Monitor recapping and low ESR

[sandord]

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.)

[sandord]

Looks really lonely... please don't explode

IMG_20181026_202417.jpg (139.84 KiB) Viewed 6561 times

[exxos]

Looks really lonely... please don't explode

[sandord]

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.

[sandord]

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

[exxos]

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.

[sandord]

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

[exxos]

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.

[sandord]

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.

[exxos]

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