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Title: OTS PT gone? Post by: Fred.T on February 24, 2010, 04:57:31 PM Power On amp (on standby) and there goes fuse. Amp was working fine for several months, I assembled it myself.
I disconnect all the wiring from PT except PINK (220V) to switch and Black (0) that goes to mains input Power On - fuse burned again. I measured the resistance between taps but not sure what should I expect, transformers are not my cup of tea so to say. Please any knowledge/advice is greatly appreciated, what measured values should I expect between taps (with the transformer disconnected of course), 0's, grounds (E) to to be sure that is something wrong with the PT. Except it's blowing fuse every time :-) One more - I was using Fast blow fuse instead of SLow blow, didn't have any at home, but if the tran is OK that shouldn't matter that much, right? THANKS!! Title: Re: OTS PT gone? Post by: ODME on February 25, 2010, 12:46:13 AM Power On amp (on standby) and there goes fuse. Amp was working fine for several months, I assembled it myself. I disconnect all the wiring from PT except PINK (220V) to switch and Black (0) that goes to mains input Power On - fuse burned again. I measured the resistance between taps but not sure what should I expect, transformers are not my cup of tea so to say. Please any knowledge/advice is greatly appreciated, what measured values should I expect between taps (with the transformer disconnected of course), 0's, grounds (E) to to be sure that is something wrong with the PT. Except it's blowing fuse every time :-) One more - I was using Fast blow fuse instead of SLow blow, didn't have any at home, but if the tran is OK that shouldn't matter that much, right? THANKS!! I wouldn't count on anything but trying it with a slow blow. However, if you disconnected all the secondaries from the circuitry, so that the only connection to the transformer is the AC, and it still blows (with the correct fuse) - then the transformer is bad. Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 07:26:26 AM My friend had an issue like that and PT was gone...
I got a new PT from Nik and at that time I measured both, just to see where the issue was. In my case it was 345-0-345 tap which went bad. See the picture attached... BTW this PT is for 50W amp... Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 07:31:27 AM BTW when I received new PT I noticed it was bigger than the original one. Nik told me they improved the PT since they started with OTS...
You can see the picture here... http://ceriatoneforum.com/index.php?topic=1463.msg10250#msg10250 (http://ceriatoneforum.com/index.php?topic=1463.msg10250#msg10250) Title: Re: OTS PT gone? Post by: Fred.T on February 25, 2010, 08:42:24 AM Thank you all!
This chart is exactly what I needed. On the PT there is a sticker saying 3/12 07 so I guess it's the older one. Only thing that worries me is why it went bad. Must check everything in the amp.. Any suggestions what can/could cause PT goes bad, or it can be just bad PT Anyway,THANKS!!!! Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 09:58:02 AM In this case nothing else was wrong just the PT.
I don't know what caused this, perhaps a voltage surge can cause this. ??? ...anyway, after I fixed the amp for my friend, I ordered a power conditioner for my amps. I don't know if this is helping but at least it feels better ;D (http://freeweb.siol.net/mcinku/images/guitars/Rack.jpg) Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 09:58:44 AM Forgot to say...
... let us know which part of the PT went bad ;) Title: Re: OTS PT gone? Post by: Fred.T on February 25, 2010, 12:21:32 PM It looks like 345-0-345 is fried. But have to check with more precise DMM.
And, since the amp is on desk, it's time for mods and tweaks :-) This is a 50watt stock OTS built according to Nik's layout from last year. I guess I will try tweaks you posted in: http://ceriatoneforum.com/index.php?topic=1000.msg7198#msg7198 I'll first try with bigger caps on Power stage (mine are still 100uF and on latest Nik's layout is 200uF) then FET will be out and replaced with the Deep switch pre OD pot to the back ... Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 12:29:46 PM Enjoy your "tone quest".
;) Title: Re: OTS PT gone? Post by: Fred.T on February 25, 2010, 12:32:20 PM BTW, you're my neighbor, sused.
I am in Zagreb :-) Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 12:39:42 PM BTW, you're my neighbor, sused. I am in Zagreb :-) ;D Ako trebaš kakvu pomoč samo javi. ;) Title: Re: OTS PT gone? Post by: Fred.T on February 25, 2010, 12:43:10 PM Genijalno, a ja lutam po svetu. ;D
Lep pozdrav, sosed! Title: Re: OTS PT gone? Post by: bluesfendermanblues on February 25, 2010, 01:18:18 PM Nice greetings, to both of you 8)
Title: Re: OTS PT gone? Post by: mcinku on February 25, 2010, 02:41:35 PM Nice greetings, to both of you 8) ;D Sorry for this local thingy... Title: Re: OTS PT gone? Post by: Fred.T on February 25, 2010, 05:38:01 PM I guess it wasn't so bad, just exchanging hello's on local familiar language. Hope we won't get punished by Forum Authorities.
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