Lexicon 200, noisy baby

[psych60s]

Hello everyone

Just noticed that my Lexicon Model 200 outputs a kind of cyclic-modulated floor noise on the left channel.

The meters don't read anything, and the noise stops when I mute the input ("INPUT MUTE" pushbutton or "INPUT LEVEL" slider all the way down).

Any idea before I open the unit?

Thank you!

 

[jensenmann]

There´s a load of tantalum caps inside which should be replaced before the unit fails due to a dead one. Recapping in general is a very good idea. If you have done that and it still is noisy then check the regulators. All that doesn´t adress you problem directly but will make your 200 longtime-proof, anyway.
The battery in most cases needs to be renewed, too.

 

[psych60s]

My 200 works quite well, and I go no error code so I've assumed the PSU and supplies right voltages.

Attached is the input section, juste before the input level control, and I strongly suspect that's where the trouble is located. Seems that the input mode switches are very dirty. These old Schadow switches...

I'll trace it with a scope to be sure.

 

[pvision]

The 200 is a different generation, so likely uses very different parts, but the LXP range and some of the MPX range are suffering badly from noisy input / output / mix pots and bad encoders

Nick Froome