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Hi to all you kind and helpful people. About a month ago i successfully repaired my reverb tank with help from the forum. Something has gone awry again and i am not sure where to start.
Everything was fine until i plugged a rack-mount effects unit into into the loop. I wasn't expecting a problem and thus i cannot say at which moment the hum first showed, but i am certain it was moments after i plugged the jacks into the loop.
Since the hum sounded similar to the time before, i thought that perhaps my soldering had failed and i immediately pulled out the tank and tested the transducers. It seems there is no problem on the tank. I get 200 odd ohms on the one and 50 something on the other side.
Exasperated, i plugged the rca's into the tank while it was outside the cab to try and find the fault. The hum was gone ? Tapping the tank while it was out of the cab, i could clearly hear the springs vibrate. As i moved the tank to the cab and put it into place to screw it down, the hum suddenly increased. It seems the speaker's magnet affects the tank ?
It seems that when the effects unit is in the loop, the reverb is disconnected. When the effects unit is disconnected, the hum exists. As you increase the level, the hum increases.
I am loath to jump at removing the board again until i have a protocol for tracing the fault, since the knobs on the pots are fairly tight and the last time i removed them, i had to rebuild one of the pots because i had managed to pull the shaft inside the pot and the pot was dysfunctional. I successfully repaired the pot, but it was a very time consuming and hairy process.
I am hoping that my description of the problem will enable someone to assist.
Everything was fine until i plugged a rack-mount effects unit into into the loop. I wasn't expecting a problem and thus i cannot say at which moment the hum first showed, but i am certain it was moments after i plugged the jacks into the loop.
Since the hum sounded similar to the time before, i thought that perhaps my soldering had failed and i immediately pulled out the tank and tested the transducers. It seems there is no problem on the tank. I get 200 odd ohms on the one and 50 something on the other side.
Exasperated, i plugged the rca's into the tank while it was outside the cab to try and find the fault. The hum was gone ? Tapping the tank while it was out of the cab, i could clearly hear the springs vibrate. As i moved the tank to the cab and put it into place to screw it down, the hum suddenly increased. It seems the speaker's magnet affects the tank ?
It seems that when the effects unit is in the loop, the reverb is disconnected. When the effects unit is disconnected, the hum exists. As you increase the level, the hum increases.
I am loath to jump at removing the board again until i have a protocol for tracing the fault, since the knobs on the pots are fairly tight and the last time i removed them, i had to rebuild one of the pots because i had managed to pull the shaft inside the pot and the pot was dysfunctional. I successfully repaired the pot, but it was a very time consuming and hairy process.
I am hoping that my description of the problem will enable someone to assist.
I did consider jumping it a while ago, but had no idea if it would make matters worse. It seems as if some sort of reset has occurred, because the simple act of bridging the inputs has returned everything to normal. I guess the effects unit is dodgy. I am sooo grateful to you for saving me from having to open the amp again, i was really dreading having it in pieces on my bench again.
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