Gould Oscilloscope OS1200 Sweep compression

(Sorry forgot the link to photos on previous message)

I have just recently aquired a Gould OS1200 oscilloscope.

Basically it works fine except that the Sweep trace compresses up on the right hand side of the when I set the timebase to 5uS and up.

I have measured most test points on the Horizontal timebase PCB and cannot find anything unusual.

Please the following example pictures showing the compresses trace. Also have photos showing the Sawtooth ramp generator and ramp output if this helps.

I am really looking for some guidance on where I should be checking.

Regards Ivan

check/replace the X plate driver trannies, one is probably wonky

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

on

Have checked them and they seem OK allthough the voltage on the plates are a bit low. I have had sugestions that the problem may lay in the timing of the Hold off/blanking circuit.

Regards Ivan