Magic Smoke - Magic Goo?

nathanm · « **on:** 26 Jun 2004, 07:36 am »

Is there an electronic part that would excrete a clear yellowish goo, a capacitor perhaps? My SE-9 amp just blew a tube (and then some I figger) which was kind of exciting to see cause one output tube crackled with purple light for a few moments while Magic Smoke poured out the tube openings in the chassis. Cool. Anyway, upon opening the case, being electrocuted by the high voltages insides, dying, rising from the grave and examining the interior there's a cap with a splatter of this odd substance on the inside top of the case. It reminds me of solder flux kinda. But it does taste quite good, if a bit bitter.

markC · « **Reply #1 on:** 27 Jun 2004, 07:31 am »

Scrape it off and put it in a vial, man. Don't do it all at once or you'll O.D. .... Probabaly polyester or polypropylyene(sp), or whatever the cap is/was made of. At any rate, you should probably try a cheap tube first along with a new cap. Hopefully, you can still make out what value the cap is/was.

djklmnop · « **Reply #2 on:** 27 Jun 2004, 09:36 am »

Do you push the SE-9 pretty hard? I have one too and hope they don't explode, burn down my house and cause sexual frustration.

Andy

djklmnop · « **Reply #3 on:** 27 Jun 2004, 09:37 am »

Quote from: djklmnop

Do you push the SE-9 pretty hard? I have one too and hope it won't explode then burn down my house and cause sexual frustration.

Andy

nathanm · « **Reply #4 on:** 27 Jun 2004, 06:35 pm »

Not at all. I'm using it to drive my 3.0 speakers at my computer. I switched it on and the volume knob was real low. I went to turn it up and suddenly it started smoking and the left power tube flashed and crackled. It continued playing after I switched it off on the right speaker so it doesn't seem to be totally destroyed.

The one EL34 is dead (tested in guitar amp) but it appears to be a cap near that tube which blew up. The only problem is the circuit board is completely trapped by wires. I have to desolder like a dozen wires to get at the damn thing. Although I could possibly yank the bum cap through the tube hole in the chassis. Can you solder a part onto the opposite side of a circuit board from where it normally is?

Looks like Van Alstine's prophecy is true - don't buy tube gear unless you enjoy fixin' it!

(well really, a part could blow up on any amp I s'pose)

Marbles · « **Reply #5 on:** 27 Jun 2004, 06:46 pm »

You know your really rocking when you blow up your computer amp!

lonewolfny42 · « **Reply #6 on:** 27 Jun 2004, 06:55 pm »

Quote from: markC

Scrape it off and put it in a vial, man. Don't do it all at once or you'll O.D. ....

......

......maybe sell it on Agon....

rosconey · « **Reply #7 on:** 27 Jun 2004, 08:02 pm »

i can feel for you nathanm, i killed a tweeter -just ordered a replacement from partsexpress

got too loud with some AC/DC

nathanm · « **Reply #8 on:** 27 Jun 2004, 09:18 pm »

Okay, so I paniced; it looked much harder than it was. I was able to easily desolder the cap without removing anything else. It's an Elna Cap, 63V 220μf. Does that white arrow stripe on the side mean it's polarized by chance? If so, oops - forgot which way it was in there. Doh. The top is bulging and there's magic goo oozed out of it. Let us have a moment of silence for this brave capacitor who gave its life to the pursuit of tube audio.

Red Dragon Audio · « **Reply #9 on:** 27 Jun 2004, 10:01 pm »

Quote from: nathanm

Okay, so I paniced; it looked much harder than it was. I was able to easily desolder the cap without removing anything else. It's an Elna Cap, 63V 220μf. Does that white arrow stripe on the side mean it's polarized by chance? If so, oops - forgot which way it was in there. Doh. The top is bulging and there's magic goo oozed out of it. Let us have a moment of silence for this brave capacitor who gave its life to the pursuit of tube audio.

If this cap was in the audio path, then just look on the other channel as to what direction the cap should be oriented (it is stereo, so they should mirror each other somewhat).

Carlman · « **Reply #10 on:** 27 Jun 2004, 10:03 pm »

Sorry if I'm breaking the silence of the dead cap but, thought I'd suggest you try to find a schematic so you'll know the polarity of the oozing cap.

The problem sounds kind of like a tube failure might have caused the cap to blow, if that's possible... I don't know. Don't listen to me. Take it to a qualified electrical guru and see what they say.... or the manufacturer.. who you'll have to contact anyway to get the schematic.

But, if my uneducated hunch is correct, replacing the cap and tube will put you back to computer hifi bliss. Also, putting the cap in backwards will provide a possible repeat failure or a new, unpredicted fireworks display.

Are things always this exciting at chez Nathan?

Best of luck.

nathanm · « **Reply #11 on:** 28 Jun 2004, 01:31 am »

Yeah the other channel has the same cap so polarilty can be gleaned from that one (if that IS truly what the white arrows mean) so it won't be a problem. I ordered some new replacement caps. If it still blows up I'll have to figure something else out. That's of course the compromise you have to make by buying 'inexpensive' gear produced in far off lands - if it does break getting it serviced at the factory is logistically absurd. Imagine sending this heavy bugger off to Thailand so someone can solder on a capacitor!

Seems insane! Heh!

mgalusha · « **Reply #12 on:** 28 Jun 2004, 03:33 am »

Nearly all electrolytic caps are polarized. The white stripe is almost certainly the negative side. Putting it in with the polarity reversed will provide plenty of entertainment, kind of like a train wreck. If the unit has a PCB it will usually be marked for the positive leg of the cap. Sometimes they use a square solder pad on the positive side.

markC · « **Reply #13 on:** 28 Jun 2004, 03:35 am »

Forget Thailand- get out your soldering iron. A a couple of scrapes out of the old vial and a few inches of solder and you'll be good as new!

nathanm · « **Reply #14 on:** 28 Jun 2004, 04:35 am »

It shouldn't be a big deal, as long as that cap is the ONLY thing which has failed. But then again I said the same thing about replacing a single resistor in my IRD monoblock once...

WerTicus · « **Reply #15 on:** 30 Jun 2004, 01:29 am »

yeah that is a polarised aluminium electrolytic and i do believe the 'stuff' inside it is rather bad for your health so i hope you washed your hands / didnt touch it

if you put it the wrong way it it will explode with eye removing force quiet possibly!

it might be possible to use a bi polar capacitor in its place... and that means you could NOT use an electrolytic and achieve something of an upgrade

nathanm · « **Reply #16 on:** 30 Jun 2004, 02:49 am »

Actually I pried open the cap with a pliers and ate the contents - is that bad? No seriously...whatever goo was in there seems to be safely splattered on the SE-9s interior. The cap itself just has a roll of paper in it... so that's what's in these things! I am pretty confident which way the cap goes in. Maybe someone with an SE-9 could take a picture of theirs for good measure. It's the blue cap to the right of the left channel EL34. The white arrow side was facing towards the rear of the amp.

So what's an electrolytic and how do you know you have one?

WerTicus · « **Reply #17 on:** 30 Jun 2004, 09:41 am »

electrolytics are the cheapest nastiest caps you can get!

they are in all electronics components just about!

they are probably the only type that have a positive and negative one them.

markC · « **Reply #18 on:** 30 Jun 2004, 08:12 pm »

So what's an electrolytic and how do you know you have one?

Every electolytic that I've seen looks like a tin can. Inside, they usually contain paper and electolyte. Like a film and foil where the film is the dielectric and the foil is the conductor, in an electrolytic, the paper is the dielectirc and the electrolyte is the conductor. the spacing between the conductor and the dieletric is what determines the uf value of the capacitor. Well, at least thats the way that I understand it, but I am in no way an expert on this.

WerTicus · « **Reply #19 on:** 30 Jun 2004, 11:38 pm »

its not the space so much as the total surface area betweent the two sides