I checked the HT37 and it only had one xtal in it. Just so happened to be 32.000

Hi Richard. I have a HT37 chassis with lots of parts still. I will check and see if the xtal is still there. If so, it's yours. I will try to head to the shack in a few hours to check.

Greetings,

Would anyone happen to have a 32.000 MHz Crystal for the HT37 they are willing to sell?

From the manual:



Thanks in Advance,
Ricky KR7W

I would be interested in the HT-4 if it becomes available. Please feel free to PM me.

Thanks
Gary

So I sold my BC-610E? last month here in Michigan.?
It was on the air as a daily user when I sold it. 100% complete. 614 SA, some spare 250THs, coils for 20, 40, 80 and 160m plus manuals.
I let it go for about $500 I think.
It is on the air at its new home and I hear it often, so it's well cared for.
In my opinion, it was more important to me that it went to someone who was really going to put it on the air, rather than be put in storage somewhere.
My .02?
73
W8tow

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Joe, thanks but I got what I needed, # 40 bulbs.

K2WH

Someone was looking for screw-in type bulbs. If a #46 will work, contact me direct via
WS?E ON QRM.COM? OR? ARRL.
Joe, WS?E, TX

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Hi Jim,

Thanks for the info!? It appears that I was replying when you were and then, I left the computer sitting without pushing the "SEND" button!? So you can see my what I discovered experimenting? below!

I absolutely did (first) power it up using only the existing bleeder !? I of course discovered exactly what you're talking about!?? The NE51 was not installed at the time.? Everything is disconnected? and standing alone.? I am using 2 SEMTECH 5000v diodes in place of the old 866A's and the filament transformer is also gone.

Again, I am still concerned that the 40ma of additional current draw due to the tube will not result in enough current to make the choke work but I will try it.? If I have to add a little more bleeder, I can easily add another 100K.? The NE51 I have is in fact an NE51H

I do have a good tube (actually I have 3!!)?? I tried all of them in my L-4B and they all do at least as good as the 3-500's I have in it now.? (same roughly 1300w out)?

As an aside, the Eimac 3-500's I have fit perfectly (slightly shorter than the plate choke)? in the HT45 so I am tempted to use one of them and just use the 3-400's in the L-4B but that's another thread to discuss!!

Anyway, I am going to do exactly what you're suggesting.? I am going to try it with the HT45.? If the voltage is "ok", I'll leave it alone.? If the voltage is still high, and an additional 100K doesn't work,? (maybe the choke is NOT actually the original choke, or it's defective) ? I may just see if I can get another swinging choke.? If I cannot find one, I am going to use the extra Drake L-4PS I have.? (it's less than ONE HALF the size of the PS-2V!!)

The downside of using the L-4PS is the 2700 no-load voltage.? I think the 3-400 (or 3-500)? will work pretty good with 3200-3400v?


73/Rick
WA6III

__________________________________
No critters were injured transmitting with Hallicrafters transmitters except
the ones that wandered into the final amp cage Bug-Motel!!
Bugs check-in, but they don't check-out!

Howdy,

Thanks for the reply

Well, since the voltage across the choke is dependent on the current through the choke, it shouldn't make any difference. Position of the choke in the circuit, positive or negative doesn't really affect the voltage "across" the choke.? It only changes the actual voltage on the windings referenced to the grounded iron core

Putting it in the negative lead would only take the high voltage off the windings (which is certainly desirable).... but I don't think the "snapping" is due to "winding-to-core" arcing.? If it was, it would likely be continuous.? I.E., it would short, stay shorted and pop the fuse.?

This is more a "clicking", snapping", ticking that I think is due to internal arcing across windings (or the arc "gap" depicted in the schematic) and that voltage is directly related to the (pulsating) current in the windings.


Either way, my original question is more related to the the idling current when the amplifier is in the STBY mode.? (I know what it should be in the transmit mode.....It should be around 120ma, and that's more than enough current for the choke)

And in fact, I went back to the manual and read a little closer and actually found what I was looking for!



I guess I should just RTFM? before asking questions!!? But at 40ma, I'm thinking it's not going to be enough unless I add an additional bleeder.

I found that using only the power supply bleeder resistor of 210k Ohm (with only an 18ma draw) , the voltage was high at around 3750+ volts.? (and there was "ticking")?

When I added an additional 100K in parallel,? I still had around 3750+ volts ,? total resistance around 68K,? resulting in a total 55ma draw (still ticking!!)

When I added an another 100K in parallel, I saw a significant voltage drop.? Voltage was 3460v, no ticking, with a combined resistance of about 40K.

Total current draw due to the total 40K (210K + 100K + 100K parallel) was around 86ma.

I know choke input power supplies have a lower limit of current that must be present to prevent the voltage from "soaring" (ARRL handbook term!)

The part that I am concerned about is that since the tube will draw 40ma (according to the instruction above) when the T/R "jumper" is removed, that's only going to be a total of about 18ma + 40ma? =? 58ma.

If you note above that I still had "ticking at 55ma, I am having a hard time believing that 3 additional ma will be the "break-point" of where the choke starts to "choke"

Maybe it will.?? This is where my lack of experience with high voltage (swinging) choke input supplies is somewhat lacking.?

I would REALLY like to hear from someone else that actually has or has played with one of these power supplies hooked up to an HT45? so I can compare notes!

Hi Rick!

?? In looking over the power supply schematic and in view of my own experience with a PS-500 power supply, I think I can safely say that Hallicrafters did not know how to design power supplies.

?? First, a caution:?? This PS-2A power supply is not intended to be operated without a load and in the absence of proper connection to the HT-45 amplifier.?? If you do so, all bets are off.?? Note that with the power supply disconnected from the amplifier, there is no negative return for the high voltage.?? The high voltage should therefore be about 1700 volts positive with respect to the chassis and the negative lead (Pin 7 on TB2) should be about negative 1700 volts with respect to ground.?? However, this assumes that the insulation all the way around is perfect, which it likely isn't.?? There is supposed to be 1/2 ohm of at least 2 watts power rating between this negative lead and chassis ground.?? This is formed by the plate current metering shunt resistors in the amplifier when it is connected to the supply.?? Absent the amplifier being connected, who knows what is arcing where and what is causing your noises.

?? According to the manual, the idling current with the extra resistor in place is about 40 mA.?? Since this will change the output voltage of the power supply, we are dealing with one equation in two unknowns, so experimentation would be required to discover what sort of external resistive load would draw 40 mA.?? Until you figure this out and connect a suitable external load and a suitable ground to the negative of the HV supply you cannot determine the operating parameters of the power supply.?? The best test is to operate it with the amplifier as a load.... however, this assumes that the 3-400 is good and at least the DC portions of the rest of the amplifier circuitry are correct.

?? The circuit calls for an NE51 to be connected across the 10K bleeder in the power supply.?? Using Hallicrafters figures for the B+ (3,000 volts) the rated current of the lamp would be exceeded and the lamp should be destroyed.?? For higher voltages such as you are experiencing, the condition is even worse.?? An NE51H MIGHT survive here, but is not specified in the parts list.

?? I wish you the best of luck in getting the thing working; hopefully you will not have to do too much re-engineering.

Regards,
--
Jim T.
KB6GM