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Re: Parting out a SX 62
i have a few parts for the sx 62A and SX 42 . send me a list of what you73 Tony Anthony W.(Tony) DePrato WA4JQS Extra Since 1962 CQ DX HALL OF FAME #35 HONOR ROLL CW RTTY PHONE #1 MOST WANTED VP8SSI 1992 #1 MOST WANTED 3Y0PI 1994 Founder :South Sandwich Island DX Group Founder : Ky Dx Group WA4LLK 1988 Founder: Lake Cumberland Amateur Radio Assoc. 1974 Calls Held: VP8SSI VP8BZL 3Y0PI V31SS ZD8JQS WA4JQS/4K1 WA4JQS/KC4 WA4JQS/ZS1 |
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Re: HT45 Loudenboomer working now with new power supply
Thanks for tips Rick!
Nice job on yours. Working on mine has been delayed by a broken tooth. I'm hoping to play with it by Saturday. Serendipitously picked 15k and 50k 100W resistors at the same hamfest! Have a Heathkit high voltage probe. The 866As were replaced with a pair of solid state rectifiers. It looks like that's as far as? it went because the new HV is not connected to anything and there's no visible damage. I'm hoping all is good.? I acquired this HT45 thinking It will make a nice 6m conversion. Got it home and decided it's too nice.? 73, -bob ah7i em73ts "boil your water" Atlanta |
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Re: HT45 Loudenboomer working now with new power supply
If you're using the original swinging choke input supply, remember that you cannot "test" it unless you have it connected to the amp or you add additional bleeder..
I wouldn't use the amp(for testing)? until I know for sure everything is ok in the PSU.? An easy way to do it is to temporary install additional bleeder resistor(s) in the power supply to approximate the reduced idling plate current of around 45-50mA If your power supply is original, it should do somewhere around 3000v.? The original bleeder is 210k I=V/R ? or 3000/210000 = approx 14.3mA? So you need around 45mA or so additional draw on the power supply to get the swinging choke swinging!? (Halliscratch did it with the final tube in the amp when the "jumper" on the back of the RF deck was in place)? The additional resistor needs to be in parallel with the 210K ?For 45mA.......R=V/I or 3000/0.045 or roughly 67K? AND since it's going to get pretty hot, it needs to dissipate some serious power.? P=Vsqr /R? Or 3000 * 3000 /67000 = 134W Or if you prefer I(squared) * R ?? (0.45)SQR x 67K Since you're not leaving it powered for long periods of time, you can use lower power resistors for short periods of voltage measurement.? You could even use? 50K resistor but the current will be higher and it's important to use 67K because this approximates the 40-50mA the tube will draw in standby USE? A HIGH VOLTAGE PROBE, I got this one: BK PR 28A 40kV High Voltage DMM Probe I think I gave about $40 for mine.? I know they're more expensive now.? But don't skimp on something that could end your life!! Hook everything up and stand back! then throw the switch.? (keep one hand in your pocket!!!) If you try to test it with the amp and the (idling) current draw is low (below that which would make the choke work properly)? for some reason, the plate voltage could likely exceed 4000V and destroy the meter, oil capacitor and other components in the amp...... so it's imperative that the power supply is "right" before you hook up the RF deck -- 73/Rick W4XA __________________________________ All posts are created using OpenSuSE Leap 15.5 x64 Linux |
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Re: HT45 Loudenboomer working now with new power supply
I am also a proud owner of a Loudenboomer, but it has been many years since power was applied to it.
I need to recap the power supply. I don't want exploding capacitors and magic smoke. This is an original Hallicrafters power supply for the amp, and original owner (W8DCL Walt-SK) rebuilt it 25+ years ago. I love the mods, the jones plug and all, and may do the same to mine. -- 73 de w8nsi Jim TS480SAT, Hallicrafters HT45 Loudenboomer Mk2 amp 80m loop, 40-10 efhw, 4BTV vertical, Tennadyne TD-160 |
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Re: HT45 Loudenboomer working now with new power supply
A'hem.....
I think I am going to need a picture of this to believe it!! Halli put a 150ohm resistor in the cathode circuit to reduce the idling current to 40mA or so. (select/deselect with the T/R relay via the jumper terminal in the back of the RF deck) The whole reason for that was to provide current to get the swinging choke to "swing" because it needed a minimum of 55mA or so.? 210k bleeder @14.2mA plus reduced idling 3-400 @40mA and the choke would "choke"......without that swinging choke action, the voltage was 4000-4500V (capacitive input voltage for a full wave + 6750 CT secondary) This is the main reason I completely rebuilt the power supply using the Drake L-4B plate transformer plus capacitor input filter. They literally used the reduced idling current as a power supply bleeder! Once you have a PSU that doesn't need a lot of bleeder current, you can change that 150 ohm resistor to a 15K resistor effectively cutting the tube off during STBY/receive If I had it to do over (and had a higher voltage PW Dahl $500 transformer) I would use it to get about 3500volts! When I tried 3-400's in my Drake L-4B, (At L-4B plate voltage) they performed identically to the 3-500's With my "new" HT-45 power supply, running on 240VAC line voltage (245V) I was seeing 600W output from loudenboomer. I made my own "cable".? The only voltages in the cable (except the HV) are 120VAC.? The HV wire I used is solid core ignition wire that is probably good for around 20kV or more.? No problem with it inside the vinyl hose I put it all in. I also installed an 8-pin jones plug (like the L-4B uses) Made the mount for the jones socket out of thick phenolic Then added a 240V power inlet for the power cord. -- 73/Rick W4XA __________________________________ All posts are created using OpenSuSE Leap 15.5 x64 Linux |
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Re: HT45 Loudenboomer working now with new power supply
Rick and Gentlemen,
I hope to answer yes in a few days. I collected one just this Saturday. Worked a 13 hour shift yesterday(Sunday). Have to snail mail the balance of what I am paying for it this AM. Hope to get some time for a detailed inspection later today and will post findings.? I am surprised at a 3kV plate supply bundled in with the rest of the wires in the power supply cable. 1964 :-) !! Manual says it's OK for the 3-400Z to idle with 120mA Ip. 360W idle on a 400W tube. A shack warmer for sure. 73, -bob ah7i em73ts Atlanta GA |
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Re: Halicrafters SX17 transformer
开云体育Too bad we cant get clamp on miniature DC scope probe ?or dc ammeters? at pauper prices; then a guy with a running SX-17 could just peep inside the B= wiring.
?On 5/30/2024 6:44 PM, Jim Whartenby via groups.io wrote: _._,_._,_ ._,_ -- don??? va3drl |
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Re: Halicrafters SX17 transformer
开云体育John ,? my tendency is to take it up on a variac and watch the primary milli-Amps, often with the rectifier or maybe all tubes removed. Just a small magnetizing current should show up if it is good—no shorted turns. ? From: [email protected] [mailto:[email protected]] On Behalf Of John via groups.io
Sent: Friday, May 31, 2024 6:48 AM To: [email protected] Subject: Re: [HallicraftersRadios] Halicrafters SX17 transformer ? I finally managed to pry open the lid at the top of the receiver. It was seized with age and at first I didn’t want to use too much force so as not to cause any damage. However, opening it up was necessary if the radio was to be repaired and with careful levering and a bit of effort, thankfully it did finally pop open with no damage done. I don’t know whether one can post photos on here, but now that I can see the top side of the transformer, it is much bigger than imagined. It also has a sort of tag strip on top marked with different voltages, from 250V to 110V, so it can be configured for use on UK mains. The fly lead with the ‘bullet’ connector was slid into the 250V tag which would be correct. I pushed the connector out and back in a couple of times and then read about 15 ohms across the mains cable. It seems that my initial suspicion of an open transformer may have been premature and erroneous. _._,_._,_ ,_ -- don??? va3drl |
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Re: Halicrafters SX17 transformer
Well, he says sheepishly, this is true for the Thordarson, 50-60 cycles.? The PAECO frequency range is from 50 to 1000 cycles.??I still think the PAECO is the all around winner, if this is a contest. Rechecking the?Stancor, it does say 60 cycles but the bigger mistake is in the B+ current rating.? I should have said the Stancor P-6013.? The difference is 90 vs 120 mA.? This may be a problem when the cost is driving the spec.? Less copper, less iron, lower price. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Thursday, May 30, 2024 at 07:36:07 PM CDT, Jim Whartenby <old_radio@...> wrote:
Yes. according to the catalog, 50-60 cycle Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Thursday, May 30, 2024 at 12:08:20 PM CDT, don Root <drootofallevil@...> wrote:
Jim, are these 50 cycle ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Thursday, May 30, 2024 11:18 AM To: [email protected] Subject: Re: [HallicraftersRadios] Halicrafters SX17 transformer ? John There are various catalogs from replacement transformer manufacturers, I looked at STANCOR and THORDARSON, for example.? There are others.? I have not looked at my junque box so there are still other possibilities. ? STANCOR? model PC8420 / PM8420 (same transformer, different mounting) has the following specs: 2 1/2 inch by 2 9/16 mounting hole spacing 325 - 0 - 325 volts @ 150mA 5 volts @ 3 amps 6.3 volts @ 5 amps ? THORDARSON? model 22R05 2 1/2 inch by 3 1/8 inch mounting hole spacing 300 - 0 - 300 volts @ 120 mA 5 volts @ 3 amps 6,3 volts @ 5 amps ? Another transformer of interest is the one found in the Hewlett-Packard 200CD audio oscillator.? This might be available either locally to you or on eBay?? It has 115 - 230 volt split primary windings which is a plus. PAECO model 910-94 2,5 inch by 2.34 inch mounting hole spacing 315 - 0 - 315 volts @ 125 mA 5 volts @ 2 amps 6.3 volts @ 3.55 amps.? It should do 4 amps with no trouble. This is an over designed power transformer with very conservative ratings so it should fit the bill but it's mounting is upright not horizontal like that in the SX-17.? It also contains a 8H @ 125 mA filter choke.? The manual is available on-line, with photos.? I have a history with this transformer. ? Regards, Jim ? ? Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Thursday, May 30, 2024 at 05:28:29 AM CDT, John via groups.io <siloam@...> wrote: ? ? I completely forgot about noting the current on the low voltage windings! I added up the heater currents and arrived at the same 3.9A that you did. In addition to this, according to the data-sheet, the heater for the rectifier on the 5V winding takes 3A.
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Anthony W. DePrato
Bob ah7i
Rick W7IMM
W8NSI James
don Root
Jim Whartenby