Loud static from my Wurlitzer 200a

[Rey]

Hello! I am new to this site; so, I'd like to extend a warm introduction to you all. I've noticed that these forum sites offer the very best knowledge from experienced technicians, and I'm hoping someone can offer a bit of assistance. While playing my wurly at rehearsal the other day, it suddenly began a very loud static/crackling sound. When consulting the service manual, this issue was split into two categories: Hiss and Noise (can control with volume) and Hiss and Noise (cannot control with volume). What's tricky about this is the noise is slightly controlled by the volume, but I can't tell for certain. It's seriously painful to see (and hear) my baby in this condition. I am new to electronics repairs, and I'm hoping that someone out there has some insight for me. Thanks!

[Jazz P Bass]

Wurlitzer 200 schematic

Here is a link to the schematic.
Link:AnalogRules / BASE - Wurlitzer 200 Schematic

[Rey]

Thanks for the link. I have managed to procure the schematics and other diagrams from the service manual. I guess what I'm asking for is advice from experience. I'm on a time limit, and an intuitive point in the right direction would save me much unnecessary time. Any suggestions are welcome.

[Enzo]

OH I hate these things...

There is a long metal "comb" along the length. Each key strikes a short metal tine. The tines vibrate between the teeth of the comb. Ther comb has voltage on it. Make sure there is no debris on the comb and tines causing intermitant shorting.

Make sure the mounting hardware is all snug.

Ball up your fist and whack the end of the instrument. Does that cause any noises? Looking for loose connections or hardware.

[kdawg]

If you take off the cover and then the shield, you can usually tap down on each of the wooden dampers - work your way from one end to the other while you have the unit on, volume up just a bit. You should eventually find the crackling tine that is contacting the sides if that's the problem. You'll have to loosen the screw and move it around, but that changes the tuning too - read the service manual on the tuning part.

Also would be a good time to see if the power caps and other electrolytics have been replaced. Check if the noise comes out of both the aux jack and the speakers also if it's not a tine issue.. could be a power transistor issue.

-kdawg