32 replies to this topic

[thegamezmaster]

Am using a genesis 1 power supply, just checked the board and can't even find C50. It says M4 on it 1986. The only markings as to which board it is.

[FABombjoy]

Those schematics aren't exactly from the SMS as the power section is different from the production hardware. The logic sections almost there but again aren't 100%.

What is listed as C50 on the schematic is actually:

C4 on 837-6067 PCBs
or
C1 on 837-6629 PCBs

It will be a 100uf cap, not a 220uf as shown.

[thegamezmaster]

Thanks for the update. I'll check it out. I did examine all electrolitic(?) caps and saw no physical damage to any caps and didn't have 5 volts out of reg ic

[Atariman]

It sounds like you should be safe just replacing the voltage regulator. You can get these fairly cheap at Radio Shack.

[FABombjoy]

I can't edit my post above, but as an update, at least one of those caps that I gave is wrong. On the 837-6067 board, C53 on the schematic corresponds with C4. There is no equivalent to the schematic's C50. The board actually has no significant input cap for the regulator other than the ceramics. I haven't had a chance to confirm if this same oversight is present on 837-6629 boards as well, but I suspect that it is. This may contribute to the reduced lifespan of SMS voltage regulators.

[FABombjoy]

Now I really wish I could edit. Even as I typed the above it didn't seem right, so I quintiple-checked my -6067 board and C1 is the same as the weird schematics C50.

The kicker is that it's 10uf @ 16v. Not a very large cap on the regulator input.

[thegamezmaster]

FABombjoy, on Mon Feb 6, 2012 7:26 PM, said:

Now I really wish I could edit. Even as I typed the above it didn't seem right, so I quintiple-checked my -6067 board and C1 is the same as the weird schematics C50.

The kicker is that it's 10uf @ 16v. Not a very large cap on the regulator input.

Thanks for the help!

[thegamezmaster]

Just to update, replaced the voltage regulator and now the deck works perfect! A BIG thanks for all the help. It's just really nice to have the very first video game system I bought post crash working again, thanks again! People who help here are the best!