Polar EM 92 won't Calibrate

Please help. I have a Polar EM 92. It was working great but all of a sudden the back gauge came all the way forward. If we put a new measurement in it would go back but then again all the way foraward. I shut the machine off thinking it was just a calibration issue but when I turned back on the machine and pushed the handle to Calibrate it just went all the way back and stopped. All that is on the screen is a zero. I checked the battery and it has power, all the fuses seem good. Any help as to what is causing this is highly appreciated.
Thank you - Hank

 

Hi sir:

Please test:

1) Keyboard power supply Display: +9Vdc if you are measuring for example:9.3 Vdc is faulty power supply
repair or replace.

2) measure the Power supply Keyboard BR:+5vDC again if you measure 5.3 Vdc is faulty the power supply repair or replace

3) If everything is o.k in the points 1+2 go the electronib board TAM: look for LED's ; a) LED V1 ON or OFF - flashing when moving backagauge b)LED V2 On or OFF Counting forward. c) LED V3 ;OFF will lit up by o.5 seg when passing Reference point.