Elka Panther 300 hum

[rich]

Does anyone know what might be causing a hum in the bass section of my Panther 300? It gets louder when you turn up the bass volume and it is absent when the volume is down all the way or unplug the cable that works the bass, I checked the cables, connections and they seem fine. I did notice a little bit of hum through the other keys when you play a key with the bass off.

[karl]

Hi Rich,
No, Sorry I do not have a Panther. I looked around for a schematic but no dice. Maybe someone here can help with this ?

Most likely there is a ground connection loose on the inside.
Follow the wires from the bass keys to a circuit board and
carefully check for a loose or broken wire. If that does not fix it, look on the circuit board for loose components. Probably a capacitor. If none of these are found there is a good chance
the power supply caps are going. ( this could also explain the decay bulb blowing, due to high ripple on the power supply rails)
An easy way to check this is to get a new cap of the same capacitance and VOLTAGE value and use jumper wires to connect it ACROSS a capacitor in the power supply. Make sure you connect + to + and - to -. And turn off when hooking it up. Try each cap in the power supp;y. If the hum goes away replace that cap.
Please respond with any questions
Good Luck

- Karl

[rich]

Thanks Karl, we got it, 2 bad caps in the power supply, working fine now,
Rich.