Commodore 65 electrical scheme

[spirantho]

What do you need the schematics for? Are you still missing chips? (And well done on finding those chips! They must have been very tough to find!)

[spirantho]

I think everyone's still dumbstruck you managed to find those chips (who did you have to hold to ransom to get them, anyway? ).

If all you need are crystals then your best bet is to find a C65 owner (you can find them on any street corner. Or alternatively try the commodore-dedicated websites) and ask him very very nicely to look on his motherboard as it'll be printed on the crystal, and you should be able to get a direct replacement from a donor machine (not a C65!) or from an electronics store.

[spirantho]

No answers?

We're all waiting for YOU to tell US.

You're asking questions about a very rare and little-understood machine...

[spirantho]

Can you list ALL the socketed chips you have on your board please? That is, with the full markings including revision numbers and everything? Maybe we can spot an incompatilibity...

Have you check the address lines on the CPU with an oscilloscope to see if it's running?

[spirantho]

Unfortunately the chances of these boards never being fully populated because they didn't work is rather high - I hope that's not the case here.

I believe U15 is a standard TTL logic chip: a DM74LS125AN in fact - a quad tristate buffer.

It's just possible - but unlikely - that your board would run with the socketed chips Xeno has - what are the revisions on the chips on your board please? Maybe we can get one C65 working...

[spirantho]

Remember you need a revision 3 or 4 Victor chip for a rev. 2B board. A 4510R5 (which is what you have on the first page of the thread) will *not* work in a 2B  - the pin-outs are different - you need a 4510R3 or 4510R4.

I feel a bit bad for having to say that - it's like saying to someone "oh, that hen's tooth is no good, it's an incisor and you need a canine" (for the benefit of people outside the UK, "as rare as hen's teeth" means exceedingly hard to find).

Maybe someone out there has a rev. 3 or later board and a rev 3 or 4 4510? That'd be good for both of you!

[spirantho]

Actually, it will - if your CPU belongs to your board then it must be an pre-R5, which means it would work.
I suspect you may be getting a mail from Xenobiotical quite soon....