Hey all,
Recently picked up an MV4 board in unknown condition from a big lot of boards. I've yet to power it on as I'm still waiting for my GBS8200 and GBS Control to get here, but there was a few things I wanted to discuss before doing so.
It has had some previous work, the capacitors on the sound amp side were all redone (quite poorly), the battery has been replaced by another Saft cell (this one has no glue), and 2x of the RAMs have been replaced with CXK58257s (top 2, so I assume L9 and K9?). I also noticed a red marker line across the PRO-B0 chip, which is very worrying unless this was just an "OK" from the factory (can't find any pictures that support that.)
I realize it's really hard to diagnose without powering the machine on, but does any of the work done previously coincide with any common issue (possibly bad YM2610 is what I was thinking)?
And when I am to power it on, how would I know the PRO-B0 is bad, would that be a "Z80 ERROR" due to it being the interface for the Z80? Or would other errors in the system self-check come first? There's not much info on the MV4's PRO-B0 out there other than a pinout and generally "what it does."
Thanks in advance.
Recently picked up an MV4 board in unknown condition from a big lot of boards. I've yet to power it on as I'm still waiting for my GBS8200 and GBS Control to get here, but there was a few things I wanted to discuss before doing so.
It has had some previous work, the capacitors on the sound amp side were all redone (quite poorly), the battery has been replaced by another Saft cell (this one has no glue), and 2x of the RAMs have been replaced with CXK58257s (top 2, so I assume L9 and K9?). I also noticed a red marker line across the PRO-B0 chip, which is very worrying unless this was just an "OK" from the factory (can't find any pictures that support that.)
I realize it's really hard to diagnose without powering the machine on, but does any of the work done previously coincide with any common issue (possibly bad YM2610 is what I was thinking)?
And when I am to power it on, how would I know the PRO-B0 is bad, would that be a "Z80 ERROR" due to it being the interface for the Z80? Or would other errors in the system self-check come first? There's not much info on the MV4's PRO-B0 out there other than a pinout and generally "what it does."
Thanks in advance.
