[Hallicrafters] Problem with HT-32A

[rbethman]

My thoughts would be to pull the relay.

Remove its cover, and burnish the contacts.

They develop a later of oxidation over time.

There are actual burnishing tools, but an old reliable stand-by is a 
dollar bill.  Due to its linen bases and the fibers within, it does a 
marvelous job on relay contacts.

Give that a go, and let us know if this begins bringing the radio back 
to kife.

Bob - N0DGN

On 3/5/2012 6:57 PM, Al Parker wrote:
> Hi Burt,
> 	Haven't heard from you in ages, sorry it's with a problem now ;-)
> 	My HT-32 ha a Peter Dahl xfmr too, nice, big, shiny, as you say.  Is
> your doing this on all bands?  How long's it been since it was working
> OK, and what's been done just before it quit?  The steady -49 bias
> voltage, if it's rock steady, would indicate to me that you're not
> getting any drive to the finals.  Mine changes some with a signal.  The
> meter is just an output monitoring meter, not plate current, so with no
> indication there, it says the same.  It won't indicate just a small
> amount of power.  The band switches are prone to getting cruddy with
> lack of use, maybe just exercising it several times from end to end
> would help.
> 	Do you here any signal at the output freq. when you key it, on CW or
> DSB?  If so, there's probably some signal getting at least to the
> driver, maybe it's bad.  If not, you'll need to look further back.
> 	That's a little bit to look at&  think about,  Let us know what you
> might find as you get into it.
> 	I've had mine on the air on the Vintage Sideband Net for the last few
> weeks, and Bob, W9RAN, has had his on also.  We've both made an ALC mod.
> that was in a CQ mag "way back", and it seems to be helping keep the
> signal level up, without overdriving.
> 73,
>
> Al, W8UT
> www.boatanchors.org
> www.hammarlund.info
>
> "There is nothing -- absolutely nothing -- half so much
> worth doing as simply messing about in boats"
> Ratty, to Mole
>
> On 3/5/2012 6:35 PM, K4PRF - Burton Pratt wrote:
>> This is a beautiful HT-32A with a big shiny Peter Dahl power transformer
>> installed a few years back.  It was operating fine but just quit making
>> any power.  I have checked all the voltages and tube base resistances.
>> All are very close to specks.  I have to admit that I don't understand
>> how the transmit keying is accomplished other than through the vox
>> relay, cw key or calibrator control.  None of these are keying the
>> transmitter.  No motion on the meter.  It is as if the RF power section
>> was just turned off.  I think something is killing the bias control of
>> the driver and output tubes.  When I try keying the transmitter I can
>> hear the relay operate but the grid bias on the 6146s holds at around
>> -49 volts.  I know all about the problem with the 5V4s originally used
>> in the low voltage supply.  I use 5R4s in this transmitter and in my
>> HT-37.  This transmitter is in original condition except for the power
>> transformer and the bias diode.  All of the caps are original.  Tubes
>> all check good on a TV-7 but I have substituted all with no change.  I
>> have not touched the alignment at all .  I'll bet that I am not the only
>> person that has run up on this problem so any suggestions will be
>> greatly appreciated.
>>
>> 73,
>>
>> Burt,  K4PRF