Is it possible power supply was set for 110V not 220V? I do not believe it's the TR4-although of course it could be. If it was, I should think you would have lost a diode(s) or Heaven-forbid: the transformer. It could have been a faulty diode that caused it-hence, after making sure about the input voltage selector (and if it's correct, I'd check its wiring) I'd check all the diodes.
Finally, it's always possible it was just the capacitor's time having come. If you've made sure about the voltage setting, then replace the cap, do the same start-up routine, and then the SAME cap goes, then yeah, it's obviously not the caps, but something else going on. Before you walk-away for the run-time test, I'd check all the voltages just to be sure they're right. That way, if it does go again (or some other cap) you'll know at least it LOOKED right prior to catastrophe. Ed Tanton website: <http://www.n4xy.com/> http://www.n4xy.com All emails <IN> & <OUT> checked by Norton AntiVirus with AutoProtect -------------------------------------------------- Wag more / Bark less -------------------------------------------------- From: drakelist-boun...@zerobeat.net [mailto:drakelist-boun...@zerobeat.net] On Behalf Of Damien Mannix Sent: Thursday, August 23, 2012 12:24 PM To: drakelist@zerobeat.net Subject: [Drakelist] Exploding cap' ??? Hi all, Bought an immaculate looking TR4 which has been out of use a long time. Also bought an AC4 which claims to have had the original EHT caps and diodes replaced. Powered them up with 20 vac for four hours, then up in 20 v steps at four hours per step, listening and sniffing for any problems. Reached 220 vac an hour ago. AC4 slightly warm and centre of TR4 top a bit warmer. Then there was one hell of a crack! Sounded like a gunshot and frightened me to death! Swiched off immediately of course. No smell that I can detect. Is that what an exploding capacitor sounds like? Any advice on where to start looking? The TR4 or the AC4? Sad day for me. Trying to return to the hobby after over 30 years. Been too busy making a living and bringing up a family. Regards, Damien G3XER
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