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Re: New to Group
开云体育Ahh Jim ?, yes I guess it means that too many.? I use pre-octal [it doesn’t sound so demonstrative], but I am trying to confirm that I was really sending what the AI experts know. Do you agree with them? ? Back to the 5-T, I would agree, about the tubes suggesting that it was designed perhaps before about ?may, june, july 1935 ?when the new octal tube data became known the first ad I saw for the 5-T?? was in: ?? ?somewhere,??? BUT a bigger one was in: ??? ?? pdf page 8??? ? ?still?? Marion???? Indiana I just wonder they used all the new octal/metal sockets and tubes for the ?flagship Super sky-riders and left the older stuff for the sky buddy. That might make good business sense. I worked in an industrial electronic plant for a while, so I wonder who bends and punches the steel chassis, front panel, and cabinet ? were machines easily available to do some bends?? Maybe it depends on just what is available? maybe they contract out the steel, maybe not The month after this last ad, they changed the address to 2611 indiana so the first 5-Ts might be made at either place ? Wandering back to the early skyriders, and where they were actually made; nobody seems to have evidence of what happened to the SMI license from RCA when the they split up in Oct 1932. ??? ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Wednesday, April 2, 2025 6:00 PM To: [email protected] Subject: Re: [HallicraftersRadios] New to Group ? Don By "big pin" I was referring to tubes that were common before the arrival of the octal tube around 1935.? The hallicrafters 5T uses all pre-octal tubes found in the RC-11 RCA tube manual (circa 1933) so it's design was completed before the octal tube was available to the radio designer.? The 5T must have been on the drawing board of a company bought by hallicrafters or it was the pet project of an early hallicrafters employee. ? Sorry for the confusion and the use of the term, I assumed that everyone was familiar with this?idiom. Jim ?
? ? _._,_._,_ -- don??? va3drl |
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Re: New to Group
开云体育Richard,? loctal /? loktal? ..s were spoken about ?in this? 1938-12 article: ? pdf??? 20?? -----
but ?March 1939 revealed some data ? pdf?? 59??? ----- From some reading it seems that RCA? and philco? were in a battle so philco started a deal with Sylvania ??much earlier maybe ?? Probably, the RF tubes for TV is what drove the loktal design ahead of octals due to lower ?capacitance ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow via groups.io
Sent: Wednesday, April 2, 2025 6:20 PM To: [email protected] Subject: Re: [HallicraftersRadios] New to Group ? Turns out that octal base tubes were introduced by General Electric -- don??? va3drl |
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Re: Need help with HT-40 MK 1 troubleshooting
开云体育
The -50 vdc on the grid is the effect?of grid leak bias. It is developed across R9 and R10. It will only reach -50vdc with proper drive and normal power output.
Walt Cates, WD0GOF
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From: [email protected] <[email protected]> on behalf of Larry - WA2DGD via groups.io <wa2dgd@...>
Sent: Thursday, April 3, 2025 6:09 PM To: [email protected] <[email protected]> Subject: Re: [HallicraftersRadios] Need help with HT-40 MK 1 troubleshooting ?
Hi Joe,?
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Thanks for the reply.
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I left a few things out in my first post.?
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As you suggest, I have RF at V1, same as the crystal frequency, 7.125. I can trace the rf signal all the way from the oscillator, to the buffer, thru the bandswitch and to the grid of V2 pins 1,5. I can see the 7.125 signal at the output of V2 and the
SO239 connector. The biggest issue the grid drive, looks like V2 pin 1,5 should be -50vdc and I only have -5.00vdc. I'm not sure where the -50vdc originates.
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The power supply is giving me over 585 vdc on a VTVM in AM and the same in CW, the schematic shows 430 vdc CW and 500 VDC AM. I'm not sure these are off due to the problems with the Grid Drive. The 210 vdc at V1 pin 8 is much higher, almost at supply voltage,
575vdc and the 12k measures good. Also pin 9 is at same voltage as pin 8. ?
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As suggested in a previous post, I can trace the -5vdc Grid from V2 back thru the switched inductors and bandswitch, but I can't find -50vdc anywhere.
Both neon lamps are working, the original under chassis one was blown and I replaced it, I can see both flash when I turn the rig on or off.
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I thought possibly C19 shorted and was pulling down the voltage, I disconnected it, voltage rose to -15vdc but it tested at 9pf on my capacitance meter. I replaced it.
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Thanks for the help. If you think of anything else, please let me know.
?
Regards,
Larry
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Re: New to Group
Don By "big pin" I was referring to tubes that were common before the arrival of the octal tube around 1935.? The hallicrafters 5T uses all pre-octal tubes found in the RC-11 RCA tube manual (circa 1933) so it's design was completed before the octal tube was available to the radio designer.? The 5T must have been on the drawing board of a company bought by hallicrafters or it was the pet project of an early hallicrafters employee. Sorry for the confusion and the use of the term, I assumed that everyone was familiar with this?idiom. Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Wednesday, April 2, 2025 at 04:20:18 PM CDT, don Root <drootofallevil@...> wrote:
Hi Jim, I have been trying to reply but keep getting diverted. One problem is understanding the definition of a “big pin” tube. How big is “big”? ?I can find no definition. the 4,6,and older 7 Ing tubes have two ?0.156 ?[5/32?] inch pins and some .125 [1/8]inch pins but the 5 pin tube has only the smaller pins. ? Anyhow, I googled with “what is? a "big pin" radio tube?” ????and AI replied as follows” AI Overview A "big pin" radio tube, also known as a vacuum tube or electron tube, is a type of electronic device that uses the flow of electrons in a vacuum to control electrical signals, often used in older radio and audio equipment.? Here's a more detailed explanation:
A "big pin" radio tube is a type of vacuum tube, a device that uses the flow of electrons in a vacuum to control electrical signals.? ·? ·? How it works: Inside the tube, a heated filament (cathode) emits electrons, which are then controlled by a grid (a metal mesh) and attracted to a positively charged plate (anode).? ·? ·? Why it's called "big pin": The term "big pin" likely refers to the size and shape of the base or connector pins on the tube, which are larger than those on smaller tube types.? ·? ·? Examples: Some common "big pin" tube types include the 6L6, 6V6, 6K5, and 6C5.? ·? ·? Historical Context: Before the advent of semiconductor devices, vacuum tubes like these were widely used in various electronic applications, including radios, audio amplifiers, and television sets.? ·? ·? Modern Usage: While largely replaced by transistors and other solid-state devices, vacuum tubes are still used in some applications, particularly in audio amplifiers and specialized electronic equipment where their unique sound characteristics are desired.? ? More stuff later. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, March 23, 2025 11:49 PM To: [email protected] Subject: Re: [HallicraftersRadios] New to Group ? AFAIK, all of the hallicrafters listed below have metal front panels and are housed in metal cases.? The S-10 / SX-10 did have an optional mahogany?case that the metal case slipped into but I doubt that any were actually sold.? If the production numbers are correct, at one time I owned 1.5% of production!? That would be three of them out of some 200 reportedly made. Still have two. ? The 5T is an odd one.? It uses all big pin tubes so it is obviously a much earlier design.? It is either the first or fourth superhetrodyne design sold by hallicrafters. ? hallicrafters receiver models Information gleaned from Max de Henseler and Chuck Dachis books S-1, S-2, S-3 TRF-regen, 5 tubes, manufactured by Silver-Marshall?, 1934 ++++++++++++++++++++++
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? _,_ -- don??? va3drl |
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Re: New to Group
开云体育Hi Jim, I have been trying to reply but keep getting diverted. One problem is understanding the definition of a “big pin” tube. How big is “big”? ?I can find no definition. the 4,6,and older 7 Ing tubes have two ?0.156 ?[5/32?] inch pins and some .125 [1/8]inch pins but the 5 pin tube has only the smaller pins. ? Anyhow, I googled with “what is? a "big pin" radio tube?” ????and AI replied as follows” AI Overview A "big pin" radio tube, also known as a vacuum tube or electron tube, is a type of electronic device that uses the flow of electrons in a vacuum to control electrical signals, often used in older radio and audio equipment.? Here's a more detailed explanation:
A "big pin" radio tube is a type of vacuum tube, a device that uses the flow of electrons in a vacuum to control electrical signals.? ·? ·? How it works: Inside the tube, a heated filament (cathode) emits electrons, which are then controlled by a grid (a metal mesh) and attracted to a positively charged plate (anode).? ·? ·? Why it's called "big pin": The term "big pin" likely refers to the size and shape of the base or connector pins on the tube, which are larger than those on smaller tube types.? ·? ·? Examples: Some common "big pin" tube types include the 6L6, 6V6, 6K5, and 6C5.? ·? ·? Historical Context: Before the advent of semiconductor devices, vacuum tubes like these were widely used in various electronic applications, including radios, audio amplifiers, and television sets.? ·? ·? Modern Usage: While largely replaced by transistors and other solid-state devices, vacuum tubes are still used in some applications, particularly in audio amplifiers and specialized electronic equipment where their unique sound characteristics are desired.? ? More stuff later. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, March 23, 2025 11:49 PM To: [email protected] Subject: Re: [HallicraftersRadios] New to Group ? AFAIK, all of the hallicrafters listed below have metal front panels and are housed in metal cases.? The S-10 / SX-10 did have an optional mahogany?case that the metal case slipped into but I doubt that any were actually sold.? If the production numbers are correct, at one time I owned 1.5% of production!? That would be three of them out of some 200 reportedly made. Still have two. ? The 5T is an odd one.? It uses all big pin tubes so it is obviously a much earlier design.? It is either the first or fourth superhetrodyne design sold by hallicrafters. ? hallicrafters receiver models Information gleaned from Max de Henseler and Chuck Dachis books S-1, S-2, S-3 TRF-regen, 5 tubes, manufactured by Silver-Marshall?, 1934 ++++++++++++++++++++++
?
? _,_ -- don??? va3drl |
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Re: HT-37 CW Break-In Modification
Ed This is surprising.? The maximum service line voltage is 126 volts per ANSI C84.1.? This maximum line voltage has not changed at all since it was first published in 1954.? This is when the 120 volt ac line voltage convention was adopted.? The two previous line voltage conventions are 115 volts +/- 10% issued in 1926 and 117 volts +/- 7.5% issued around the beginning of WW2. The only voltage that really matters in tube powered equipment is the heater voltage.? The mean voltage for most common tubes is 6.3 volts with a voltage tolerance of +/- 10%.? Best performance is at 6.3 volts, longest life is at a lower heater voltage but at the price of lower cathode emission, shorter life is at a higher heater voltage which will have higher cathode emission.? For receiving tubes perhaps one will not notice much difference over the +/- 10% heater voltage tolerance.? Power tubes, perhaps over a 100 watts dissipation,? are a different matter and most manufacturers specify a tighter control of heater voltage, usually +/- 5%.? ?This just happens to be the same tolerance as the present 120 volt line voltage convention. Measure your heater voltage.? If it is within a few percent of nominal, then all is OK and you won't have to by any more VARIACs! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Tuesday, March 25, 2025 at 07:44:11 PM CDT, edward schumacher <eddiewa9gqk@...> wrote:
Goes back quite a few years so not that relevant for this discussion. Did have Edison out back then and they verified my readings and said it was due to their tweaking the voltage for other customers around here who are still on the older aerial lines with more voltage drop during peak AC season. Those of us on the buried service saw higher voltage. Since then just run my vintage stuff off Variacs set to 115 to save their aged circuitry. My point was that if VOX circuit voltages are too far off it would affect function. Does not seem that this is the problem for Alan however as he has previously verified voltages. Also seems the mod was done correctly and he has checked the other usual suspects. Considering the tolerances of components back then the circuit should work unless a component has actually gone bad. I built my rig with many used parts and everything worked ok. Will take a closer look at the whole thing later tomorrow after doing errands. 73 ... Ed
On Monday, March 24, 2025 at 11:43:04 PM CDT, Jim Whartenby via groups.io <old_radio@...> wrote:
Ed Out of curiosity, what voltage do you measure on the 240 volt service line, hot to hot at the circuit breaker panel?? You should read close to 240 volts.? Over 250 volts or so is a problem for your electric service provider to solve.? If one hot to neutral reads 130 vac and the other reads 110 vac then you don't have a solid neutral connection at the circuit breaker panel.?? Is your house wired with copper or aluminum wire? Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Monday, March 24, 2025 at 05:16:30 PM CDT, edward schumacher <eddiewa9gqk@...> wrote:
Sorry for so long on the reply but a lot going on here. Went back through all my notes on my HT-37 build (yes, did build one, another story). My only problem with my build occurred with original power supply problems which had increased the voltages to the VOX circuitry. After correcting those problems, the regular VOX worked as planned. I did not have a need to try the breakin mod tho knew someone who I believe did with no problems. Only suspect component I can see is C85, the .22 mfd. If it has gone leaky it would definitely shorten the circuit TC. Be sure your plate voltages meet spec as I have found at least here that Edison is closer to 130 which definitely raise transformer supplies. Hope this helps, let me know. 73 ... Ed, WA9GQK
On Thursday, March 20, 2025 at 07:05:14 PM CDT, Alan via groups.io <alancgut@...> wrote:
Hi, ? I recently did the modification for break-in keying as shown in the Hallicrafters Information Bulletin. ? I used a separate 10M pot and mounted it in the 3/8” empty hole in the back of the chassis. I installed the 4.7M fixed resistor in series and I did remove the .005mf cap from pin #8 of SO8. ? The break-in function works as advertised - counterclockwise for shorter delays. ? However, I do have one issue in that the break-in function is always on. I can not return to normal manual CW operation by turning the pot maximum clockwise as stated. ? My 10M pot actually measured 8.6M so I tried going up to a 6.8M fixed resistor and that didn’t fix the issue. I also tried a 10M fixed resistor and still had the same issue. ? I also tried substituting the V14A VOX diode 6AL5 with 3 other spares that I had here and still had the issue. ? The copy of the bulletin that I have here has a sketch that shows someone using a fixed 22M resistor in place of the normal components resulting in a 2 second delay. I find that interesting in that 22M resistance is certainly beyond the factory’s full clockwise “return to normal manual CW operation” resistance. ? Has anyone here successfully performed this modification and had if perform as described in the bulletin? Maybe I’m missing something, so I thought I’d ask here. ? Regards, Alan, W9CG |
don Root
waltcates
Jim Whartenby