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K3HVG[_2_] · March 20th 08, 02:16 AM posted to rec.radio.amateur.boatanchors

wrote:
hi guys,
i'm in the process of restoring a 180a. tubes are good, i
changed the electrolytics. rcvr does need a bit of hf alignment but
works well now except for the last problem. so here it is...all
functions work well on the lower bands. when the 2 highest bands are
selected, triple conv. kicks in, am reception works well, but ssb & cw
does not. the ssb audio & the cw notes have a raspy or burbelly(for
want of a better word) sound. i can't understand why, because ssb &
cw work fine on lower bands. i have the bama prints, & poked around
checking resistance & voltages. can't find any far off. any help
would be greatly appreciated. it's a nice vy clean rig with clock &
noise blanker, i have matching spkr also. i want to set up an swl pos.
tnx pete k2iqk

I think you'll find that the conversion oscillator for the upper bands
is the problem. I had to work mine over (read: component re-build), to
include replacing the "good" tube and cleaning the socket. It was a
shotgun re-build but it did cure the problem(s) in the end. The
instability I had was genuinely a pain-in-the-%$#!

Richard Knoppow · March 20th 08, 01:42 PM posted to rec.radio.amateur.boatanchors

"K3HVG" wrote in message
. ..
wrote:
hi guys,
i'm in the process of restoring a 180a. tubes are
good, i
changed the electrolytics. rcvr does need a bit of hf
alignment but
works well now except for the last problem. so here it
is...all
functions work well on the lower bands. when the 2
highest bands are
selected, triple conv. kicks in, am reception works well,
but ssb & cw
does not. the ssb audio & the cw notes have a raspy or
burbelly(for
want of a better word) sound. i can't understand why,
because ssb &
cw work fine on lower bands. i have the bama prints, &
poked around
checking resistance & voltages. can't find any far off.
any help
would be greatly appreciated. it's a nice vy clean rig
with clock &
noise blanker, i have matching spkr also. i want to set
up an swl pos.
tnx pete k2iqk

I think you'll find that the conversion oscillator for the
upper bands is the problem. I had to work mine over
(read: component re-build), to include replacing the
"good" tube and cleaning the socket. It was a shotgun
re-build but it did cure the problem(s) in the end. The
instability I had was genuinely a pain-in-the-%$#!

This is a crystal controlled oscillator operating at
around 2580Khz, you should be able to pick it up with
another receiver to see if its unstable. Keep in mind that
the crystal itself can go bad.

--
---
Richard Knoppow
Los Angeles, CA, USA

exray[_2_] · March 20th 08, 01:58 PM posted to rec.radio.amateur.boatanchors

Richard Knoppow wrote:
"K3HVG" wrote in message
. ..
wrote:
hi guys,
i'm in the process of restoring a 180a. tubes are
good, i
changed the electrolytics. rcvr does need a bit of hf
alignment but
works well now except for the last problem. so here it
is...all
functions work well on the lower bands. when the 2
highest bands are
selected, triple conv. kicks in, am reception works well,
but ssb & cw
does not. the ssb audio & the cw notes have a raspy or
burbelly(for
want of a better word) sound.

ISTR an instance where the LO tube was squirrely and the distortion
wasn't noticeable until you hit the higher bands. Worth a try to sub it
with a known good one.

-Bill

--
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