Hammarlund HX50 6DQ5 Plate choke question.
 

Gents,
I am restoring an HX50 for a friend. It appears that someone has modified
L115 (wrapped around R181, 47 ohm 1w) by altering the amount of turns in two
ways.

1) Inspection of the solder ends where the inductor (L115) is soldered to
the resistor's lead wire appears to have been changed. Extra overlapping
wire, as though someone shortened the total length of the inductor's wire,
has been adjusted and soldered to the resistor's lead wires.

2) Solder blobs have been placed on the inductor as to short out two of the
turns.

Please see pictures at the bottom of page:
http://www.ppinyot.com/hammarlund.htm. Sorry for the fuzzy blow ups. I do
not have a close up Macro lens available at this time.

Can someone tell me the proper quantity of turns the inductor L115 should
have, wrapped around R181, 47ohm 1w resistor? And/or send me a picture of
an operational unit?

It would be a big help to have this worked out before +700v, alignment and
calibration.

Thanks,
Paul
kb3lzp.

Hammarlund HX50 6DQ5 Plate choke question.
 

I would just remove the solder blobbed winding and replace it with the
same gauge wire with the same number of turns as the original. Perhaps
time for a nice, clean new resistor as well.

It's a parasitic choke to suppress VHF oscillation and should not be
that critical.

Just replicate the original and everything should be OK.

John

Hammarlund HX50 6DQ5 Plate choke question.
 

It could be the choke had too much inductance on 10 meters,
and the resistor showed signs over heating; or even parasitic oscillations
could have caused issues with the resistor overheating. Most hams
would "tinker" with the circuit in an attempt to stumble on a "cure".
I'd wonder if the orignal plate chokes are still in place?

Pete

Hammarlund HX50 6DQ5 Plate choke question.
 

Thank you guys for the replies. The origonal plate choke is still in place
and has decent DC resistance. I have removed the solder bridges with some
solder wick, checked the 47 ohm reistor and it is OK. Also reserch in the
ARRL 200 and 2006 books explains the use of this choke, its different
configurations and how to test an amp for indication s of parasitic
oscillations.

Thanks for ths clues on how to resolve this problem. Your direction helped.
I will report back later and let you know how the initial restoration
alignment and burn in goes.

Paul.