Lecroy9400 Trouble with one channel

Hello,

yesterday I got my used Lecroy9400 scope. Unfortunately the second channel is
broken.
A signal in the second channl eg. a sine wave looks like as if there where
only two or three quantization steps.

When I turn up the signals offset, the signal becomes clearly and continious
in the upper quarter of the screen.
On the rest of the screen the signal loks as mentioned above.

Inmy opinion there might be something wrong with the ADC.
Does anybody have an idea or maybe a service manual.
Is it possible to perform a selftest?
??

Thanks

fabmo

 

What a coincidence!

I just started working on a Lecroy 9410 with a blank display.

All the voltages to the CRT are present but no display.

If someone has the service manual please let us know!

JAM

 

What a coincidence!

If you working on your scope and you find the ADCs please let me know which
kind they are.
I think I woult change them by suspiction.