Threshold Model FET one - fault

nellson · 22nd August 2006, 08:23 AM

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 · 22nd August 2006, 05:23 PM

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 · 7th October 2006, 10:11 PM

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 · 7th October 2006, 10:47 PM

you have some sort of short circuit check main amp
module

regards

apassgear · 8th October 2006, 02:07 AM

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 · 8th October 2006, 02:27 AM

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

regards

nellson · 1st December 2006, 10:49 AM

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

22nd August 2006, 08:23 AM	#1
nellson diyAudio Member Join Date: Jun 2006	Threshold Model FET one - fault 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

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22nd August 2006, 05:23 PM	#2
Nelson Pass The one and only Join Date: Mar 2001	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.

7th October 2006, 10:11 PM	#3
nellson diyAudio Member Join Date: Jun 2006	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

7th October 2006, 10:47 PM	#4
johndiy Banned Join Date: Aug 2006	you have some sort of short circuit check main amp module regards

8th October 2006, 02:07 AM	#5
apassgear diyAudio Member Join Date: Nov 2002 Location: Viña del Mar, Torreon	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.

8th October 2006, 02:27 AM	#6
johndiy Banned Join Date: Aug 2006	to really see if thats the case disconnect the secondaries and switch on regards

1st December 2006, 10:49 AM	#7
nellson diyAudio Member Join Date: Jun 2006	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

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