I am an engineer working for Mr. Takeda at Nintendo. Generally speaking,
the manufacturing companies are not able to support technically and do the
maintenance of too old products out of warranty, because there would be no
spare components to replace or fix, even if we locate the problems. Anyway
Mr. Takeda assigned me to help you, as much as possible, fix the problem of
your Super Punch-Out hardware. However please keep it in your mind that I
do my best to locate the problem, but you should not expect excessively,
because I would not like to make you be disappointed finally.
For your information, I found the pdf file of the Punch-Out's circuit
schematic at
http://arcadeconnection.serverbox.org/arcade machines/english/Punch-Out!! [Operation]%20(EN).pdf.
I attached the file here for you.
So I have a question about your CPU Printed Circuit Board, at the location
of 4F and 4H, Do you find a pair of the same sound processors of 2A03s?
These 2A03s are the processors with sound frequency-modulation features,
which are the derivative version of Nintendo Entertainment System's chip.
One 2A03 generates two channels of sounds, so totally four channels of the
sound sources are to be mixed through tie-up by ohmic-resistors. Anyway
could you check two processors of 2A03 (4F and 4H) ? Thank you.