I need some more information about the Forte4 power amp. Possibly where to find replacement parts, So Once again I come to the forum, Is there a conversion kit to change the multi - voltage input or a Replacement cam that I can buy , I am also wondering, why the Big electrolytic capacitors are wired with 2 of the positive sides to the grounding plate, Any help would be Greatly appreciated, Thanks..
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Because 2 of them are for the positive supplies, and 2 are for the negative supplies.
Thanks for your reply , I am trying to find out about this Amp, SO if you have schematic's or anything like a (Sam's photo facts) about this Amp I would really
Appreciate it, I am Looking for a replacement cam Voltage selector, This was damaged or a 110 volt conversion Method would be helpful.. ?
Appreciate it, I am Looking for a replacement cam Voltage selector, This was damaged or a 110 volt conversion Method would be helpful.. ?
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The damaged voltage selector IEC receptacle is unlikely to be available as a replacement part.
Then the amplifier would have to be custom wired for one particular AC voltage.
This is a dangerous job that is only suitable for an experienced technician.
See if you can locate someone in your area. They would still require a schematic diagram .
Then the amplifier would have to be custom wired for one particular AC voltage.
This is a dangerous job that is only suitable for an experienced technician.
See if you can locate someone in your area. They would still require a schematic diagram .
https://www.diyaudio.com/community/...amp-replacement-transformer-schematic.396620/
Your photo missing the connection plate.
The older style power inlet modules with the rolling CAMs look to be discontinued. You can use this TE connectivity part# PS000S000 as the dimensions are very close to the original part. Mouser has them in-stock #592-PS000S000.
You may need to file the hole slightly. This part does not have the voltage selector built in (better design). You will need to hard wire the transformer to your voltage. I have attached the Forte 1A transformer wiring schematic with wire colors. The color coding should be the same for your amp. Be sure to securely insulate the 100V taps and tie them off (Vio/Wht, Blu/Wht).
Note: The IGBT amps get a bad rap due to device failures. The Toshiba IGBTs have an extreme positive thermal coefficient. This is the main reason for the legacy of blown devices. If the thermal compound has dried out or the device is not torqued down with a belville spring washer, the devices can run hot and eventually run away. This is one of the main causes of failure for many older Forte amps. Early versions did not have belville washers and over time the devices would lose thermal connection to the heatsink. That and the high rail voltages on the Forte 6 amplifiers make them very prone to failure due to shorts across speaker connections or driving very low impedances. It was obviously a marketing decision to try and cram a 200 WPC in such a tiny chassis.
My advice for what it's worth, keep the amp as a 50 watt class A, make sure there are belville spring washers on the outputs and make sure the thermal compound is not dried out.
Good luck.
You may need to file the hole slightly. This part does not have the voltage selector built in (better design). You will need to hard wire the transformer to your voltage. I have attached the Forte 1A transformer wiring schematic with wire colors. The color coding should be the same for your amp. Be sure to securely insulate the 100V taps and tie them off (Vio/Wht, Blu/Wht).
Note: The IGBT amps get a bad rap due to device failures. The Toshiba IGBTs have an extreme positive thermal coefficient. This is the main reason for the legacy of blown devices. If the thermal compound has dried out or the device is not torqued down with a belville spring washer, the devices can run hot and eventually run away. This is one of the main causes of failure for many older Forte amps. Early versions did not have belville washers and over time the devices would lose thermal connection to the heatsink. That and the high rail voltages on the Forte 6 amplifiers make them very prone to failure due to shorts across speaker connections or driving very low impedances. It was obviously a marketing decision to try and cram a 200 WPC in such a tiny chassis.
My advice for what it's worth, keep the amp as a 50 watt class A, make sure there are belville spring washers on the outputs and make sure the thermal compound is not dried out.
Good luck.
No, as OP's transformer only has a single secondary, not dual as shown there....
To clarify, the schematic is from an earlier model, but the wire colors should be the same. I posted the schematic for wire color identification only.
All of the transformers used in the Forte power amps used the same color codes on all 3 of the manufacturers of transformers used in production. Avel-Lindberg, Iskra and Powertronix.
All of the transformers used in the Forte power amps used the same color codes on all 3 of the manufacturers of transformers used in production. Avel-Lindberg, Iskra and Powertronix.
From the previous thread, @Andersonix and the OP's Forte 4 transformer primary winding only have 5 wires and are color coded slightly different.
https://www.diyaudio.com/community/...amp-replacement-transformer-schematic.396620/
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https://www.diyaudio.com/community/...amp-replacement-transformer-schematic.396620/
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I dug around and found the last transformer spec for the Forte 4 & 6 amplifiers. The difference from the Forte 1 transformer colors is the Violet/White 100 Volt tap was removed at some point. I do not think Forte amplifiers were sold much into Japan, so a single 100V tap will give 220-240 Volt operation pre EU harmonization at 230 volts. The Iskra transformers were supplied with a white 100V tap instead of Blue/White used in the Avel and Powertronix parts. I think they used a blue inner insulator inside the white, but I can't remember. In this case, the OP will need to cap off the white or Blue/white wire for 120 volts usage anyway .
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