Hi Peter,
> The relay may be sticking because of residual magnetism.
This is an interesting idea. I was wondering about something like that.
But the relay does kick off fine, if I totally shut off power to the amp.
It's wired for 220v. -13v is created and used for the relay, thru some
resistor, diode.
This is also used in the grid circuit.
If it was residual magnetism, I would think it would not be affected by
turning off the main power?
I'm stuck on thinking that the problem with (apparently) no cutoff, and this
sticky
T/R relay, are related, since they share some circuit pieces. (relay coil
and grid circuit)
I've seen some posts talk about the caps in the grid circuit being blown out.
(C201/C202)
I'm going to test those caps too. Maybe I have a short in one of the caps.
Since they're on the other side of 33 ohm resistors (R201/R202), that could
give me
my weak resistive short to ground that the relay coil would see? (would the
tubes work right then? they seem too, other than no cutoff)
schematics are here for the truly curious
ftp://bama.edebris.com/bama/yaesu/2100b/b-sch1.gif
ftp://bama.edebris.com/bama/yaesu/2100b/b-sch2.gif
-kevin
Peter SM/G3RZP wrote:
> The relay may be sticking because of residual magnetism.
> A piece of paper between the relay poles, i.e the coil centre and the
> armature,
> will prove this - if it's residual magnetism, the relay will drop out fine
> once you increase the magnetic reluctance. If that's the case, a bit of
> Scotch
> or even PVC tape should provide a cure. Reversing the leads to the relay will
> also help for a time, although if there's a diode across the relay coil,
> that will need reversing too.
>
> Some relays provide a copper stud to keep a small air gap: others even have
> an adjustment screw for the same purpose.
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