Always worth taking it apart and attempting the repair on your own. Many people (myself included) have had good luck repairing these even outside of o-ring issues (for instance I¡¯ve found a little oxidation on the switch contacts that prevent the plunger from moving through the solenoid).
When you say that on one pad the attenuator can switch but the coil still draws current, are you sure that¡¯s right? That seems strange to me.
Feel free to post follow up questions when you pull it apart. But the operation is relatively straight-forward and they¡¯re easy to operate on the bench with a current-limited power supply.
Anyway, it¡¯s worth figuring out what¡¯s wrong before you condemn it as irreparable or send it off to someone else to repair who would probably use the same troubleshooting and repair techniques that you would.
Matt
Hi Folks,
Looks like the step attenuator (5086-7814) in my 8566B is busted.
I took it out, and measured it on the bench. The 10dB stage I can switch on and off correctly, although in one of the states it keeps drawing current. The attenuation latches fine, but it doesn't open the circuit to the coil.
None of the 3 20dB stages seem to do anything except draw around 70mA. 2 of them are stuck on, 1 off (40dB total attn).
I read here about the plunger o-ring issues, so I was planning to take it apart.
My questions is what's the best course of action here? Take it apart, try to get another one on ebay (~$150?), try to get it repaired?
In the 40dB and 50dB states that I can select the response is flat and matching is good from both sides.
Thanks!
