SO the other day I decided to have another crack at the Otari MX-5050 QXHD. I discovered that the head stack comes off as a single unit, so I removed it and clened the contacts on the socket connector. Success! All tracks record and play, tho the deck is badly in need of calibration. Fortunately my radio station buddy emailed me and is bringing me two standard test tapes - one for 7 1/2 and 1 for 15 ips. Funny thing about this unit is ALL the adjustments are in the preamp section - including bias etc. Luckily the heads appear to be in excellent shape, so I am hoping to be able to get this unit working near 100% soon.