Trace Elliott help.

[YouMa]

Hello can any trace buffs give me an idea where to start? I managed to get a GP7 SM head and a Trace 15 inch cab for 40 quid,only trouble is the head lights up etc and it seems like the transformer inside powers up but no sound,i noticed when i switch it on the fan does not start but if i push it,the fan starts.The inside is immaculate and it was working up until a few weeks ago,(its my drummers mums old amp). I know a bit about soldering and components but not loads. Is there a common fault on these amps? I would appreciate any ideas,I will award a large bag of haribo kiddies mix to the person who provides a solution,hope you are all well.

[Matt P]

afraid i can't give you any pointers but i can recommend the guy who sorted my trace (very early gp11) Jez at Arkless electronics in Bedlington (i'm guessing that magpie land is local to me!), did a great job.

Matt

[kaygee]

I have seen something similar on a TE amp before. The amp may have overheated due to the fan not working.
In my case spinning the fan by hand, with the power off, forwards and backwards got rid of the gunk that stopped it spinning and replacing a couple of blown fuses got it working again. I hope yours is as easy to fix too.

[vax2002]

They were the amps that just about broke Trace Elliot, if you had a bad one, they rarely stayed working for long and often mid gig was it's chosen time.
I once had a hnc tech from a university look at mine and his opinion was someone in design had misclaculated the voltage in in pre-output stage and the problem woul re-occur constantly.
With that I dump it.
It was replaced with a white front peavey fire bass 10 years ago, that just works week in and week out.

Edited April 12, 2012 by vax2002

[YouMa]

Opened her up and found circuit board blackened underneath a 1k resistor,but.......when i multimeter it its value is still showing around 1k could this be the problem,anybody?

[VTypeV4]

I had a 300SM which exhibited similar -but not quite the same- symptoms and the faults in mine were two fold:

A: Faulty Transistor which controlled the fan
B: Faulty/sticky relay which 'connects the output stage' when un-muted

I seem to remember it costing about £15 to fix.

This amp had the (in)famous BiPolar Bear output stage which I know can be at best troublesome and I expect yours will be the same. The one in my old 4808 combo fried up so I replaced with the later Clive Button model which can be indentified by the single large heat sink rather than two smaller ones.

If you go down this road, make sure you use heat compound on the output devices and also fan control transistor or it'll get red hot and shut itself down. I never had an ounce of grief with it in over ten years of use.

Good luck!

[Mr. Foxen]

[quote name='YouMa' timestamp='1337034801' post='1654546']
Opened her up and found circuit board blackened underneath a 1k resistor,but.......when i multimeter it its value is still showing around 1k could this be the problem,anybody?
[/quote]

Find what that resistor attaches to, and that will likely be what is wrong. I'd guess a transistor that has died and drawn more through the resistor than it can take. Although working resistor and blackened board suggests it has been replaced, or its an adjacent one that has exploded.

[YouMa]

Cheers lads.