That's great - seems like it should work OK. I should have clarified that any wirewound pot will have lots of inductance - even a one-turn type, which would have a toroidal element. The multi-turn ones actually have helical elements, with as many loops as there are turns of shaft rotation - and even more inductance.
Ed
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--- In TekScopes@..., "Bruce Lane" <kyrrin@...> wrote:
Hi, Ed,
Thanks. I just checked the schematic, and it looks like the pot in question does nothing more than set DC bias level on the emitter side of an NPN transistor, configured in common-base.
Time to investigate multi-turn pots...
* REPLY SEPARATOR *
On 26-Jan-12 at 04:05 Ed Breya wrote:
If the pot has to vary a fast risetime or wide bandwidth signal, a
ten-turn style will likely not work. Those are built with many turns of
manganin wire wrapped around a linear mandrel, then rolled into a toroidal
resistance element - it will have a lot of inductance.
If the pot just needs to set a DC bias or control a low frequency signal,
no problem.
Old pots of any style can sometimes be worked around enough to clean up
the wiper contact degraded from years of idleness or bad storage
environment - but it can take a lot - maybe maybe hundreds of full
rotations. It may be worth trying that first.
Ed
--- In TekScopes@..., "Bruce Lane" <kyrrin@> wrote:
Fellow Tekkies,
I got my PG508 in and, with a bit of cleaning of the controls, found it
to be nearly pristine and very functional indeed.
There is one issue: I'm finding the variable control on pulse duration
does not give me precise enough control, and (like most older pots) tends
to jump a bit.
My gut reaction to curing this is to try interfacing a 10 or 20-turn pot
to it, preferably through a blank plug-in so I don't have to deface the
front panel.
Thoughts on this idea, and how to best accomplish it, would be welcome.
Thanks much.
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies ()
Assoc. member, AZA & AAZK for many moons.
"Salvadore Dali's computer has surreal ports..."
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Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies --
kyrrin (at) bluefeathertech do/t c=o=m
"Quid Malmborg in Plano..."
