Mac OS 9 Lives

Classic Mac OS Hardware => General Hardware Discussions => Topic started by: FBz on May 27, 2022, 04:23:40 PM

Title: AcBel MDD PSUs (again)
Post by: FBz on May 27, 2022, 04:23:40 PM
Outside of only one slightly swollen capacitor (C60 - I think)…
(& I know that the caps can’t be judged on appearance alone.)

(http://macos9lives.com/smforum/index.php?action=dlattach;topic=4088.0;attach=4769;image)

This resistor, R31(?) looks as if it has been a-ho-lotta-hotta. In fact, baking its’ normal black plastic covering mostly off. Nearly all of the AcBel PSUs that I’ve opened, also exhibit a high-heat appearance here and I wonder about simply replacing it… and maybe with a resistor of slightly different value?  300W AcBel pictured here.

(http://macos9lives.com/smforum/index.php?action=dlattach;topic=6334.0;attach=10102;image)

The board bottom view tells an additional story as the R31 connections have separated from the PCB (from the heat?).
(And what’s with the one, different leg pictured - without any solder?)

(http://macos9lives.com/smforum/index.php?action=dlattach;topic=6334.0;attach=10104;image)

Anyway, will contact Andy to see if I can pick his brain?
If not, well… some AcBel PSUs may be sent his way very soon.

And here’s a 400W AcBel with C21 domed and leaking - and C60 also top swollen.
This one still boots & runs a 1.42 GHz MDD but requires unplugging & re-plugging to outlet to then boot / run.

(http://macos9lives.com/smforum/index.php?action=dlattach;topic=6334.0;attach=10106;image)
Title: Re: AcBel MDD PSUs (again)
Post by: IIO on May 27, 2022, 06:49:00 PM
horrible. and i thought the previous models PSU was difficult to disassemble.
Title: Re: AcBel MDD PSUs (again)
Post by: peeperpc on May 28, 2022, 10:02:51 AM
I replaced the R31 (360W Acbel PSU) with a Panasonic ERG-3SJ203 (20 kOhms ±5% 3W Through Hole Resistor Axial Flame Proof, Safety Metal Oxide Film).

No idea about that no solder leg, though.
Title: Re: AcBel MDD PSUs (again)
Post by: FBz on May 28, 2022, 10:32:21 AM
Thanks @peeperpc. Will give that a go on the next rain day here.
(Along with some cap replacements.) ::)
Title: Arrow Electronics
Post by: FBz on June 27, 2022, 07:12:50 AM
Well, the Panasonic ERG-3SJ203 resistors have arrived. Mouser and Digi-key noted them as unavailable & discontinued - but Arrow Electronics (Centennial Colorado) had seven remaining in stock so I bought ‘em all. And @ .08571 each that came to a whopping sixty cents. With tax, I think the grand total was eighty cents!

AND Arrow currently offers free shipping for the first two orders from new accounts - so I will be checking with Arrow Electronics for any future needs. Nice to now have another source other than just Mouser or Digi-key.

Now if I only had the time to install / test these! ;)