[Hammarlund] HX-500 trials

[Jeff]

Thanks to all of the great responses!  I didn't think that the socket 
might be the problem.

Alas -

No.  -50 volts on the pin at the top of the socket.  Both of them. I let 
it heat up for a minute to discover both plates on the two 6146s start 
to get red; the "first" one in the pair just draws current faster.

So -- -50 v bias on the tubes, 250 volts on the screen, about 900 v on 
the plates.  Still the tubes draw current.

Open to any other thoughts... tonight I'll put the ammeter on the plate 
choke to see exactly what it is pulling and report back.

And thanks to everybody for the manual information!

Jeff
WB3JIH



On 4/24/2016 7:21 PM, Jeff wrote:
> Oh -- and if anyone has a clean PDF of the manual, let me know.  I 
> appreciate the one on BAMA from N9SOR, but the watermark he's put on 
> it has washed out some of the text on the schematic and 
> voltage/resistance tables.
>
> I'd be glad to trade perfect quality PDFs of the original HQ-140X or 
> the HXL-ONE manual, or Hammarlund HT-32 if you're interested.
>
>
>
>
> On 4/24/2016 7:17 PM, Jeff wrote:
>> Well, been playing on and off with this rig.  Finally reversed all 
>> the golden screwdriver "mods" to the rig and have all the specified 
>> component values in, including the Hammarlund power supply mods now 
>> done correctly.
>>
>> Still, way high voltages on the meter.  Yes, I'm running a bucking 
>> transformer on the input, so I'm only putting about 109 VAC into it.
>>
>> And... now it is drawing current like crazy in standby mode.  As it 
>> warms up, you can hear the power supply start to load then the left 
>> hand 6146 will start to get red.  Reversing the tubes has no change, 
>> always the left one.  So, checked all the components in the power 
>> supply again, replaced all the components in the PA section (some 
>> drifted resistors, but not terribly off), checked wiring and 
>> grounds.  Still the one tube takes off.  Replaced parasitic choke 
>> resistors as the original carbon comps turned to dust in my hands 
>> when I started working them out of the choke. Still the same. Removed 
>> the 12BY7 driver tube, no change.
>>
>> Checked the bias supply -- right on the money with -90 and -50 volts 
>> where it should be.  I do however note that I have over 3 volts on 
>> pins 4 & 6 of the 6146s, when the voltage chart in the manual says 
>> between point 6 and point 9.  About 250 volts at the junction of the 
>> screen resistors.
>>
>> I am able to verify that the 1650 KC oscillators are working, so at 
>> least it appears that I'll be able to get some sections going. It is 
>> also drawing a lot of current though on the LV power supply, and I 
>> haven't tracked that one down yet either. Enough to burn up the two 
>> watt 15 ohm resistor in the LV supply.
>>
>> I also notice now the meter is totally dead.
>>
>> Anybody have any thoughts?  The PA current draw doesn't seem to be 
>> related to the driver section -- the tube's out of the rig...
>>
>> And I thought my CE 100V was a bear to trace out...
>>
>> Thanks for any thoughts --
>>
>> Jeff
>> WB3JIH
>>
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