I am observing an odd failure with my Tek TDS 640A.
It is hanging up during the routine power on diagnostics but only when it's fully inside the case. When out of the case or only 3/4 of the way it functions normally but fully inserted it consistently freezes during the power on diagnostics.
I have verified there is no internal component being grounded to the case.
When in failure mode DS1 flashes ".P" then ".8" then ".3" (this failure code is not in the troubleshooting tree)
A15 attenuator board was recently replaced but is not believed to be related.
I can't recall seeing an instrument fail only when fully shielded inside the case. I've checked the ground on my station.
Has anyone seen a similar failure?