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 Post subject: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 12:10 am 
Member

Joined: Jan Fri 29, 2021 10:08 pm
Posts: 96
Location: High Sierra > 10,000' elevation
I have a Hallicrafters HT-37 in excellent condition that was recapped.
All the tubes tested fine on my TV-7D/U tester and it powers up fine.

However, when I try to tune it up, I get no meter reading whatsoever and no output in any mode.
I do hear the relay click when set to the MOX position.

When I turn the DRIVER TUNE ans FINAL TUNE controls and advance the RF LEVEL I get no meter reading and no output.

There are no jumpers in the accessory socket and I don't believe I need any to tune it up.

I am not sure what to check next so any advice would be appreciated.

73,
Larry


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 2:19 am 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 11028
Location: Santa Rosa, CA
Is the power supply working? Can you measure DC voltage at the filter capacitors?

Rich


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 2:40 am 
Member

Joined: Jan Fri 29, 2021 10:08 pm
Posts: 96
Location: High Sierra > 10,000' elevation
Hi Rich

I will try that but all tubes tested good and all light up as expected,
and the relay when on "MOX" works so guessing the PS is Okay.

Thanks,
Larry


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 4:49 am 
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Joined: Mar Mon 31, 2014 3:09 pm
Posts: 158
What mode do you have selected? Try CW, not SSB. I would hope you have a dummy load on the output. A power meter between the HT37 antenna jack and the dummy load would give you an indication if the transmitter's meter was dead for some reason.


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 5:07 pm 
Member

Joined: Jan Fri 29, 2021 10:08 pm
Posts: 96
Location: High Sierra > 10,000' elevation
Hi K9DXL

Yes tried all modes including CW and no output on any of them. Yes I have a watt meter connected to a dummy load.

Larry


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Nov Thu 25, 2021 6:30 pm 
Member

Joined: Jan Fri 29, 2021 10:08 pm
Posts: 96
Location: High Sierra > 10,000' elevation
UPDATE!

After checking some voltages, and trying all modes again it starting working!
Got over 80w out. So I believe a contact was probably dirty so used some contact cleaner today. I did think about this, but the radio is so clean, almost no use and still has the original Hallicrafter tubes in it I thought the contacts were fine.

73,
Larry


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Dec Wed 01, 2021 4:08 pm 
Member

Joined: Sep Thu 20, 2012 3:42 pm
Posts: 504
Location: Salem, OR
Larry,

Glad you found the problem. It is very common for many of the boat anchor problems to be contact related. I just finished a Heathkit Sb102 with a similar problem. The cubical relay on the top of the chassis was clean as a whistle to the naked eye, but I shot it with contact cleaner just to be safe, and the problem went away. The stories are endless about dirty band switch and relay contacts in old rigs. Always a good place to start.

Cheers,
Marc-k7wxk


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Dec Thu 02, 2021 4:13 am 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 7976
Location: Liberty, Missouri
I agree with Mark regarding the switches, or ANY metal to metal contact, plugs, tubes, rotary and Toggle switches, phone/mic jacks, etc.

The first thing I always do on any unknown old radio, is to at least exercise ALL the rotary controls at least ten times, lock to lock several times, the first time I fire it up. I try not to use any contact cleaner, only use it as a last resort.

I also very closely watch the input power drain for the first few minutes in case there are power supply or other related problems, its usually stated in the specs page of the manual or often on a sticker on the back of the radio.

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Mike


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 Post subject: Re: Hallicrafters HT-37 No meter reading no output
PostPosted: Dec Thu 02, 2021 2:41 pm 
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Joined: Jun Sun 19, 2011 2:31 pm
Posts: 8073
Like Mike, I exercise all of the switches with a new piece of gear and I will also run all the tube through a tube tester. I am pulling the tubes anyway to exercise the socket contacts and I use the tester to check for shorts and gas but I pay little heed to the "quality" reading even though I am using a good quality mutual conductance tester because the only real test of tube function is whether it works in circuit. A lot of tubes will test fine at DC/line frequency AC but fail to perform properly at RF so a tube tester is often misleading and it will also lead to the trashing of tubes that perform just fine in the set.

Rodger WQ9E


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