exxos's Atari, Amiga & retro forum

exxos wrote: ↑Fri Oct 26, 2018 7:18 pm Some caps "back in the day" were the size of coke cans, replacements like 5% of the size...

bi-polar caps though ? Wonder why... I probably would have just stuck a polyester in it instead

Well, let's just try it then. Looks a bit lonely though, such a small cap in such a big place (the circle on the PCB is as large as my thumb).

I have absolutely no idea why bi-polar, the 1084-D2 I recapped yesterday didn't have one but the design was quite different as well. Different manufacturer I think, lots of signs of that (different par number encoding schema, different pcb symbol style etc.)

Looks really lonely... please don't explode

sandord wrote: ↑Fri Oct 26, 2018 7:27 pm Looks really lonely... please don't explode

YIKES!

I just finished recapping the 1084S-P2 and powered it on. Perfect picture! Ultimate stability!

And then...

I heard a popping/hissing sound

I rushed to pull the plug (the powerbutton is broken as usual with these devices).

The funny thing is that I didn't smell anything odd, which usually is the case when something is burning. A quick inspection didn't reveal anything suspucious. Neither any smoke was visible.

The one thing that crosses my mind is the suction cap that connects the tube to the line transformer, I had a little trouble reconnecting it properly. Though the leads are in the tube hole, the suction cap my be just a little not-so-tightly-connected. Could it be that I heard sparks from underneath there?

Obviously I checked the bipolar cap but it looks okay. I haven't measured anything yet, not even sure how to do that.

Some more observations:

- the picture didn't turn bad or anything when I heard the sound
- a cable with an interference suppressor on it * MIGHT * have touched some parts on the pcb, so perhaps that was shorting something
- I'm afraid to turn it on again

sandord wrote: ↑Fri Oct 26, 2018 10:24 pm The one thing that crosses my mind is the suction cap that connects the tube to the line transformer, I had a little trouble reconnecting it properly. Though the leads are in the tube hole, the suction cap my be just a little not-so-tightly-connected. Could it be that I heard sparks from underneath there?

You can lift the cap up with a screwdriver (BUT insulated handle as it could be charged to like 30KV!) and check its inserted correctly. We use to wire a screwdriver to the gnd strap and poke under the cap to discharge it before checking or removal.

exxos wrote: ↑Fri Oct 26, 2018 10:44 pm You can lift the cap up with a screwdriver (BUT insulated handle as it could be charged to like 30KV!) and check its inserted correctly. We use to wire a screwdriver to the gnd strap and poke under the cap to discharge it before checking or removal.

I've rocked the cap with a well insulated heavy plier and I'm sure it's connected firmly.

Perhaps I should just turn it on for a few more seconds and see if I can see anything if the sound comes back. Hopefully not a spark

sandord wrote: ↑Fri Oct 26, 2018 10:49 pm I've rocked the cap with a well insulated heavy plier and I'm sure it's connected firmly.

Perhaps I should just turn it on for a few more seconds and see if I can see anything if the sound comes back. Hopefully not a spark

If you can turn on via extension cable, and look at the rear and power up, you can see in almost dark if anything is arcing inside or not.

exxos wrote: ↑Fri Oct 26, 2018 10:58 pm If you can turn on via extension cable, and look at the rear and power up, you can see in almost dark if anything is arcing inside or not.

Good advice!

I just did that. The monitor has been running for minutes now and nothing seems wrong. So it must have been the inteference suppressor causing a short on the PCB. I tied it up higher to avoid that from happening again.

Could be be a "singing inductor" ? Those things can hiss/squeal and make a right row...