Just picked up another Hohner electric piano, this time the Cembalet CF:
http://hohner-cembalet.com/hohner_cembalet/Cembalet_CF.html
It powers up and does nothing but hum - no keyboard signal. Replaced the e-caps and resistors, same deal. The original volume pot had been removed and jumped together. Installing a replacement 250K pot did not make a difference, and does not affect the hum level when turned.
The vibrato bulb is burned out. I have a Cembalet N which does not have a working vibrato bulb, this does not stop the keyboard from working, it just means that I don't have a vibrato option, so I am assuming this one must work the same.
There is no voltage at the pickup. The other Hohner EPs typically have 150-200vdc at the pickup. This one also shows continuity between the pickup and the reeds. Even with the preamp unhooked from the pickup and reeds, their hookups on the board still show continuity, so it's not anything with the harp itself. None of the other Hohners behave this way, if they pickup and reeds have continuity, they are shorted and there is no sound. But this model has a strange coil thing in parallel with the reeds and pickup, which if I'm understanding the schematic correctly, would explain the continuity.
What's the next thing I should look at here? The transistors seem to have appropriate voltage readings. Thanks!
http://hohner-cembalet.com/hohner_cembalet/Cembalet_CF.html
It powers up and does nothing but hum - no keyboard signal. Replaced the e-caps and resistors, same deal. The original volume pot had been removed and jumped together. Installing a replacement 250K pot did not make a difference, and does not affect the hum level when turned.
The vibrato bulb is burned out. I have a Cembalet N which does not have a working vibrato bulb, this does not stop the keyboard from working, it just means that I don't have a vibrato option, so I am assuming this one must work the same.
There is no voltage at the pickup. The other Hohner EPs typically have 150-200vdc at the pickup. This one also shows continuity between the pickup and the reeds. Even with the preamp unhooked from the pickup and reeds, their hookups on the board still show continuity, so it's not anything with the harp itself. None of the other Hohners behave this way, if they pickup and reeds have continuity, they are shorted and there is no sound. But this model has a strange coil thing in parallel with the reeds and pickup, which if I'm understanding the schematic correctly, would explain the continuity.
What's the next thing I should look at here? The transistors seem to have appropriate voltage readings. Thanks!