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.