Tektronix TDS784D

[tektronixman]

Well here we go again another faulty one. This one has the usual acquisition failure on start up but the fault is strange. Ch2 seems not to be working at all just noise until I select a timebase of 12.5 or 25ns . The signal path test takes about 20mins to run and ends with faults All the four traces are vertically misplaced from there associated curser numbers  Has anybody seen this before and any suggestions of where to start looking