CPS1 A-Board 89626A-4 with Zilog Z80A 8400W2N A 4 MHz & other components not usual

[chacal231077]

Hi!

I am preparing a Motherboard for a future Multi-CPS1 of a Person.

I have a sound problem, like a snare drum effect, no bass in the game and the sound of the Go! is acute.

I tell myself that perhaps the OKI 6295 Audio Mixer must have taken a beating as usual.

But during my inspection I saw several brands of not too common components.

I realize that the Z80 & a 4 MHZ version, the 6295, has no brand, and that the Crystal has a brand that I have never seen.

what do you think ?

THANKS

 

[ForestOfDreams]

I would suspect the crystal might be a 4 mhz relabeled.
If that doesn't solve it the knock off 6295 is pry it.
I repurposed a china bodged Cps1 and it sounded fine after swapping the crystal and it used a Z80A so that's pry fine too.
It still has a knock off 6295.

 

[chacal231077]

ok I will inspect this

Thank you

 

[chacal231077]

Hi!

Here I changed the Oki, put 2 sockets one for the Z80 and one for the Crystal.

I put the Crystal & the Z80 which are both original basics from another motherboard I own.

The sound is a little better but still treble and lacks bass.

Only the YM2151, YM2151 and 5218A remain, if they have a problem.

Thanks again for your help