68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.

PowerBook 180 completely shorted

Posted by: fluxtransistor on 2022-07-19 23:19:23 So I just picked up a new 180 which had quite a bit of battery corrosion inside of it. However, after thorough cleaning, I’m still getting a short circuit on the main DC input jack (with everything unplugged from the motherboard). + to - reads 3 ohms. I’m conparing this to a dead 170 board I have around which reads several hundred K. If there’s a shorted line somewhere, I can’t find it! Please help.

Posted by: fluxtransistor on 2022-07-20 00:15:39 Update: photos. I may have been too dramatic about the corrosion, looking at some other posts here it seems minor.

Posted by: fluxtransistor on 2022-07-20 02:23:55 Curiously, the resistance across three adjacent components - C51, D15, C69 by the power jack on the underside of the board - is the same 2.5 ohms I’m getting across the jack. Does anyone have a 180 board to compare this to?

Posted by: fluxtransistor on 2022-07-20 06:23:09 My intuition led me to desolder the D15 diode, which turned out to be blown. I’ve replaced it with a similar looking one from the PB170 board (which died after I fried a MOSFET). Updates when I reassemble the machine, but the board is looking good with a healthy resistance in the megaohm range.

1