开云体育

I have a problem with this unit. I have not used it for some time now but it was working fin then. But now when I switch the unit. the trace is not good and has large parts in it where it win not on the screen at all When I look at the R channel that's the same as the A/R channel.It looks like big steppes on the trace and these steps get longer as it sweeps fro 300KHz to 3GHz.

I have not seen anything like this fault.

Can anyone give me a clue ?

I have measured the supply rails and they seem to be fine and stable.