Posted By
Haplo
on 2019-10-02
22:17:49
|  Question about 8501 and TED
Hi all,
I have recently got my hands on a Plus/4. I get blank screen when powering it up (using AV cable). It is probably either TED or the 8501 that is gone.
Unfortunately I don't have any spare ones to try out.
To help me figure out which one has gone bad, I have a question: assuming one (and only one) of those two chips is bad, if I leave the machine on for a few minutes, would the other one get warm? Or not necessarily? Or in other words, will the functioning chip warm up regardless of other faults in the hardware? Thanks.
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Posted By
Luca
on 2019-10-03
02:30:53
 | Re: Question about 8501 and TED
Haplo, yes that's a good method in order to spot the malfunctioning one, but based on my experiences the bad IC is the warmer one, and you can unveil it just in a minute or so.
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Posted By
Haplo
on 2019-10-07
21:00:55
| Re: Question about 8501 and TED
Thanks. I have some more information.
Both TED and 7501 get hot. 7501 gets hotter than TED. Also, the TED temperature seems to be stable, but 7501 fluctuates between hot and very hot.
Does this tell you anything about which chip is dead?
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Posted By
Luca
on 2019-10-08
02:19:17
| Re: Question about 8501 and TED
Hey, it is an empirical method in the very end  Hence, voltmeter in hands or trial&error.
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