Just recently got a Yaesu ft-101e that needed some alignment and the only
thing I cant seem to get "accurate" is the neutralization, the best I can do
is to rotate the adjustable plate capacitor till I get the lowest output
reading on the power meter, which range from 50 to 80 watts depending on the
band and it seems to put out a clean signal this way.
Trying to get a higher output reading by adjusting the capacitor only sends
the finals into oscillation with lots of hum and a somewhat "dirty" signal.
Am I on the right track here or should I do something different?
Any info appreciated....thanks

Gil n2wjw
--
Remove NOSPAM to reply

Trying to get a higher output reading by adjusting the capacitor only sends
the finals into oscillation with lots of hum and a somewhat "dirty" signal

Gil-

I just came across your message and see no one responded. I'm not familiar
with the alignment procedure for the FT-101e, but had an FT-101B for a couple
of weeks back in the mid 70s. (It caught fire, and I got my money back!)

Do you have an operator's manual and/or a service manual? Your comments lead
me to think you may not be following the correct procedure for tuning the final
amplifier.

As I recall, that type of transmitter had a "Pi-Network" output tuner.
Normally you start with the output capacitor plates fully meshed and tune the
plate capacitor for a dip in plate current. You increase loading by rotating
the output capacitor to un-mesh its plates, and re-dip the plate current with
the plate capacitor. You continue this process until the plate current dip is
at the rated current.

At that point, a neutralization problem is evident when the minimum plate
current does not correspond with maximum power output. If you can adjust
neutralization so they agree, it may solve your problem on that particular
band. You should make the adjustment on the band specified in the manual.

It is also possible that your transmitter is going into a parasitic oscillation
on some radically different frequency. Does the FT-101e have parasitic chokes
connected to the final plate caps? These are normally carbon resistors with a
coil wound around them, perhaps ten ohms two watts with about five turns of
heavy wire connected in parallel with the resistor. It is possible that the
resistors have aged and changed value, upsetting the choking function.

Good Luck.

73, Fred, K4DII

Trying to get a higher output reading by adjusting the capacitor only sends
the finals into oscillation with lots of hum and a somewhat "dirty" signal

Gil-

I just came across your message and see no one responded. I'm not familiar
with the alignment procedure for the FT-101e, but had an FT-101B for a couple
of weeks back in the mid 70s. (It caught fire, and I got my money back!)

Do you have an operator's manual and/or a service manual? Your comments lead
me to think you may not be following the correct procedure for tuning the final
amplifier.

As I recall, that type of transmitter had a "Pi-Network" output tuner.
Normally you start with the output capacitor plates fully meshed and tune the
plate capacitor for a dip in plate current. You increase loading by rotating
the output capacitor to un-mesh its plates, and re-dip the plate current with
the plate capacitor. You continue this process until the plate current dip is
at the rated current.

At that point, a neutralization problem is evident when the minimum plate
current does not correspond with maximum power output. If you can adjust
neutralization so they agree, it may solve your problem on that particular
band. You should make the adjustment on the band specified in the manual.

It is also possible that your transmitter is going into a parasitic oscillation
on some radically different frequency. Does the FT-101e have parasitic chokes
connected to the final plate caps? These are normally carbon resistors with a
coil wound around them, perhaps ten ohms two watts with about five turns of
heavy wire connected in parallel with the resistor. It is possible that the
resistors have aged and changed value, upsetting the choking function.

Good Luck.

73, Fred, K4DII