I bought 2 new ls374 from a trusted seller, but there's no sound at all. Previously, there was a looping sound almost every time I turned it on, but now it only happens once out of 15 times. What else should I change, 68000?
Repair Log: CPS1 No Sound
- Thread starter ShootTheCore
- Start date
ForestOfDreams
Grand Master
My experience with the chinese cps1 is if it seems like a knock off part it is.
The only way I fixed mine was a full proper recap with correct audio amp and swapping the knock off parts.
Plus reburning the eproms.
I know they seem like a deal but by the time I corrected all that it wasn't.
The only way I fixed mine was a full proper recap with correct audio amp and swapping the knock off parts.
Plus reburning the eproms.
I know they seem like a deal but by the time I corrected all that it wasn't.
duffcon
Professional
Samsies, I got mine working by replacing the SRAM, but I didn’t trust any of the cheap parts, so I just transplanted everything else from a donor with a failed A custom.
DelsArcade
Enthusiast
That's what I plan to do. I also have a bootleg audio hack that works and a donor A PCB with a bad custom. I'm going to move everything over in the audio section and remove the janky audio. I plan to make a vid of this (when I get to it, I have a ton of vids and repairs in queue).
Del
Seems to have solved the problem -68000 transmits to the z80 what to play and at what volume on 2 eight-bit buses. From PAL IOA1, the signals go to the 5B LS32 and then to the 10J, 11J LS374. Using an oscilloscope, I checked that both signals were coming to the LS32, but only the second signal was outputting, and the first output was silent. I transferred the LS32 from the working board, and everything started working. I don't know how long it will last, but judging by the marking, the faulty LS32 was not original. I'll test it to see if the board kills them over time.
channelmaniac
Professional
You can better judge by the soldering on the part to see if it was installed by the factory or replaced at some point in time.