them and then fix accordingly. I haven't actually plugged the monitor or
the iigs for fear of burning the power supply or monitor circuit boards.
Logan T wrote:
them and then fix accordingly. I haven't actually plugged the monitor or the iigs for fear of burning the power supply or monitor circuit boards.
Unless it was stored for many years in some hostile environment, I think you'll find the Apple IIgs is among the most reliable Apple II models ever produced, especially the ROM3 which you have.
I recently came in contact with a iigs and was curious if anyone had a circuit layout or schematic diagram for recapping. sorry for my ignorance because this is my first repair. the model of psu is astec 6990126. i believe my motherboard is a Rom3.
Logan T <logan0...@gmail.com> wrote:
I recently came in contact with a iigs and was curious if anyone had a circuit layout or schematic diagram for recapping. sorry for my ignorance because this is my first repair. the model of psu is astec 6990126. i believe my motherboard is a Rom3.Are you sure it needs recapping? The most I've needed to do to a IIGS motherboard is replace the dead battery. If it's a ROM 3, it's easily replaced with a 1/2 AA lithium primary battery, such as this:
https://amzn.to/3GQUwB3
If it's a ROM 01, you'll need to cut out the original hardwired battery.
You can then put in a holder to facilitate easier replacement in the future, such as this one that takes the same 1/2 AAs that the ROM 3 uses:
https://www.thingiverse.com/thing:3407875
If it's a dead power supply (you didn't say if it's the motherboard or the power supply), my understanding is that it's the line-filter capacitors (yellowish, rectangular, with foil wrapped up inside) that tend to go bad if anything goes bad. I think there's one that'll keep the supply from firing
up if it goes bad; removing it or replacing it is supposed to get things working again.
As for the electrolytics, these power supplies were built ~20 years before counterfeit electrolytic capacitors were even a thing, so unless you've confirmed that they're leaking or the power supply is not working, I would
be inclined to leave them alone.
--
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?
Logan T wrote:hello
I recently came in contact with a iigs and was curious if anyone had a circuit layout or schematic diagram for recapping. sorry for my ignorance because this is my first repair. the model of psu is astec 6990126. i believe my motherboard is a Rom3.Are you sure it needs recapping? The most I've needed to do to a IIGS motherboard is replace the dead battery. If it's a ROM 3, it's easily replaced with a 1/2 AA lithium primary battery, such as this:
https://amzn.to/3GQUwB3
If it's a ROM 01, you'll need to cut out the original hardwired battery.
You can then put in a holder to facilitate easier replacement in the future, such as this one that takes the same 1/2 AAs that the ROM 3 uses:
https://www.thingiverse.com/thing:3407875
If it's a dead power supply (you didn't say if it's the motherboard or the power supply), my understanding is that it's the line-filter capacitors (yellowish, rectangular, with foil wrapped up inside) that tend to go bad if anything goes bad. I think there's one that'll keep the supply from firing up if it goes bad; removing it or replacing it is supposed to get things working again.
As for the electrolytics, these power supplies were built ~20 years before counterfeit electrolytic capacitors were even a thing, so unless you've confirmed that they're leaking or the power supply is not working, I would be inclined to leave them alone.
--
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?
my rifa according to what u said looks like it might be bad. for what I
am going to use this iigs for, at least to start with is just learning
the basics, so I believe electrical noise probably wouldn't hurt me
unless it actually is bad enuf to damage the iigs motherboard which I
doubt. ok Im acting like I know how psus work but I don't think that that will be a problem. ther is a big black 330uf in the center on my psu, understandably ther are different models of psus used so I'm not sure if
this is what you are referring to in "is a 220mf"but this one doesn't
look leaking. in fact all the caps look all right to my knowledge. I want
to boot up as soon as possible and let u all know my results
Wholesale capacitor replacement without any demonstrated need is a peculiar superstition that is mystifying to electronic technicians.
Michael J. Mahon <mjmahon@aol.com> wrote:
Wholesale capacitor replacement without any demonstrated need is a peculiar >> superstition that is mystifying to electronic technicians.
I have a 70-year-old RCA AM radio that I went through maybe 25 or so years ago and replaced all of the waxed paper capacitors with metalized film capacitors, as those are a known point of failure for devices that use them. I don't recall if it used any mica capacitors, but if it did, I would've replaced them as well because you might as well while you're in there.
There was also a two-part electrolytic capacitor that clearly wasn't working (someone else had hacked in two separate capacitors, one of which had a
loose lead flapping in the breeze), and one or two tubes tested weak.
These changes turned a non-working radio into a radio that still works
today, and whose only likely failure mode at this point is a tube failure.
Shotgun capacitor replacement as a practice may have come from replacing classes of parts known to be troublesome, like paper-dielectric capacitors. It might not always be appropriate for newer equipment, especially if it's known to be in good working order.
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