Threshold Model FET one - fault

[nellson]

Threshold Model FET one - STASIS Lienear State Pre-amp.
My Pre-amp has failed today and continualy blows fuses now.
Has anyone had a similiar problem or known suspect components, or anyone have a schematic of the power supply?

regards

Richard

 

[Nelson Pass]

Power supply capacitors would be the first thing I would
replace, and also all the tanatalum and electrolytic power
supply decoupling capacitors on the boards.

 

[nellson]

Main filter caps replaced and all decoupling caps replaced with elna cerafins. Checked all power supply diodes bridge etc, the 2 Stasis transistors in power supply and measured all film caps as ok.

Problem still occurs and blows main fuse on power on, Anyone seen similar fault before on FET-1 or schematic of the power supply?

Thanks on help so far

 

[johndiy]

you have some sort of short circuit check main amp
module

regards

 

[apassgear]

Not very likely but you may have a short on the primary of the power transformer especially if the fuse blows immediately after you turn on the preamp.

Check with an ohmmeter and see if you have some resistance and not a short.

 

[johndiy]

to really see if thats the case disconnect the secondaries
and switch on

regards

 

[nellson]

Special thanks to everyone for there help. This is the first time i have found a transformer failure. All new elna Cerafins replaced in the amp. The fault ended up being the transformer. All is now working fine and the 500ma fuse is rock solid.

Thankyou

Transformer specs are:
AVEL-LINDBERG
15VA Toroid Transformer (encapsulated)
Type 40/3034
Max load 7.5A per winding
primary has 2 * 115v windings
secondary 0 20v 0v 20v

Still Available from:

47 South End Plaza
New Milford, CT 06776
860-355-4711, ext 41
fax 860-354-8597
www.avellindberg.com $65 US