(sniff-sniff) Do you smell smoke?

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Bill Epstein

(sniff-sniff) Do you smell smoke?
« on: 7 Feb 2008, 01:26 pm »
I really should pay more attention to seating that rectifier tube.



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hagtech

Re: (sniff-sniff) Do you smell smoke?
« Reply #1 on: 7 Feb 2008, 05:43 pm »
I can't really see, is that a burned resistor or soemthing else?  If resistor, then it should all clean up quite well.  Soak in isopropyl alcohol for awhile and brush.  All that black stuff should come off.  Will look almost new again.

jh

Bill Epstein

Re: (sniff-sniff) Do you smell smoke?
« Reply #2 on: 7 Feb 2008, 08:41 pm »
Yup, resistors make great fuses.

hagtech

Re: (sniff-sniff) Do you smell smoke?
« Reply #3 on: 8 Feb 2008, 04:45 am »
And people wonder why I put them there.

jh

analog97

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Re: (sniff-sniff) Do you smell smoke?
« Reply #4 on: 8 Feb 2008, 04:50 pm »
So, when something like this happens, do the copper lines inside the board fry or do the solder hole-plates pop out?  i.e. are these events usually repairable?  Does the whole board need to be scrapped?  Also, if a tube is not properly "seated", how does the voltage go to ground?  Is this an "arcing"?  What does the autopsy report say about both cause and manner of death?  :(

Bill Epstein

Re: (sniff-sniff) Do you smell smoke?
« Reply #5 on: 8 Feb 2008, 10:23 pm »
The board cleaned up almost 100% with just an inch of exposed copper trace. The sacrificial 220 ohm grid stopper melted.

I guess it wasn't carelessness with the tube (the detent on the Sovtek 5AR4 is kinda vestigial) but something else as the same thing happened when I powered up this AM on the bench. Has to be a short on the hidden side of the board. I was fumbling around in the dark before the first time to re-attach a ground to a tranny bolt and I must have fubar'd something.

Blame it on my advancing Glaucoma: (voice of Jim Backus) "Oh Magoo, you've done it again!" :rotflmao:

Tomorrow, I'll disconnect and lift the board. As we say in construction, 'there's never time to do it right, but always time to fix it'.

Good to have the Nova Phenomena as a back-up, Acoustic Sounds just came to my door: Way Out West, Farmers Market Barbecue and Clifford Brown All-Stars.