I have a Piranha shear (date of mfg 1999) with a servo back gauge.

The back gauge controller does not function correctly. Is this a common failure?

Symptoms:

On power up the controller acts normal and prompts for calibration, displays "CAL".

The keypad button "CAL" gets no response. The "6" key will send the back gauge home. The calibration routine completes and the display correctly shows "0.250".

And that's it... no response from the keypad. A certain (random) key combination will get the back gauge to move, usually to the clearance position. The positional display reads the correct position of the back gauge. Once at the new position additional key presses result in random characters on the display and no predictable motion.

The servo amp, encoder and display / readout appear fully functional. DC power supply (12V) is stable at 11.55vdc.

Steps taken so far, as suggest by tech support. Replace the $1000 dollar encoder and the $1000 keypad with no improvement.

I think the controller board is a custom for Piranha, please correct me if I am wrong. It has a Z-1 micro controller daughter board.

Suggestions of things I should try or parts / repair sources would be welcome.


Thanks in advance for the help.