Thanks a lot of this.
I just managed to get a 8568B that attenuator has some problems with the 20dB step.
These instructions encourage me to open the attenuator and clean the pads with isopropyl alcohol. Now it works fine.
I didn't made a testped for it i just cold moved carefully the solenoids and checked with dg8saq vnwa the attenuator pads. I'm not sure is the solenoid stuck or is it actually a contact failure.
The instructions how to disaasemble the attenuator was very accurate and easy to follow.
BR, Jarmo
