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Title: 1987x blowing HT fuses Post by: Brother_Budro on April 16, 2009, 07:54:35 PM I've had my 1987 for almost 2 years and a few months ago the power transformer blew and i got a new one (it was either the power or output i can't remember)
then recently it started blowing ht fuses to the point where everytime i turn it on it blows them and i can't play my amp it has been to the tech and he has no idea what is wrong with he he said he plugged it up to his cabinet and it worked fine i can plug my amp into other cabs and it doens't work and i can plug other amps into my cab and that works any ideas, it's starting to get really old thanks guys Title: Re: 1987x blowing HT fuses Post by: cmoore on April 17, 2009, 12:23:44 AM I'm not the best guy to be helping you with this, but here it goes. For me, or anybody else including you, it is important to know which one of your transformers "blew" and why. Off the top of my head I would say you have a bad power tube. But you could also be looking at a bad PT, filter cap, or even diodes in the rectifier circuit. Are you sure you have a "Slow Blow" fuse for the HT ? Do you know how to build a light bulb limiter? Do you have a copy of Gerald Weber's book? He has a pretty good routine for checking fuse problems.
Title: Re: 1987x blowing HT fuses Post by: Brother_Budro on April 17, 2009, 04:17:35 AM the HT doesn't have slow blow fuses because i havne't found them in 500mA
i really can't remember which tranny blew i want to say PT Title: Re: 1987x blowing HT fuses Post by: cmoore on April 17, 2009, 04:40:12 AM I am pretty sure Hoffman sells Slow Blo 1/2 amp. If your PT burned up it is possible it took something else with it. It very easily could have stressed a tube or filter cap. That part may work for a while, but fail later. Who replaced the Out Tranny? They may be able to give you some guidance.
Title: Re: 1987x blowing HT fuses Post by: Brother_Budro on April 17, 2009, 03:11:27 PM it has been at my amp tech's
he said once he replaced the fuse everything worked fine and he jammed with it for a while. got it to my place and it blows them like no tomorrow my tech thinks it's something to do with the speakers but i can't see any problems there was a bridge (two wires connecting terminals) from one input jack to the other but i cut that the amp worked right after i cut it but not anymore Title: Re: 1987x blowing HT fuses Post by: Kitarist on April 20, 2009, 08:40:09 AM Are you using speaker cables? i had the same problems man it was at the tech too and he had no problems until i realised that i was using some cheap cables that werent made for speakers.
Title: Re: 1987x blowing HT fuses Post by: Brother_Budro on April 20, 2009, 07:24:10 PM http://accessories.musiciansfriend.com/product/Monster-Cable-Standard-S100-14-14-Speaker-Cable?sku=331640
that's the speaker cable i'm using and i used the same one when i ran a different amp through the same cab Title: Re: 1987x blowing HT fuses Post by: cmoore on April 21, 2009, 04:56:56 AM it has been at my amp tech's \\he said once he replaced the fuse everything worked fine and he jammed with it for a while. got it to my place and it blows them like no tomorrow my tech thinks it's something to do with the speakers but i can't see any problems there was a bridge (two wires connecting terminals) from one input jack to the other but i cut that the amp worked right after i cut it but not anymore Sounds like all you did was cut the parallel connection between the two out jacks. That shouldn't be a problem unless something is shorting out somewhere. ( Pictures? ) Have you played your amp anywhere other than your house? Can you take your amp to a friends house and try it there? Something is not right with this story. If it does not blow fuses at your techs shop...... You either have line problems at your house, or there is a piece to this puzzle that we are being denied. Title: Re: 1987x blowing HT fuses Post by: Brother_Budro on April 21, 2009, 02:24:56 PM what i cut was just what looked like a bridge between the two jacks in the speaker cab
but one of them has never worked so i just figured those could have been shorting out something so when i cut it i re-fused and tried it again and it worked (at my house) so then i packed my amp up and came down to uni so my band down here was practicing i plugged my amp up nothing keeps blowing fuses |