Fender Stage100 combo, reverb problem, can someone please help ?

[bluellew]

Greetings, i'm new to the forum and very grateful for the opportunity to learn. I bought a Fender stage 100 combo in a pawnshop a week ago and forgot to test the reverb until i got home. I get no signal feed through the reverb and turning it up on either channel only produces an increasing hum.
After searching the web, i came upon this great site and followed the older posts relating to similar problems. Tried all the things that are mentioned in the older posts. At this point i have replaced the 4560 chip to no avail. With the drive and recovery rca's disconnected on the board, the hum is the same as with the tank connected. i connected the red ( drive ) rca to a speaker to see if there is a send signal and i get a faint guitar sound off that line. It would seem that there is a problem with the recovery side of the system. I am not an electronics expert, but i have done a fair amount of repairs to systems when i have understood what i was dealing with. ( i am able to do hardware repairs to cellphones )
If someone would be so kind as to guide me through a troubleshooting to a repair, i would be very grateful.

[52 Bill]

Welcome to the place. You didn't mention if you tested the reverb tank itself. Take an ohm reading across the RCA jacks to see that you have continuity through the transducer coils.

[Jazz P Bass]

Have you checked the resistance of the input & output coils of the pan?

And check the wires themselves.

[bluellew]

Thanks very much for the response. Forgive my delayed response, i was expecting an email to inform me of activity on the thread. Anyway, i pulled the tank out and measured the coils. The input coil measures 60 ohms and the output coil zero. I guess that's the problem ? Is it possible to repair a dodgy coil ? how does a coil like that fail anyway ?

[bluellew]

Update. I swallowed my terror and pulled out the soldering iron and magnifier and re soldered the teeny little wires to the coil. Now the readings on the coils are 60 ohm on the input and 215 ohm on the output. I am now going to do a test and hopefully i'll be able to re assemble this fabulous little solid state amp. Thanks guys. If it works out fine i'll let you know. If not, i guess i'll be back with some more questions.

[Jazz P Bass]

Good job with the magnifier.

The coil wires get beaten up pretty good from 'overexcusrsions' of the tank.

60 & 215 ohms sounds like you have a working tank now.

[bluellew]

Thank you guys, very much, for pointing me back to the tank. One sometimes rushes the first steps instead of making sure. I thought that i had checked the tank, but i hadn't done it thoroughly. I have managed to sort out my problem and i am now a happy chappie. Regards.