Arcade Collecting > Restorations & repair
Defender Restoration
SirPeale:
What little progress I've done, I've logged in brief here:
http://www.pealefamily.net/tech/newmame/index.php?cat=13
SirPeale:
Replaced the 4116 RAM with 4164 and made an adapter. Up and running again!
SirPeale:
I'd forgotten that I bought a couple sound boards off eBay. Went to test them today.
One a Joust (I think) and one another Defender.
Since the ROM was already in the Defender one, figured I'd just plug that one in. Something weird...an extra pin on the power input. I *think* it was pin 7 (which according to a Robotron drawing set, is unused) but I left it behind at the storage area (in hindsight, a dumb move). On the original board that pin is missing. Not knowing if it was a bad thing to chop it off, I left it alone. The board numbers are the same.
Next, the one with the (I think) Joust ROM. It wired up okay. Fired up the game, immediately starts making noise. Continues into the attract sequence. Finally stops.
I play a game. Weird having Defender making Joust sounds. But they're amazingly appropriate.
Next I pull the ROM from my original board and install it...nothing. Not even in test. Okay...
Pull the other Defender ROM and install it...also nothing! Replace the Joust ROM...sounds again. Okay. I think I know what's going on. I see zero ohm resistors on the sound board. From my reading about the ROM board you have to change the "strapping" to get it to see the correct type of ROM. It can take either 2732 or 2532, you just have to change the position of the resistors (essentially jumpers). I'm betting it is similar, but haven't looked it up yet.
SirPeale:
Pulled that "extra" pin out of that one SB. Works great. Still have no clue why it was there.
One theory is that someone replaced the connector at some point in the past, but didn't remove that pin. But the solder looks factory. Whatever. Sound works 100% now.
cw:
:applaud:
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