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IIgs power supply

tblake05

Experienced Member
Joined
Aug 21, 2017
Messages
295
Location
Minnesota
Computer runs. Though I haven’t tested it farther than

“Check startup device!”

Before turning it on for the first time in I assume years, I tested voltages from the psu.

-4.96, -12.02, 10.96, 5.02

10.96 seems a little low, should it be recapped? Are there rifa caps in these psu’s?

I decided to try it anyway, and it does run the machine.

Also, the varta battery? Is there a modern day replacement?

Thanks!
 
That +12 does seem low, but everything else is spot on. With a low +12, you might experience some issues with peripheral cards, but otherwise your IIGS should run perfectly fine with this PSU. Personally, I'd recap it. There are indeed RIFA's in these PSU's (four of them).

If your battery is the axial lead type, you can replace it with this (https://www.digikey.com/en/products/detail/tadiran-batteries/TL-5101-P/512505), or install a 1/2AA holder and a drop-in battery (https://www.digikey.com/en/products/detail/tadiran-batteries/TL-4902-S/2091932). I suppose you could look into a CR2032 replacement solution as well.
 
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Keep in mind that power supplies for non-precision applications are commonly spec'd for +/- 5%, but your +12 supply does seem a bit low. However it could rise byproduct of keeping the +5 supply regulated under a load. If you had several internal hard drives mounted you'd definitely want it to be closer to 12 V.
 
Under load I get...

-4.94, -12.01, 11.39, 5.00

So pretty ok. What has me sort of freaked out is when I turn the power off, I hear a high pitched sound for a split second. Almost sounds like a cap charging just it happens when power is turned off. Normal?
 
So pretty ok. What has me sort of freaked out is when I turn the power off, I hear a high pitched sound for a split second. Almost sounds like a cap charging just it happens when power is turned off. Normal?
Yes, that is normal.
 
Hey all! Up and running! Original caps. But I notice that the green slanted LED is pretty dim compared to the one on the monitor and when the disk drive seeks, it dims in sequence. Don’t remember that from 4th grade computer class.

Power supply needing a cap kit for sure?

Do the kits from console5 come with tantalums as well as electrolytics?

Thanks!

~Tim
 
Yep! Got it “almost” back together. Minus the monitor. Having it on the bench and running while I cleaned up I head a “pop”. Immediately I ran over and unplugged it. Upon inspection, yep a rifa popped. Where should o buy some new caps? The power supply is sitting on my garage workbench to keep the stink out of my house.
 

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Suitable replacements are available at places like Mouser and Digikey among others. While you have it open examine the electrolytics for bulges or leaks.
 
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