Photos of My Leaky SE/30 Capacitors

[trag]

I don't know if you can actually tell that they're leaking in these photos. I am not much of a photographer.

I was preparing to put my four pre-SE compacts (512K X 2, Plus X 2) in the attic and realized that I had a pair of SE/30s up there from which I couldn't remember if I had pulled the batteries. These are different from the two I mentioned a while back.

So up into the attic. Sure enough, they both have batteries installed. Happily, neither of them has leaked. One battery had an '88 date code. But looking at the logic board, the dust was clearly sticking to the boards more around the caps, indicating sticky leakage. One of boards has clear corrosion of the pins and solder in the vicinity of the caps. It's amazing to me how far this stuff apparently migrates.

So I pulled all the caps and cleaned the boards. These pics are just from before pulled the caps and cleaned the boards. It was too late and I was too wiped afterwards to take more pictures. I didn't lift any pads though. Patience. Lots of patience and even more solder flux.

If you look closely, you can see evidence of corrosion on the solder on the pads for the caps. The later pictures show the dirtier board which also has a good bit of pin corrosion.

Speaking of solder flux, my experience last night was that removing the caps often used two or three times as much flux as I expected. I wonder if the dust on the board was somehow using up the flux when I heated it. Anyway, point being, if it's taking a long time for a cap to come loose. Consider stopping, remove the soldering pencils, and liberally apply more flux to the cap terminals.

And never, never grind the pencil tip into the pads or cap trying to make it heat faster. I know I have this impulse, but it's the quickest way to a torn or lifted pad. If it's not heating, pressing down harder is not the answer. There's something else going on. Re-tin your solder pencil tip. Apply more flux. Sometimes applying fresh solder to the part being removed will actually make it come off more easily. But don't grind.

Note on the picture below and following, how there seems to be thicker dust in the vicinity of the caps. This is from the dust getting stuck in the sticky cap leakage.

 

[Unknown_K]

How hot does an attic get in Texas during the summer, how is the humidity? I think quite a few problems people have is baking and freezing machines in non climate controlled storage in areas that have big temperature swings.

Luckily SE/30's are not that hard to recap (like classic 2's) since you have space to get the soldering iron where it needs to go.

 

[trag]

The attic gets very hot in the summer, but I doubt if it ever freezes up there. It rarely freezes, even outside. Perhaps three times a year the temperature dips below 32 for a few hours outside. In the attic it's probably several degrees warmer.

Last year we actually did get snow that stuck. The temperature dropped so fast that between the time I left for work when it was in the 50s and when I got home, a couple of the plants on the deck were frozen. But that's incredibly rare.

I agree the heat in the attic isn't ideal, but there's just not that much storage space available in the house.

 

[Unknown_K]

I understand, without a huge basement I wouldn't have much of a collection. Most people store stuff in their garage (and we have a pretty big garage), but without climate control electronics would go through some nasty temperatures from freezing to boiling over the course of the year (plus humidity).

 

[phreakout]

Trag,

Sorry to go off topic, but what's with all the ICs scattered about in that last pic? I think they'd be much more safe inside an anti-static bag or that special type of black foam. Ugh!

73s de Phreakout. :rambo:

PS: Will PM you soon on something completely different.

 

[techknight]

Well the problem with climate, is itll eventually cause semiconductors to fail. Obviously epoxy absorbs moisture (it tries to escape if heated too fast, causes popcorning). And this will eventually make its way to the chip die, oxidizing/corroding it, killing it.

So its probably a good idea to bake the board for a little while every once in a great while, to keep moisture out of the board, and ICs.

 

[trag]

Trag,
Sorry to go off topic, but what's with all the ICs scattered about in that last pic? I think they'd be much more safe inside an anti-static bag or that special type of black foam. Ugh!

Certainly not ideal, I agree. However, in a bag, they'd be in a big jumble in a bag. On my desk, you can't see it very well, but they're sitting on a bit metal plate, which I use for static control.

Tubes would be the thing, if I had tubes for that size chip...

So big jumble in a bag, or big jumble on a large metal plate. Of course, I never intended it to end up like that. I got to the point where I had carefully organized rows and columns of chips and circumstances overcame me and I never made it back to that project. Over time, carefully aligned rows and columns became a big jumble....

I guess I could post time elapse photos and label it as an Entropy In Action presentation.