Uncreative Labs

Joined: 01 Oct 2004 Posts: 169 Location: behind you!

First off hello. It's been a while. Shocked

I have decided to bring a lot of my old computers out of storage, and after 10 years of sitting there are some issues (and some casualties). Embarassed

I plugged in a Compaq portable 286 and when I turned it on there was a loud bang, followed by a lot of reddish smoke. Turned out a tantalum detonated. I need to replace it, but because tantalum capacitors obliterate themselves when they go, I have no clue to it's value. Is there a schematic available somewhere? It was one of the larger radial style caps along a row of electrolytic capacitors.

Posted: Thu Feb 21, 2019 10:13 pm

Welcome back! I had you figured for "Internet dead".

Joined: 01 Oct 2006 Posts: 36 Location: USA

Ah, the magic smoke. I couldn't find a schematic for it but if it helps the part number for the power supply in the Portable 286 is 102818-001. I'm guessing that's where the cap blew. Here is the maintenance and service guide for it if you don't have it already, unfortunately it doesn't have any schematics. I'll keep an eye out though. http://www.minuszerodegrees.net/manuals.htm#Compaq

Joined: 02 Oct 2004 Posts: 594 Location: Western NC

harshbarj wrote:

I plugged in a Compaq portable 286 and when I turned it on there was a loud bang, followed by a lot of reddish smoke. Turned out a tantalum detonated.

I gather this was in the P/S section? Any idea what was the reference designator on the board (C1, C13, etc.)

Joined: 01 Oct 2004 Posts: 169 Location: behind you!

T-R-A wrote:

harshbarj wrote:

I plugged in a Compaq portable 286 and when I turned it on there was a loud bang, followed by a lot of reddish smoke. Turned out a tantalum detonated.

I gather this was in the P/S section? Any idea what was the reference designator on the board (C1, C13, etc.)

It was.
It was c16. About half the cap is gone. The other caps of the same size are all 25V 68UF, so it's likely this one was also that kind. I'm likely to fully recap this psu other than the large electrolytic caps (made by sprague).