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Title: More strange noises & wild bias fluctuations... Post by: Mitch on July 31, 2008, 07:04:39 AM Guys-
got my tech working on this (he's now registered as a Ceriatone Tech for the south of the UK- see Nik's site for details) but any help would be greatly appreciated. After an hour or so use my Overtone makes strange 'popping noises' and ONE o/p tube's bias suddenly goes off to the stratosphere & then blows the HT fuse! In fact yesterday one tube measured 28ma while the other was 65ma+ !!! :o It's not the tubes, they've been changed three times. Gonna get a can of freeze spray today and get it on the bench and see what happens. Just wondered if anyone else has had these issues??? ??? Title: Re: More strange noises & wild bias fluctuations... Post by: casken on July 31, 2008, 02:27:30 PM Please do keep us posted. A few days ago mine starting making popping noises. It is rare (maybe twice or so when playing for 30 mnutes to an hour) and I had assumed it maybe was a tube going south. My amp is only a few weeks old.
Title: Re: More strange noises & wild bias fluctuations... Post by: mcinku on August 01, 2008, 06:14:48 AM Sorry to hear about your amp and unfortunately I can't help, I have no clue what might be going on but definitely keep us posted. We can all learn from things like that. :( Title: Re: More strange noises & wild bias fluctuations... Post by: Mitch on August 01, 2008, 12:26:29 PM Guys-
Mystery over!!! :chairdance: - My tech & I decided the problem had to be in the bias pot area & even before we fired it up on the bench as an afterthought I gave the two resistors from the negative bias probe a gentle yank & low & behold- one had a totally dry joint at the tube socket terminal end- in fact it popped right out with hardly any effort! This would explain the weird bias fluctuations & noises... No disrespect to Nick & his team- this could happen to anyone's solder work- especially as the amp has been bounced around in the back of my car on gigs & not forgetting the 3000 mile journey from Malaysia to the UK! So check for dry joints in this area if your OT makes similar 'frying & popping' noises - it's especially vulnerable here due to the heat rising through the chassis from the O/P tubes. I'm a very happy man again- in the nick of time too as I was about to break out the old Crate VC50 from the garage for tonight's gig! ;) :D ;D Title: Re: More strange noises & wild bias fluctuations... Post by: mcinku on August 01, 2008, 04:57:19 PM Great...
...thanks for reporting back ;) Title: Re: More strange noises & wild bias fluctuations... Post by: casken on August 03, 2008, 12:58:52 AM Mitch, glad you have a happy ending. Mine will be as well but its gonna take a little longer, I am afraid.
My power transformer went totally ker plunk and ker pluey, bad part. The tech said it didn't appear to have overheated, it just died. Nik's been right on top of it and a replacement will be sent Monday. Mystery solved, although amp is currently out of commission :'( ...just as we were getting to know each other. |