[sdiy] what are these?

[harrybissell]

Older Fender amps used a Neon/Photocell for tremolo....

(not that I have one, but I did repair one of those in 1968  :^|)

H^) harry

"Roy J. Tellason" wrote:

> On Saturday 23 October 2004 05:37 pm, Roy J. Tellason wrote:
> > I'm still sorting through parts...
> >
> > In this small bag labeled "optoisolators" I find these five things.  About
> > an inch long more or less,  mayba a cm wide,  and irregular in contour --
> > there are two wires coming out of each end,  and the rest is covered by a
> > layer of heatshrink.  Markings are "SIGMA 932" and "301T1-PC" and "26148".
> > I'm not measuring anything with an ohmmeter between pairs of wires...
> >
> > Reminds me a little bit of those units that Fender used to use for
> > "vibrato" except that these were obviously mounted on some board or other,
> > wires are fairly short and all pointed in the same direction.
> >
> > Any of you guys have any ideas about these?
>
> Ok,  I opened one up,  since there only seemed to be 3 rather than 4 leads
> coming out of it.  And what do I find?  Another layer of heatshrink,  this
> one thin and yellow.  I can see what looks like the tip of a neon bulb
> peeking out of one end of the shrink,  and this yellow stuff is apparently
> transmissive enough that this time when I put the meter across the photocell
> I get readings that drop down to close to 100 ohms as I get closer to the
> lamp over my desk.
>
> Regular optos I can find a use for (and I have some,  and plans for them),
> but not ones driven by a neon bulb.  Any of you guys have a use for these?