[Hallicrafters] SX-101 Mark 3

[MIKE SOUHRADA]

Brad Hyde
> I have been trouble shooting an SX-101 Mark 3.
Don't have data on the M3 so looking at 101 Mk 1A
schematics and data. You might be spinning your wheels with
an erroneous assumption.
So here's my thoughts.

The BFO is not working.
That tube 6SC7 as I recall can be nasty to work with. Did you test it
first?
>I started checking voltages on the tubes and found that they were much higher.
How much in %? What are the BFO readings.
Know what you mean having trouble with a GPR 90 now. The 101 voltage 
spec is 117 so it shouldn't be too far off. I'm currently running 
118-122 VAC here and had lots of trouble with a KWM 2 but those are 
rated for `110 VAC.
When I tracked the actual voltage back it calculated exactly to the 
difference in line voltage standard change.


I remembered having this trouble with a Collins receiver one time and the
problem was with the filter choke. FOR THE COLLINS

Sure enough the resistance on the choke was 16 ohms instead of the 310 
ohms expected.
FYI The choke specified in mine is 9Hy 135 Ma 250 ohms DC. It seems to 
me that ripple would be very bad but still not cause the BFO to NOT 
WORK? So I'd look for something else first; then solve the ripple problem.
Make sense?

Does anyone know where I can either get this choke rewound,  or get a 
new or used one?
I need a 8 Henry choke rated at 85 milliamps with a winding resistance 
of about 310 ohms.
You might consider a rewind. Shouldn't be that hard but bet someone has 
one near your
need. What are the bolt hole dimensions?
Mike Iowa