Hello! Steve Gray wrote: > My P500 is not happy. I've tested all the socketed main chips and they > are ok. The voltages look ok. There seems to be activity in the system > but I'm not sure where it's going bad. I suspect the 6525 might be bad > but it's soldered in, and since my eyes are going bad I haven't been too > keen on soldering these days. A also need to convert it from PAL to > NTSC, which again will need some soldering. My P500 had recently gone bad too, and it exhibits similar behaviour to yours, including similar activity on address lines. I don't believe a broken 6525 would bring a system down like that - the system is still alive, but the CPU appears to have been lost in the address space. A broken I/O chip will not make it - for example, when CIA breaks down in CBM-II it simply brings the whole bus down and the CPU halts. After looking what might go wrong in the system, my bet is on the PLA chip. I will be working on it in some spare time... Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2012-10-02 08:00:06
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