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*fixed* Chinese hack Forgotten Worlds conversion audio broken

duffcon said:
If you check the link above it tells you what are acceptable SRAM chips ( 2k x 8 - a 6116 SRAM IC can be used to replace it)

My layman theory is that I should replace all the caps, including the missing ones as bad power delivery could have been the cause of the other chip failing. Given I have a donor board, I already have everything I need, so I think I’m going to go for it.
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Found some old stock TMM2015AP-15 Toshiba's and ordered a few.

My concern about the missing capacitors is that the funky diode on the KA51 is reverse polarity (at least it is on mine) so I don't trust that the rest of the capacitor spots are correct anymore.
 
duffcon said:
Yeah, I replaced that with the original parts
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Hum... doubt I have the willpower to do that. I have two bad boards, one is totally stock but has no video and the other is the Chinese modified audio one with no sound. Was thinking I might try moving the CPS-A01 ASIC from the bad audio one to the bad video one to see if that's the issue. But will try swapping out the TMM2015 first first.
 
No sound at all is a bit different than mine was, I just had crazy sounds on SF2 and digital only on FW. Yours may be amp related.
 
duffcon said:
No sound at all is a bit different than mine was, I just had crazy sounds on SF2 and digital only on FW. Yours may be amp related.
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Interestingly the amp on mine is original... still has the heat sink and everything. But yeah, will dust it off and break out the oscilloscope to see what I can figure out.
 
You can’t really be too sure; I have another a board that looks legit (amp) except all the caps are different, a couple are missing (not as many as this one) the z80 is a gold star and a couple of other things. Not 100% stock, different dips also. I could have been a repaired board, who knows?
 
duffcon said:
You can’t really be too sure; I have another a board that looks legit (amp) except all the caps are different, a couple are missing (not as many as this one) the z80 is a gold star and a couple of other things. Not 100% stock, different dips also. I could have been a repaired board, who knows?
Click to expand...

I'm referring to the amplifier IC, where the one you pictured has a TA7252AP mine is still stock with the original heat sink (cant recall the original component part off hand). The capacitors are suspect of course. Didn't have an oscilloscope last time I looked at it, but should be able to test the audio signal going into the amp.
 
Just as a final update; I went ahead and moved all the other components from the donor, caps, surface mount stuff (caps, resistors) and the amp. Everything is working well. Hopefully it lasts!

81150B47-6D57-4592-B988-7D85B29CCAA9.jpeg2D473FE1-E29E-4628-B707-11C8EBDCDCE7.jpeg
 
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