hammarlund hq-129x hum in audio & weak receive

[mr_fx]

Just got a hammarlund hq-129x last night... it's not doing so well

Broadcast band seems to receive well. 160m is fine... sounds fine on 80m

But much above 40m and it starts to go deaf... infact all I can hear around 10m is what sounds like fm broadcast radio... which is weak


There is a hum in the audio output... and touching the speaker output shocks you

 

[BJ radionut]

Just got a hammarlund hq-129x last night...

But much above 40m and it starts to go deaf... infact all I can hear around 10m is what sounds like fm broadcast radio... which is weak


There is a hum in the audio output... and touching the speaker output shocks you

Well FX welcome to "Old Timer's" radiofun...
I would first say it needs run through the tube tester...
Then by the sounds of things, might need a few caps changed...
Not uncommon for a receiver 60+ years old....

Looks nice well worth saving if your so inclined...but don't expect a 60 year old+ receiver to sound and work as well as a new one unless your willing to spend some time on her....
And as good as that RX is it will NEVER be that good on 10m...it will work but it will never be really good....
15m and 20m will be fair to good....40m and down is where she will "shine"

They need a really good antenna to make them "shine"....but a coat hanger or a "hunk" of wire will make them work...
And like a lot of receivers from that era, most antennas did not use coax they used ladder line and tuners...
Hence a lot of gear from that vintage and older had a 300 Ohm antenna connection blocks on the back and secondary might be an SO239...

Oh yes one more thing....radios that "Glow in the Dark" can have a nasty Kick to them...be careful where you put "things"
All the Best
Gary

 

[Captain Kilowatt]

Like Gary said, that rx will be a bit deaf on 15m and especially 10m. It likely needs a good alignment to bring back some sensitivity and the tubes should be checked. the hummmmmm is most likely due to bad filter capacitors in the power supply. As for getting a shock from touching the speaker output, welcome to Boat Anchors R Us. Sounds like a hot chassis. It may go away or get less of a problem when the filter capacitors are replaced and if not then now you know why modern gear has a three wire grounded power cord connected to the chassis.

 

[wavrider]

Boat anchors r us.

Welcome to the world of old tubes, old caps and carbon resistors out of tolerance.

A good schematic and alignment service manual is a must.

Take your time and make sure you understand every circuit, then align and adjust.

If you can not get an alignment in tolerance then start checking the resistors to see if they are out of tolerance.

Definitely check the filter caps.

some say only replace the bad ones.

I prefer to replace all of the caps. Eliminates problems in the future.

Boat anchors, Put them on the air is fun, the real joy is bringing them back to life so they can be used on the air.

Wear a good pair of shoes, rubber soles if you have them. Never work on an old tuber barefoot. (Don't ask how I know).

 

[Captain Kilowatt]

Never work on an old tuber barefoot. (Don't ask how I know).

I just had a flashback. Bare feet on the basement floor and an old boat anchor with a two wire cord and no isolation transformer. It seemed like an OK idea at the time. It wasn't. :blink:

 

[BJ radionut]

Sometimes a "HOT Chassis" can be cured by "turning the plug over"

Goes back to those days when you NEVER opened the "frige" with your hand on the stove!!!!
and NEVER touch the chassis and the speaker of an old Philco or Silvertone either ladida!
All the Best
Gary (sparky)

As my old Elmer would say "Keep reading BJ"

 

[Captain Kilowatt]

Sometimes a "HOT Chassis" can be cured by "turning the plug over"

Goes back to those days when you NEVER opened the "frige" with your hand on the stove!!!!
and NEVER touch the chassis and the speaker of an old Philco or Silvertone either ladida!
All the Best
Gary (sparky)

As my old Elmer would say "Keep reading BJ"

Good advice Gary. Something that slipped my mind. Actually today most things are doing that. Got home this morning off the night shift and haven't slept yet. It is now 9:00pm. Been up for about 30 hours now. Had 5 1/2 hours sleep since I got up FRIDAY morning. Right now leaning on an old boat anchor chassis may be just what I need to kick start me.

 

[W5LZ]

The HQ-129 was a very fine receiver in it's time. It will probably require some over-hauling, it isn't exactly a 'new-born' anymore. While it won't be absolutely fantastic on the higher HF bands it will certainly do as well as the average receiver now. Of course there'll be some differences but not as much as you might expect. I never had a '129 but did have a '100 (the base line of the Hammerlund series). Wish I had it back...
- 'Doc

 

[k7wxk]

I have a very nice HQ-129 and have had most of the others along the way. I usually start with the AC power cord and work my way down stream. Replace the power cord with a grounded 3 wire cord. Next, I check the power transformer voltages with the rectifier tube removed. Then it's on to the electrolytics. They should be replaced. Once that is done you can replace the rectifier and continue your journey. From here on it is up to you how detailed you get in your restoration. I would think weak RF in the high bands might indicate soft RF and IF tubes or possibly a re-alignment is in order. The HQ-129 manual has a voltage and resistance chart as well as re-alignment procedures. This is a good place to start the post-power supply troubleshooting. Most of the resistors will have drifted high and all the paper capacitors will need to be changed. These are the basic steps in returning a boat anchor to operational condition. Of course, there are always the "head scratchers" where a good magnifier and a curious set of eyes may be the solution. The journey can be a real treat even with the obstacles. The HQ-129 is a great receiver and should provide you many hours of enjoyment.

Disclaimer: My statements are my own opinion and have worked for me with good results, but by no means do they guarantee a risk-free evolution. Consult the manual as well as tips from others who have been there.

Enjoy,
Marc

P.S. My apologies for rambling on about restoration when your original question was about hum in the audio. I had buzz in the audio of the 129 even after changing the electroytics and it turned out to be a bad audio amplifier tube. You might try that.