Hi. I have a studer A80 that cannt record. ( both channals) Its a 1/4" sterio mashine. (ozilator board has 2 relays). Erase and playback is ok. Signal through record amps is ok. record button lights up. heads are clean. power suply to audio boards is ok. I have the service manual. Does some one know this mashine? Thanks in advance. Bjorn.