LeCroy WaveSurfer 10

[Teichhermelin]

Can you find the error yourself? Or is this just a service at Lecroy?
The 4th channel no longer displays the calibration signal correctly.

[shakalnokturn]

There's apparently a small value of capacitive coupling letting the fast transitions appear.
Estimating the capacitance may give you a few hints for troubleshooting.

It could be a broken connection at the BNC, defective relay, or fault somewhere in the low frequency path in the front-end.

Even without schematic comparative probing  should get you to the problem easily, the main issue is how to run it disassembled while keeping things cool.

[boB]

Have you tried swapping probes on channel 4 ?

[Teichhermelin]

I did that.

[Teichhermelin]

When I have a lot of time I'll take a look at it! First of all, thank you for the information!