cbm710 questions

From: Nicolas Welte (welte_at_chemie.uni-konstanz.de)
Date: 1999-08-31 22:32:18


I got a CBM710 board (nonworking) recently, mainly to "borrow" a 6525
for my Magic Voice cartridge (MV works now :-). I think it is a 710
board, it has 128k RAM and an external keyboard connector. I'd like to
get this board working again, but I have some questions that I couldn't
answer with the documents on funet, as they only seem to cover the 600
series. Component locations are very different on the 700 series as it
seems. So can somebody please confirm the locations and identity of the
socketed chips, as I have no idea what the previous owner did.

u11 6526a     (This one was inserted the wrong way around, but I fixed
it early enough. Chip works in a C64)
u12 901243-02
u13 901242-02
u17 901244-03
u26 6509R7
u42 TI SN74166
u75 906114-05 (yes, not -04 as mentioned in the 600 service manual)

I'd also like to know if the 50/60Hz signal provided on the power supply
connector is needed for operation. I think it is only used for the CIA
TOD clock, but who knows.

Symptoms are a black screen, I get sync pulses on only one line, the
other one and video are just doing nothing. The PLA gets quite warm,
warmer than the SID. But from what I know from the C64 both temperatures
are quite normal. 


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