Manual needed for C= C64G system (250469 short board version

[WelshWizard]

I now have 3 C=64 left to repair, one Breadbin and two C=64G short board ones the short boards have PCB ASSY 250469 PCB rev 3 mother boards, I have looked every where but have not found a manual for servicing them, as the board changed a lot I cannot just use the older service manual as even the CPU has changed`from a 6510 to a 8500R3 CPU
almost certain the SID chip is the 8580R5MOS chip and the VIC is the 8565R2 chip
but I am having trouble with basic / kernal and char ROMS, So if any one either knows of a manual for these models for sale or even where I could download one it would be very much appreciated

[recycled]

is the circuit diagram any use to you?

http://www.commodore.ca/manuals/default.htm

Bottom left has the CPU you describe.

[Carcenomy]

C64G uses lower core voltages than earlier C64 board revisions. Interesting, both my 64Cs have been C64B3 boards, not the C64G shortboard. Yours must be later production models. Normal service procedure remains to the best of my knowledge, but you do need the correct chips for the job.

[WelshWizard]

a liitle bit at least I now know that the Basic and kernal rom have been combined so that rules out the chips from the States as the one at least gives a screen but show U1 and U4 as faulty, but as this board is so different to the early one not sure how good the test cartridge is on this latter board. I might just try desoldering the chips on the one that does not show any signs of life other than the red light coming on and try subing them one at a time with the partly working board.
This one has a Key board error when you type a letter you get letter next key type always gives and arrow pointing forward type the next key and you get a letter and so on. I know the SID is working as it plays music with a cart game in.
What I really need is the board layout with the Unumbers for the Chips and the correct numbers that should be in the IC sockets or soldered to the M/B
Looking at the Schematic I may be able to work that out.
just in case it works this is the offending animal


If I am correct the chips should tye up as follows, Let me know if I am wrong
U1 6526a
U2 6526b ( can be 6526 the a or b is only to doe with speed which is controlled else where on the C64)
U3 HD74LS08P (14pin)
U4 2312C Char and Basic rom Combined (251913-01)
U6 8500 CPU (MOS8500R3 0687-23)used instead of old type CPU
U7 8565 VIC (MOS8565R2 0687-22)
U8 251715-01 (MMU MOS 254715-01 )
U9 SID D400-D7FF ( MOS 8580R5 - 0687-25)
U10 41464-15 Ram
U11 41464-15 Ram
U12 ?
U13 ?
U14 ?
U15 ?
U16 ?
U17 ?
U18 4066 (14066b)(or MC14066B (ffn 14Pin)
U19 2114(d800-D8FF ) or sanyo lc351aa-15 memory
U20 8701 MOS F6-8701 (16pin)
U21 40066 MC14066BCP (14pin)

what I have not found is the U number for the MC2114-2 chip thats between U8 and U7

[WelshWizard]

Any help or correction with IC to U numbers appreciated

[Carcenomy]

The C64G makes almost all of the random U-number chips (the discrete logic ones down by the memory on the older models) totally redundant - they're rolled into the SuperPLA. I'll go dig in my 64 diagnostics stash and see if there's any 64G specific data for you though sir.

[WelshWizard]

The C64G makes almost all of the random U-number chips (the discrete logic ones down by the memory on the older models) totally redundant - they're rolled into the SuperPLA. I'll go dig in my 64 diagnostics stash and see if there's any 64G specific data for you though sir.

That would be great, SIR,
as I don't think my C64 diagnostic cartridge gives the right answers on the C64G