Forte Model 1 needs new toroid transformer I think...

cuencano · 23rd April 2010, 04:42 AM

I need some help finding out where I can get a replacement toroid transformer for a Forte model 1 that I've had for 5 years but just went out last week.

The whole amp went out, no noise, no light on the led, no humm from the transformer. So I thought it must be something that failed from the toroid to the power plug since those are the only single components. I think if something had failed after these, then most prob only one chanel would had failed. The fuses are all good, as well as the main switch.

With the help of a voltmeeter and a couple of screw drivers I tested continuity starting from the power cord plug up to the toroid transformer. At least to this point all looks good and it is mainly soldered wires. After the transformer, I tested both diode bridges and they did allow current flow in the correct way and did not transfer any current in the oposite direction ... hope that makes some sense...

Then I reasempled everything and with the amp pluged in and switch turned on, tested voltage on the toroid inputs (correctly reading close to 120 volts alternating) and outputs. The outputs are death, the schematic shows which outputs are for the +57 volts and ground (tested at the diode bridges inputs, or fuses) and the toroid is not showing any voltage on the 57V ac side.

So... figured the toroid needs replacing

can't figure out where to get my hands on one though, and to be honest I think I may be doing something wrong. Some help would be greatly apreciated...

Thanks,
Norberto.

cuencano · 23rd April 2010, 05:03 AM

Would this be a good replacement :

Parts-Express.com:Avel Y236905 800VA 60V+60V Toroidal Transformer | TRS transformers transformer toroidal transformer toroidal toroid mounting kits kit gauge copper avel

?

cuencano · 23rd April 2010, 08:06 PM

help please !!

Nelson Pass · 23rd April 2010, 08:28 PM

I recall that the Forte 1 was rated at 50 watts, which means
that it wants to swing +/-28 volts. Allowing for a few volts
loss in the circuit, we can imagine maybe +/-33V. You can
get this from dual 25V secondaries. 60V secondaries would
be way too much.

cuencano · 25th April 2010, 03:43 AM

Thanks a lot, I found a used transformer from a model 3 that I belive is the same one used in the Model 1.

23rd April 2010, 04:42 AM	#1
cuencano diyAudio Member Join Date: Nov 2003 Location: Atlanta	Forte Model 1 needs new toroid transformer I think... I need some help finding out where I can get a replacement toroid transformer for a Forte model 1 that I've had for 5 years but just went out last week. The whole amp went out, no noise, no light on the led, no humm from the transformer. So I thought it must be something that failed from the toroid to the power plug since those are the only single components. I think if something had failed after these, then most prob only one chanel would had failed. The fuses are all good, as well as the main switch. With the help of a voltmeeter and a couple of screw drivers I tested continuity starting from the power cord plug up to the toroid transformer. At least to this point all looks good and it is mainly soldered wires. After the transformer, I tested both diode bridges and they did allow current flow in the correct way and did not transfer any current in the oposite direction ... hope that makes some sense... Then I reasempled everything and with the amp pluged in and switch turned on, tested voltage on the toroid inputs (correctly reading close to 120 volts alternating) and outputs. The outputs are death, the schematic shows which outputs are for the +57 volts and ground (tested at the diode bridges inputs, or fuses) and the toroid is not showing any voltage on the 57V ac side. So... figured the toroid needs replacing can't figure out where to get my hands on one though, and to be honest I think I may be doing something wrong. Some help would be greatly apreciated... Thanks, Norberto.

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23rd April 2010, 05:03 AM	#2
cuencano diyAudio Member Join Date: Nov 2003 Location: Atlanta	Would this be a good replacement : Parts-Express.com:Avel Y236905 800VA 60V+60V Toroidal Transformer \| TRS transformers transformer toroidal transformer toroidal toroid mounting kits kit gauge copper avel ?

23rd April 2010, 08:06 PM	#3
cuencano diyAudio Member Join Date: Nov 2003 Location: Atlanta	help please !!

23rd April 2010, 08:28 PM	#4
Nelson Pass The one and only Join Date: Mar 2001	I recall that the Forte 1 was rated at 50 watts, which means that it wants to swing +/-28 volts. Allowing for a few volts loss in the circuit, we can imagine maybe +/-33V. You can get this from dual 25V secondaries. 60V secondaries would be way too much.

25th April 2010, 03:43 AM	#5
cuencano diyAudio Member Join Date: Nov 2003 Location: Atlanta	Thanks a lot, I found a used transformer from a model 3 that I belive is the same one used in the Model 1.