed the pins on the cart slot. Nothing else has been touched. The caps all "appear" to be good.
Not looking forward to doing a full recap on these, only to end up right back where I started.
If the answer is to label them as parts units, due to bad video RAM, etc. - That sort of advice is appreciated as well. (Is there a way to test the RAM or other ICs without video?)

There's not a lot of information around as to where I should start on diagnosing these, so I'm hoping someone can let me know where to start on the board.

Thanks in advance!

 

Update for anyone curious - 1: IC BDM5 USA ... I can get SMS games working with the power base converter. Looks like most of the information I was looking for is over at Sega 16.

All ICs reflowed on both systems, with no change in performance. Will be swapping voltage regulators next on system #2 and perhaps on #1 as well. Maybe I'll swap out a few capacitors and see what happens also.

 

Unfortunately these systems are almost 30 years old! The capacitors are well beyond their shelf life. If u are going to refurb these systems, I would recommend recapping them all. U have to remove the cap to test it so u may as well replace it. If I were going to sell on a retro console I would check the IC and cart slots like you have done, but also replace all electrolytic caps.