WARPZONE
New member
- Joined
- Jan 12, 2025
- Messages
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Hello everyone. I've recently repaired a Taito Chase HQ "z board" that played with no sound at all, and I want to share with you my experience.
The game use to run completely silent (that is a very shame for such a title...), but adjusting the volume pot on the PCB produced noise from the speakers , so the amplifier section was presumably working. Probing the Yamaha YM2610 (IC69) Mighty sound chip with the oscilloscope, I've found that the various sound's digital signals where all present , and all these signals arrived to the inputs pin of the SMD packed YM3016 (IC66) digital to analog converter (this board has got a sound circuit very similar to the Neo geo system), but probing the outputs of the d/a IC shows nothing... So I purchased a new one from China (that seems to be the only place that still sell this kind of IC on Planet earth).
After replacing this tiny SMD converter in IC66 the sound works again
, but many percussive sample and many parts of the speaking voices was pretty bad, distorted and with crazy volumes...
So I've removed the sound masked ROMs (IC70,IC71,IC72,IC73), and checked all of them with my beloved Chinese TL866, comparing them with the MAME roms and two of them tested defective...
In order to read this 23C4001E masked ROMs with my TL866 , I've read them as 27c040 (with IC Id and pin recognition disabled).
After finding on old scrap boards a couple of 27C4001 EPROMs (that is the same stuff as the 27C040) and after uv erasing and writing the right code in them, the problem was finally solved

.
Hope these information may help someone else.
The game use to run completely silent (that is a very shame for such a title...), but adjusting the volume pot on the PCB produced noise from the speakers , so the amplifier section was presumably working. Probing the Yamaha YM2610 (IC69) Mighty sound chip with the oscilloscope, I've found that the various sound's digital signals where all present , and all these signals arrived to the inputs pin of the SMD packed YM3016 (IC66) digital to analog converter (this board has got a sound circuit very similar to the Neo geo system), but probing the outputs of the d/a IC shows nothing... So I purchased a new one from China (that seems to be the only place that still sell this kind of IC on Planet earth).
After replacing this tiny SMD converter in IC66 the sound works again
So I've removed the sound masked ROMs (IC70,IC71,IC72,IC73), and checked all of them with my beloved Chinese TL866, comparing them with the MAME roms and two of them tested defective...
In order to read this 23C4001E masked ROMs with my TL866 , I've read them as 27c040 (with IC Id and pin recognition disabled).
After finding on old scrap boards a couple of 27C4001 EPROMs (that is the same stuff as the 27C040) and after uv erasing and writing the right code in them, the problem was finally solved
Hope these information may help someone else.