OPL4 family

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By Ciro

Supporter (11)

Ciro's picture

10-03-2013, 14:30

Hello!, this are the correct values:

They are in a mirror format c4,c5,c12 - c2,c3,c11: c4=c11, c5=c3, c12=c2.

The correct value is 0.039 uf instead of 0.033 uf, but there is no ceramic capacitor with this capacitance but polyester (too big), so I used the close value.

C22 is used to filter +12v op-amps. Is missing in some photos because a had trouble with them, so i decided not to use them. I think I got a bad batch, the problem is that they get shorted causing +12 drop to 0v (not good for the MSX), the board is fully operational but moult, because the op-amps are not working.

There are picture of missing c4 and c11 because those values are hard to find this days where I live. Later I completed the board when I get them. This capacitors are used in the filter stage of audio, so it is not critical if one is missing.

:)

By JamesBurton

Expert (81)

JamesBurton's picture

10-03-2013, 15:12

Thank you very much Ciro for answering my questions.

I've read the whole story in retrocomputacion and I could feel almost the same excitement you felt with each test, with each advance until you finally got a working cart.

Congratulations and thank you very much for sharing :)

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