Mike Knudsen wrote:

With all the adjustments provided, the VOX inthe HX-50 should work well. It's
nice that it has a built-in antenna relay -- would be a nice match with my
HQ-160 or 180 (though I'd rather use the 180 for AM).

I found the VOX to be pretty decent for an old rig. Of course mine
wasn't an 'old' rig at the time :-)


But the 6146 pinouts and heater voltage will match OK?

Rewire the socket. No biggie. But I'm not recommending this. The
power out of the 6146 was less...its that they were cheaper than the
6BQ6 which didn't hold up all that well. Now its a 'rare' vintage rig
and I wouldn't hose it up.


I haven't cracked the PA cage yet (did Hammarlund own their own screw factory?)
but I trust there's a neatralizing cap in there.

Yes.

What's the purpose of the nice air trimmer cap in the relay compartment below
the PA?

Don't recall...is it the neutralizing cap?



Some rigs (like Viking II or KWM-2) are really paranoid about drawing too much
grid current, especially when tuning up without PA B+ applied. The HX-50
doesn't even have a grid current mode on the meter, so maybe this is less of a
concern?

I don't think you CAN draw excessive grid current with it!


-Bill

- - Bill - - wrote:

6BQ6 which didn't hold up all that well.

Ooops,
6DQ5 neither
:-)

-BM

Well, I found a nice mil/industrial 5R4WGB tube (with special plastic base that
covers up part of the tube), and also DLed the HX-50 manual from BAMA.

Very helpful to know the bias setting (50-60 mA) and how much cathode current
you dare load up (wow, 180 mA, that's a lot, given that a 6146 tops out at 150
-- however, the plate voltage allegedly drops to 600V).

Also that the little knob under hte PA on the relay compartment really is the
neutralizing cap. Beats reaching between the "hot" finals with a screwdriver,
like in those high-priced Iowa rigs.

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up. Hope that compactron isn't dead in one
section. Audio circuit should be easy to troubleshoot, especially since that
portion of the BAMA schematic is actually readable (there is a section with the
ghost of a tube just floating in space, with traces of wires and components
around it). If I need a better schematic copy, I'll ask.

Tnx for the discussion so far -- Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.

Mike Knudsen wrote:


Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up. Hope that compactron isn't dead in one
section. Audio circuit should be easy to troubleshoot,

FWIW, the audio section didn't seem particularly hot in my recollection.
I ran a "piremac" (CB jargon-haha) amplified D-104 with good results
and about 9-10 o'clock in the gain. With any un-amplified mike needed
it to go waay up in my case.

-BM

Well, I found a nice mil/industrial 5R4WGB tube (with special plastic base that
covers up part of the tube), and also DLed the HX-50 manual from BAMA.

Very helpful to know the bias setting (50-60 mA) and how much cathode current
you dare load up (wow, 180 mA, that's a lot, given that a 6146 tops out at 150
-- however, the plate voltage allegedly drops to 600V).

Also that the little knob under hte PA on the relay compartment really is the
neutralizing cap. Beats reaching between the "hot" finals with a screwdriver,
like in those high-priced Iowa rigs.

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up. Hope that compactron isn't dead in one
section. Audio circuit should be easy to troubleshoot, especially since that
portion of the BAMA schematic is actually readable (there is a section with the
ghost of a tube just floating in space, with traces of wires and components
around it). If I need a better schematic copy, I'll ask.

Tnx for the discussion so far -- Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.

In article ,
r (Mike Knudsen) writes:

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up

I got the audio and modulation working, and verified the rig works on SSB and
AM. The problem was a forehead-slapper: when I wnet to feed an audio
generator into the mic lead, I found a dead short to ground. Thinking the
shielded cable from the Amphenol connector to the audio tube had shorted out
(often happens when soldering melts the inner insulation), I lifted the cable's
ground at the tube end. Still shorted.

Then I got suspcious and checked out the mic connector more closely. Turns out
some genius at Amphenol had designed it so that when no mic is screwed onto it,
it shorts to ground! The center contact is on a metal plate that actually
moves in bit to flift the ground when you screw onthe mic cable.

So now I know I have a working HX-50. I'm tepmpted to (temporarily) rewire a
standard 3-terminal phone jack back there, to use my D-104 mic with PTT, and
wire the PTT screw terminal over to the jack. Then I could test the rig on the
air, maybe with the HQ-160 (don't want to risk the HQ-180 on the antenna relay
built into the HX-50 just yet).

Of course before selling the rig I'd put the Amphenol jack back in, right? Or
include it in the package and let the buyer decide?
73, Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.

Mike Knudsen wrote:

Of course before selling the rig I'd put the Amphenol jack back in, right? Or
include it in the package and let the buyer decide?
73, Mike K. AA1UK

In the 'spirit' of 'before selling' after a few days of having it why
not use the rig for a while to get a feel for it. Its not a bad rig and
you might enjoy the fun.

-WX4A

In article ,
r (Mike Knudsen) writes:

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up

I got the audio and modulation working, and verified the rig works on SSB and
AM. The problem was a forehead-slapper: when I wnet to feed an audio
generator into the mic lead, I found a dead short to ground. Thinking the
shielded cable from the Amphenol connector to the audio tube had shorted out
(often happens when soldering melts the inner insulation), I lifted the cable's
ground at the tube end. Still shorted.

Then I got suspcious and checked out the mic connector more closely. Turns out
some genius at Amphenol had designed it so that when no mic is screwed onto it,
it shorts to ground! The center contact is on a metal plate that actually
moves in bit to flift the ground when you screw onthe mic cable.

So now I know I have a working HX-50. I'm tepmpted to (temporarily) rewire a
standard 3-terminal phone jack back there, to use my D-104 mic with PTT, and
wire the PTT screw terminal over to the jack. Then I could test the rig on the
air, maybe with the HQ-160 (don't want to risk the HQ-180 on the antenna relay
built into the HX-50 just yet).

Of course before selling the rig I'd put the Amphenol jack back in, right? Or
include it in the package and let the buyer decide?
73, Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.

In article ,
r (Mike Knudsen) writes:

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up

I got the audio and modulation working, and verified the rig works on SSB and
AM. The problem was a forehead-slapper: when I wnet to feed an audio
generator into the mic lead, I found a dead short to ground. Thinking the
shielded cable from the Amphenol connector to the audio tube had shorted out
(often happens when soldering melts the inner insulation), I lifted the cable's
ground at the tube end. Still shorted.

Then I got suspcious and checked out the mic connector more closely. Turns out
some genius at Amphenol had designed it so that when no mic is screwed onto it,
it shorts to ground! The center contact is on a metal plate that actually
moves in bit to flift the ground when you screw onthe mic cable.

So now I know I have a working HX-50. I'm tepmpted to (temporarily) rewire a
standard 3-terminal phone jack back there, to use my D-104 mic with PTT, and
wire the PTT screw terminal over to the jack. Then I could test the rig on the
air, maybe with the HQ-160 (don't want to risk the HQ-180 on the antenna relay
built into the HX-50 just yet).

Of course before selling the rig I'd put the Amphenol jack back in, right? Or
include it in the package and let the buyer decide?
73, Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.

In article ,
r (Mike Knudsen) writes:

Everything seems to work, except no modulation on SSB or AM -- that is, no
increase in RF out or DC in when I zap the mic center pin with a screwdriver,
with the AF gain turned full up

I got the audio and modulation working, and verified the rig works on SSB and
AM. The problem was a forehead-slapper: when I wnet to feed an audio
generator into the mic lead, I found a dead short to ground. Thinking the
shielded cable from the Amphenol connector to the audio tube had shorted out
(often happens when soldering melts the inner insulation), I lifted the cable's
ground at the tube end. Still shorted.

Then I got suspcious and checked out the mic connector more closely. Turns out
some genius at Amphenol had designed it so that when no mic is screwed onto it,
it shorts to ground! The center contact is on a metal plate that actually
moves in bit to flift the ground when you screw onthe mic cable.

So now I know I have a working HX-50. I'm tepmpted to (temporarily) rewire a
standard 3-terminal phone jack back there, to use my D-104 mic with PTT, and
wire the PTT screw terminal over to the jack. Then I could test the rig on the
air, maybe with the HQ-160 (don't want to risk the HQ-180 on the antenna relay
built into the HX-50 just yet).

Of course before selling the rig I'd put the Amphenol jack back in, right? Or
include it in the package and let the buyer decide?
73, Mike K. AA1UK

Oscar loves trash, but hates Spam! Delete him to reply to me.