Last night I moved my 8640A to it's new rack and gave all the knobs a tentative twist because it hadn't been used in a while and wanted to make sure all was well before I tied it down.
All was well until the last bit of turn on the output attenuator... it suddenly stopped making those satisfying dedent clunks; instead I could hear the whisper of rotary switch contacts. Oh-oh!
Inside, there are 5 large black plastic cams and a "gear" that provides the dedent stops. One of the cams and the gear split. Some of the other cams have growing cracks, and they all have rows of what looks like tiny bubbles- kin of like tree rings.
I searched the archives, but everything seems to point to fixing the other 8640 gears or the electrical part of the attenuator. Anybody ever fixed on of these?
It doesn't appear to be an easy fix. I could epoxy them back together, but I know other sections/areas will eventually fail. I don't feel like molding 6 different shapes either...
-Dave
