Bill writes...
>
>Both units are out on the bench. Worked them both over the entire range.
>Nada :{
>
>BK
Doesn't sound good. :-(
It's been several years since I've had the Spit sender out on the
bench and I can't even remember much about the physical construction.
As you probably know, it's typically nothing more than a wiper arm
moving across some coiled resistance wire. I know of only two failure
modes.
In one case the wiper or the coil simply wears out...sometimes
breaking the coiled wire. In this case I'd say the unit is toast.
The other failure mode is a bit more insidious. Often the
construction calls for "riveting" together all the bits that need to
pass current. Over time these connections can oxidize and fail.
I'm not sure it's practical to drill out the rivets but I seem to
recall doing something along the lines of sweating these joints with
solder to bypass the mechanical connection.
Of course, they need to be bright and clean enough to accept the
solder in the first place.
Cheers!
Tom O'Malley in Southbridge Massachusetts
'74, '77 Spits
|