Silverface Fender Twin schematic

[plookit]

Could someone help me identify the year and schematic number of this Silverface Twin. The owner wants a mod to be reversed.

Thanks

[Ten Over]

Serial number indicates 1980 which would make it a 135W model. Picture of the rear and/or picture of the guts would verify.

Fender Twin 135 Schematic.png

Fender Twin 135 Layout.png

[Ten Over]

If this is the export model...

Twin Reverb 135W UL Export PNG.png

[plookit]

This is fantastic. Thanks so much. I’ll get a picture of the back. I don’t have it in my bench yet, the guy wants me to put the hum pot back in. He says it was modded out of it some time ago.

[plookit]

So, the task is to put back a hum pot that was removed. The amp sounds great except when the reverb is engaged and then it has a lot of hum. Any thoughts on what that might be. It’s been sitting unused for a good while.

[sluckey]

So, the task is to put back a hum pot that was removed. The amp sounds great except when the reverb is engaged and then it has a lot of hum. Any thoughts on what that might be. It’s been sitting unused for a good while.

Hum pot most likely will not fix that. Does the reverb hum if the footswitch is disconnected?

[plookit]

No, hum goes when you disengage reverb

[sluckey]

No, hum goes when you disengage reverb

Guess I need to be more specific. Unplug the two RCA phono plugs from the RCA phono jacks on the back of the amp. Turn the reverb pot up. Does the amp hum?

[plookit]

Ah. I’ll try that tomorrow. Thank you.

[Ten Over]

So, the task is to put back a hum pot that was removed. The amp sounds great except when the reverb is engaged and then it has a lot of hum. Any thoughts on what that might be. It’s been sitting unused for a good while.

Yeah, it's an export 135W. sluckey's got you covered on the reverb hum.

[plookit]

When I pull out these two plugs (one from the foot switch and one from reverb tank) the hum goes. It also goes when all are plugged in and the switch is turned off