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Hi all,
Another plea for help! I have replaced relay K1
with a 2.5K solenoid as per the updated T4XC circuit, as I discovered the old
relay (old 15k solenoid version) to be open circuit. Of course I also added
the necessary 1.5K resistor in series. All as per advice from Garey - K4OAH (for which many thanks
Garey).
Now, when I go into tune mode, the relay will not
pull in. There is only 30V across the solenoid, and should be nearer 40V I
believe from my calculation (assuming plate resistance = 11.5K). I suspect
the VOX control tube is not conducting fully. Voltages (in Tune mode) on V10 are
as follows:
Pin 6 plate: 215v (manual
says 170v)
Pin 7 grid: -2mV (manual says
-100mV)
Pin8 cathode: +880mV (manual says
-660mV)
R70 measures spot on 82ohm
Have checked all outputs on AC4 and these all seem
to measure fine.
Any thoughts on where to look for likely problem?
Could diodes CR13 or CR14 have blown and if so, what would be effect? Could
anything have been taken out when the solenoid blew (can't see anything
vulnerable) or could the solenoid originally have blown due to failure of other
components in this area?
Hoping someone might give some
pointers!
73 to all
David
G4GTP
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