Electronics > Repair
Macintosh SE PSU IC identification
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gkmaia:
That is probably for someone that is familiar with these old macs as there are no PSU schematics for the SE.

I got an IC that is faulty. I know that because I have two of these PSUs and by swapping the IC it works.
Could it be a high voltage optocoupler or a 177 opamp? Identification markings are 177  u8918. I could not find anything online so far... possibly remarked by manufacturer?

I wish I could tell more but that is all I know so probably someone that if familiar with this PSU and have had similar problem?! Maybe?
bob91343:
8918 is the date code, 18th week of 1989, maybe May.

Since it's an 8 pin DIP I vote for an op amp or even a dual opamp.  Most optocouplers would have only 4 pins.
George Edmonds:
Hi

Try the attached schematic
Haenk:
Can't make out any part numbers >300, so it's not the same schematics.

#deleted#
Looks like an Unitrode OEM part...
JKKDev:
Wouldn't it be rather straight forward to test the working IC? Does it act as a diode on one side and a transistor on the other? If you drive the diode, does the transistor turn on? Then you have an opto.
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