HP 8566B spectrum analyzer trace flicker/glitching

[tonycox01]

Hi,

I recently got hold of an HP 8566B SA which largely seems to be working OK apart from a random flicker/glitching of the trace display. The trace appears to break down in to a flurry of horizontal lines at random intervals and positions. I've trawled for similar issues with the 8556B but not come across anything so I thought I would ask a question here before diving in to serious troubleshooting - just in case anybody has seen a similar problem or has any suggestions about where to focus my troubleshooting efforts.

I have created a short video that demonstrates the issue (this brief capture was from the self calibration routine).

https://youtu.be/LvoDBJFQfnM

thanks in advance for you help/suggestions.

Tony

[jfphp]

I will try with the power supplies (ripple) mainly those going to the display board.

[tagchen]

in this old measurement tools check power supply caps, mostly higher voltage (400-450V) are the problem.
this problem can be keramic caps for digital chips (cpu boards or so)

have you picture from inside?

installing retrofit document can little help.
 08566-90151-retrofit.pdf (4410.18 kB - downloaded 99 times.)

service and repair manual to big to post, find in keysight page
Part Number: 08566-90042 (Dec84). This manual is provided for information only. The 8566B and 8568B are no longer sold by Keysight. Note: the file size is 36.37 MB.

[tonycox01]

Thanks - no picture yet but I'll try and get some.

I'll start with the caps on the power supplies and see where that goes.

cheers

Tony

[Johnny10]

I might check for input power line noise.