Hp182T with 8559A spectrum Analyzer

[realfran]

Hello, some help please the 182T display unity after 25/30 minutes work and after the luminosity starts fading until trace disappear, pushing find beam work.
I need to switch off for some time and switch on start working again, please some help to figure out the faulty.

[George Edmonds]

Hi

It is the high value resistors for the CRT supplies that are changing in value due to the applied voltage.

A very common problem

G Edmonds

[realfran]

If I push the "FIND BEAM" I get the beam, if I put the rear OUT D connected to the front" EXT INPUT BNC" pushing " EXT DISPLAY" I get the SA trace.