On Wed, 2 Aug 2000, Nicolas Welte wrote: > > [COPLIN, Nicholas.] I would have to agree that the 7501/8501 would have to > > be to most failure prone semi-conductor ever made. 2/3 of my Plus4 machines > > are toast and the remaining one works for all of 5mins before it > > "overheats", whilst the 3/3 of my C16's seem to work! > > > > Is the problem model specific? Does anyone know of any fixes to help prolong > > their life (Heat sinks? cooling fan?) > > A heat sink is always a good idea, but I don't think overheating is the > main problem for that CPU. I think it is the same reason why the CIA died > so often in the old C64: the serial bus. On newer C64 and all C128 it is > protected by diodes, and I rarely see a CIA die on them. The service > manuals on funet describe how to add those diodes (at least four, sometimes > six) to the old C64, C16 and Plus/4, and I also did it to my C116. I only have 2 Plus/4's but they have similar problems. They both have the diodes. I suspect the voltage regulators or timing cricuitry, but I have not had the time to test them thoroughly. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
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