Hi all,
I have a Tektronix TDS 694C with noisy input channels.
The examples below are with nothing connected to the inputs.
In 5 GS/s / 10ns/div mode, there is some 25 ns / 40 MHz cycles showing.
In 10 GS/s mode, it shows as some 5 GHz noise.
The input channel scaling does not seem to matter, the noise is pretty constant in amplitude on screen independent of voltage range.
Has anyone else seen this?
Could there be a problem with some power feed, or something?
The triggering only works on channel 1 & 2 on this scope. I have not yet tried moving the trigger chips around. Could those have anything to do with it?
Thanks for any hints, help and/or information!
Also, any pointers to repair information for this scope, and/or firmware never than v6.4e, would be much appreciated!
Best regards,
Ragnar