Re: iMac A1224 PSU, 614-0421 - no standby voltages
Holy crap!
The only through-hole components which still haven't been tested are these white ceramics, so that'll be done today.
I understand the differences between resistance, impedance, reactance and the effects of back emf's caused by collapsing magetic fields through coils and hence the need for diode protection, but no doubt I could brush up in this area.
As for the opto-isolators, again, I understand exactly how they work, however I am not yet on top of how, or from where, the feedback signal which passes through them, comes from...
Anyway, unless these ceramics are open, then it will time to dive into the smd section on the printed side.
If so, I'll list all the different chip, FET and transistor types and we'll see if we can't find something open.
I am assuming something has opened, as the fuse hasn't blown, eh?
Originally posted by reformatt
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The only through-hole components which still haven't been tested are these white ceramics, so that'll be done today.
I understand the differences between resistance, impedance, reactance and the effects of back emf's caused by collapsing magetic fields through coils and hence the need for diode protection, but no doubt I could brush up in this area.
As for the opto-isolators, again, I understand exactly how they work, however I am not yet on top of how, or from where, the feedback signal which passes through them, comes from...
Anyway, unless these ceramics are open, then it will time to dive into the smd section on the printed side.
If so, I'll list all the different chip, FET and transistor types and we'll see if we can't find something open.
I am assuming something has opened, as the fuse hasn't blown, eh?
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