EMT 240 reverb dumping failure

[gaetanopellino]

Hello. Few days ago I got the bad surprize that the reverb time control of my belowed EMT 240 Gold Foil only increases and did not decrease the reverberation time lenght. The result is that now the reverb time is stuck in 5 sec long reverb. There is no direct access the the motor controlling the dump plate. I don’t use remote control but even with it, the problem is the same, so it’s not question of switches. I’ve looked for specific informations or similar cases all over the web but ain’t been lucky. Please help!

 

[guy_4]

Hello,

Did you fix your 240 issue since April ?
If not, have you tested if the switch " Down " is making,g a good contact ?
You can easily by-pass it with a wire to test.

Best,
Guy

 

[gaetanopellino]

Hello,

Did you fix your 240 issue since April ?
If not, have you tested if the switch " Down " is making,g a good contact ?
You can easily by-pass it with a wire to test.

Best,
Guy

Fixed! Thank you.

 

[Brian Roth]

Fixed! Thank you.

For my future reference, what was the cause and required repair? Thanks.

Bri

 

[gaetanopellino]

Issue fixed! In the pcb card located on the bottom of the unit there are two power transistors, BD135 and BD136. Their purpose is to provide the necessary voltage to drive the two motors that move the dump plate. One of the two was defective. When I disconnected the motor the transistor provided the correct 24v but when I reconnected the motor the voltage output was only 5v. I replaced the two transistors and now the unit works perfect.

 

[musipol]

I like those DIY looking heatsinks. Looks like something I would make for something that’s not dissipating that much power.