Sega CD2 not reading 100% issue

[omp]

Hey guys please bare with the longish post

A while ago I bought a lot of Sega CD's (1 Sega CD and 3 Sega CD2's). Out of the Sega CD2's, 2 had Samsung lasers, the other has a JVC Optima 6S. With a bit of mucking around (and new lasers) I got all 3 Sega CD2's working....or so I thought. The Sega CD2's with the Samsung lasers work beautifully. The one with the JVC laser, not so much.

When I originally tried this Sega CD2 the disc wouldn't spin at all. I had a parts Saturn that had a good laser so I fitted it into this Sega CD2 and it appeared fine! So I bought another laser just for this guy, it arrived and I fitted it and it worked ok (tried only 1 game US version of Stellar Fire). Today I installed a multibios using the 3 std BIOS's so had the opportunity to try more games.

I tried
PAL Mickey Mania would load to intro screen then black screen, disc spins and nothing else.

JPN Final Fight ages to load and when it does no background music just sound effects

US Ecco Long to load and no background music....sort of, the music would start then stop....

JPN Arcade classics (Golden Axe) Long to load no background music only sound effects. Occasionally the music would start, skip a beat or two and then repeat itself then go away alltogether

PAL Soulstar appeared to work ok-ish

When I initially got this console, it had been taken apart (no first time screw "crack" on removal) and the 4 trim pots on the CD drive board were all sitting at the halfway point which I thought was a bit odd. So I am of the opinion these trim pots have been fiddled with.

Does anyone have any advise (apart from willy-nilly turning these trim pots)?

I was really happy getting all 3 Sega CD2's going, so this has been a bit of a mild let down.....

The Sega CD is toast as someone has a had a ball on that one lol!

[APE]

And you didn't try reverting back to the stock maskrom to see if the BIOS may have been at fault?

[omp]

Hmm I will give that a go. I got 4 multi-bios chips and I tried this one in another Sega CD2 (although it is an earlier revision model2 with Samsung laser) and it worked fine.

[l_oliveira]

People should stop using those ridiculously old multibios chips and use the region free bios instead.

Don't be an butcher and drill holes on the poor thing. :-(
Region free BIOS is one BIOS that boot all discs.

Also, to make it read the discs better:


:nod:

[omp]

Thank you for the replies

I took it back to standard with the eprom socket removed and the standard BIOS back in it's place.

No change unfortunately, I spoke with TmEE (over at sega16) about it, he was saying if the trim pots have been assed around with, it would be hell trying to "wing it" back to being correct as you need a scope and other proper tools. I believe it has been fooled around with as it would be very unusual for all 4 trim pots to be in the central position. There is an electronics repair shop not to far from home that may be able to set it up for me.



I considered the region free BIOS, but I can't read Japanese (for sorting out formatting the memory etc). I also don't have an eprom burner, so I had them done elsewhere.