EMT 140 repair?

[theposterkid]

Has anyone ever worked on an EMT 140?

Output #1 is not working on ours, and I've tried swapping out all 3 of the tubes from one channel to the other, but with no luck. The tubes seem fine as nothing seems to change.

I wanted to open the thing up to see if the connection on the pickup has come loose somehow, but I was worried about the thing falling apart on me as I have never worked on one of these before. If I take the big wooden exterior wall off on either side, the plate itself is not going to be affected, right?

[sonicmook56]

The plate is suspended in a steel frame with wood sides bolted onto the frame, so It's safe to take the sides off. If your looking at the front (where the I/O is) you want to take off the left side to access the driver/puckup.

To trouble shoot, I would swap the inputs (they are on long connector ones) to the amp to see if the fault is the pickup or the amplifier.


This is what the right side looks like inside with the motor and dampining assembly.

[djimbe]

How'd you swap tubes around without removing the case side? Pull the amps? Opening the case is much easier and will NOT hurt your 140. These things are extremely well built and the amps are a pleasure to work on. So well layed out, labled, and constructed. Them crazy persnickety Germans...

I'd first look at the coax cable that hooks the accelerometer (the "pickup") to the amp and make sure that's tight and ground isn't frayed. This is what sonicmook is talking about. I'd also check continuity at the amp I/O connector and the tagboard (if yours has one) where most of the wiring is landed. I worked on a 140 last year that had some odd stuff going on in that area. It had been sitting unused for at least 10 years though.

I have docs for the V54 and V54ST amps, so PM if you need 'em...