K
Ken Grant
Hello all,
I'm refurbishing an HP 8640B generator. I eventually lose output and
I've traced the problem to the slider switches on the filter board,
A10A1. They've all been disassembled and cleaned. The contacts
affected seem to be to the left of the aluminum slider clamp. Light
finger pressure will sometimes bring things back to life.
The finger contacts all appear to be in good condition and not
mis-shapened.
There are two very thin shim washers between the slider clamp and
each clamp support. Proper operation seems to depend upon the
tightness of the clamp screws. Is there a proper procedure for setting
up this section? The service manual doesn't mention anything. Thanks
for any help.
While I'm at it, I've had success with repairing a cracked delrin
gear. Having removed the gear, put it in a refrigerator's freezer
compartment for a few hours. This is an effort to cause the delrin to
shrink more than the brass hub. Drift out the brass hub. Mine came out
with just a gentle tap on a hammer and drift.(Credit the next part to
Jeff Liebermann). Use 24 hr epoxy to glue the Delrin back together.
Use a round file to open up the delrin centre hole so that the brass
hub will just fit back in. Epoxy the hub back in.
One poster has suggested soaking nylon / delrin in warm water
overnight will restore some of it's pliability. I did this to all of
the delrin gears. Don't know if they're more pliable, but they're sure
nice and clean!
Ken
I'm refurbishing an HP 8640B generator. I eventually lose output and
I've traced the problem to the slider switches on the filter board,
A10A1. They've all been disassembled and cleaned. The contacts
affected seem to be to the left of the aluminum slider clamp. Light
finger pressure will sometimes bring things back to life.
The finger contacts all appear to be in good condition and not
mis-shapened.
There are two very thin shim washers between the slider clamp and
each clamp support. Proper operation seems to depend upon the
tightness of the clamp screws. Is there a proper procedure for setting
up this section? The service manual doesn't mention anything. Thanks
for any help.
While I'm at it, I've had success with repairing a cracked delrin
gear. Having removed the gear, put it in a refrigerator's freezer
compartment for a few hours. This is an effort to cause the delrin to
shrink more than the brass hub. Drift out the brass hub. Mine came out
with just a gentle tap on a hammer and drift.(Credit the next part to
Jeff Liebermann). Use 24 hr epoxy to glue the Delrin back together.
Use a round file to open up the delrin centre hole so that the brass
hub will just fit back in. Epoxy the hub back in.
One poster has suggested soaking nylon / delrin in warm water
overnight will restore some of it's pliability. I did this to all of
the delrin gears. Don't know if they're more pliable, but they're sure
nice and clean!
Ken
