Re: L4B Vernier Drive - different question
My L-4B tuning vernier drive fix will appear in the March issue of QST in the Hints and Hacks column. ?As an aside a source of vernier drives and surprisingly some red pointers for two different size drives can be purchased from?.
73 - Dino KL?S
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Re: T-4XC generating unwanted tuned signal in R-4C
Update:? I connected my other T-4XC to the setup and discovered that pin 7 of Mixer v3? of my other rig is 240 Volts in stand-by (RX) mode.......? I swapped the 6AU6 but to no evail.? WIll continue to look why the Mixer's cathode has such low voltage as I am getting convinced this is the reason why it is still mixing the carrier oscilator and injection frequencies while in stand-by (RX) mode.
Will keep you posted?
73 de PA9Z
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Re: T-4XC generating unwanted tuned signal in R-4C
Is perhaps VOX being tripped ? Is there? bias current showing on the transmitter meter?
Hopefully some smart people will be along soon with better questions :-) John
Hi John
Thanks for thinking with me. Yes, I have another one, a Sure, but that is shortened when the PTT button is not pushed. Then no signal in SSB is generated, however when switching to AM of course generate an (unmodulated) AM carrier is generated.
Rob
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Re: T-4XC generating unwanted tuned signal in R-4C
Hi John
Thanks for thinking with me. Yes, I have another one, a Sure, but that is shortened when the PTT button is not pushed. Then no signal in SSB is generated, however when switching to AM of course generate an (unmodulated) AM carrier is generated.
Rob
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Re: T-4XC generating unwanted tuned signal in R-4C
Do you have another microphone to try with this setup?
John
Dear all
A small addition: the unwanted signal does not appear when the MODE is switched to CW (of course again in stand-by (RX) mode) of the T-4XC
73 Rob PA9Z
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Re: T-4XC generating unwanted tuned signal in R-4C
Dear all
A small addition: the unwanted signal does not appear when the MODE is switched to CW (of course again in stand-by (RX) mode) of the T-4XC
73 Rob PA9Z
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T-4XC generating unwanted tuned signal in R-4C
Dear all,
A happy new year to everybody on this marvelous group!
For weeks I am trying to tackle a weird problem in a recently acquired T-4XC.? In stand-by (or RX) mode, with the TRANCEIVE switch in either XMTR or RCVR position, the rig generates a low RF signal (modulated by the connected microphone!) on a freqency set by the respectve PTO.? The connected R-4C then receives this signal via its antenna input which overrides the weaker signals received via the antenna. This signal is quite strong, S9+.
When tuning the respective PTO, that RF signal moves along, hence is received anywhere on the band....... This happens in both AM and SSB mode.
So, in stand-ny (RX) mode, all oscillators and mixers seem to be opartional, hence f(RF) = f(xtal) - f(PTO) - f(carrier osc) generating? signal that is being picked up by the R-4C.
Question 1: Which of the oscillators, pre-mixer and mixer are switched off in the?stand-by (RX) mode?
Question 2: What is the voltage of the cathode (pin 7) of the Mixer V3 (6AU6) in?stand-by (RX) mode? Mine is 10 volts, rather low, suspecting that it is thertefore still operational (mixing) hence generating the unwanted f(RF) product.?
Any thoughts?
73 de Rob PA9Z
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Hi Tim
So the humming comes from the speaker?? Is it a 60 Hz AC hum, you recon??
KR Rob
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Hi Rob and thanks for the response. Yes the T-4XB is connected to a R-4B receiver. The hum is present with the receiver turned on or off. I tried as you suggested unplugging each cable one at a time with no difference in the problem. Any other suggestions are appreciated.
Tim
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Yes, but the subject was the neons. Those are the ones that are soldered. Also, I pointed Stan to exact replacements on Mouser. They are still available under the original OEM part number. 73 -Jim NU0C On Tue, 02 Jan 2024 06:30:20 -0800 "Mark - WB0IQK" <mgilger@...> wrote: It uses two #1850 incandescent lamps.
Mark, WB0IQK
-- 73 -Jim NU0C
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Re: TR7 Getting ready to sell. But have to deal with the dastardly DR7 board again. I thought.
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It uses two #1850 incandescent lamps.?
Mark, WB0IQK
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Re: For sale: 1A receiver
Interesting. I have serial 336, I believe, and it doesn¡¯t have the calibrator. I wonder if the rest of yours agrees with the commonly distributed schematic.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Mon, Jan 1, 2024 at 22:40, Paul Ellis via groups.io < paulz67@...> wrote: I didn't think I'd ever sell this, but a new-to-me shiny (Collins-flavored) object entered my shack last week, so something has to leave, and so...
For sale: 1A receiver, S/N 368. 80-10 meters, + WWV.
I've owned this a couple years, pairing it with a Hallicrafters HT-37. Good condition, but certainly not perfect. Powers up straight away, stable VFO. S-meter in-op; I suspect that it's the S-meter zero pot, but never dove into it any further. 12X4 rectifier tube replaced with two diodes under chassis, done by a prior owner.? In any case, it receives well and sounds good from the internal speaker. Copper inside is average to good; some typical tarnishing, but tube labels, etc. are still legible. The case has typical wear, some paint chips and scratches, but all there with what appears to be all of the correct screws. See pics.
That said, I'd consider it (like most gear of this vintage), a working project, ready to be used and enjoyed casually, or at a good place for a thorough going-through and tweaking.
Price: $450. I'd strongly prefer local pickup (I'm located in eastern Iowa, just minutes off I-80, in Iowa City), but may be able to meet/deliver in a good chunk of the midwest USA. If you really want it shipped, I can assist with packaging and transport to UPS; shipping is on your dime.
73,
Paul
KA0JQF
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Dear Tim
Interesting problem. Where do you hear this hum? ?In the R-4B speaker? Assuming you are operating the T-4XB as Twins? ?Have you decoupled the connecting cables on by one and monitored any change? Is earthing connected properly?
73 Rob PA9Z
toggle quoted message
Show quoted text
Op 2 jan 2024 om 04:27 heeft Tim Randa <randaranch@...> het volgende geschreven: ?As the title suggests my T-4XB has a hum when keyed up in cw mode. At first I thought it was sidetone and tried a couple of replacement 6EV7 tubes hoping that was an easy fix but it was not. The more I listen it really sounds like a loud hum. The sidetone still sounds fine and is louder than the hum. This does not happen when keyed up in ssb mode. I would appreciate some suggestions from the boards gurus as to where to look. Many years ago I was thinking I tackled this problem before with the hayseed capacitor can but my memory is far past its prime.
Thanks in advance for your time in responding
Tim? K?FL
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Those are neon lamps. 73 -Jim NU0C On Mon, 01 Jan 2024 23:27:07 +0000 "Stan Gammons via groups.io" <buttercup11421@...> wrote: I decided to go ahead and replace the incandescent lamps while I had the amp apart. After 40+ years, they have to be getting tired... Just need to solder the leads to the terminal strip. Looks like tomorrow before I finish this project since I've been watching college football. -- 73 -Jim NU0C
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I didn't think I'd ever sell this, but a new-to-me shiny (Collins-flavored) object entered my shack last week, so something has to leave, and so...
For sale: 1A receiver, S/N 368. 80-10 meters, + WWV.
I've owned this a couple years, pairing it with a Hallicrafters HT-37. Good condition, but certainly not perfect. Powers up straight away, stable VFO. S-meter in-op; I suspect that it's the S-meter zero pot, but never dove into it any further. 12X4 rectifier tube replaced with two diodes under chassis, done by a prior owner.? In any case, it receives well and sounds good from the internal speaker. Copper inside is average to good; some typical tarnishing, but tube labels, etc. are still legible. The case has typical wear, some paint chips and scratches, but all there with what appears to be all of the correct screws. See pics.
That said, I'd consider it (like most gear of this vintage), a working project, ready to be used and enjoyed casually, or at a good place for a thorough going-through and tweaking.
Price: $450. I'd strongly prefer local pickup (I'm located in eastern Iowa, just minutes off I-80, in Iowa City), but may be able to meet/deliver in a good chunk of the midwest USA. If you really want it shipped, I can assist with packaging and transport to UPS; shipping is on your dime.
73,
Paul
KA0JQF
|
As the title suggests my T-4XB has a hum when keyed up in cw mode. At first I thought it was sidetone and tried a couple of replacement 6EV7 tubes hoping that was an easy fix but it was not. The more I listen it really sounds like a loud hum. The sidetone still sounds fine and is louder than the hum. This does not happen when keyed up in ssb mode. I would appreciate some suggestions from the boards gurus as to where to look. Many years ago I was thinking I tackled this problem before with the hayseed capacitor can but my memory is far past its prime.
Thanks in advance for your time in responding
Tim? K?FL
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Re: L4B Vernier Drive - different question
Well the pointer follows the capacitor, not the knob.
73, Jim W7RY
On 1/1/2024 8:03 PM, Evan via groups.io
wrote:
Carol,
All the L4B amps ?I've owned
or serviced had a plate tune vernier drive with red pointer
that is attached to the vernier, not the knob.
73,
Evan, K9SQG
Hello,
I recently acquired an L4B that is in great shape
electronically and cosmetically, I have refurbished it and
installed the Harbach boards in the Amp and PSU.??It
appears to function "as advertised", however I have one
question as my only experience with the L4B is this one.
Do all L4B's have a plate capacitor vernier drive? Mine is
smooth and has full travel however the red pointer moves
at the same rate and in synch with the knob - unlike the
RF tune and preselector on the TX and RX which are
obviously vernier. This question did not occur to me when
I had it on the bench and I don't want to pull the front
cover off on a wild goose chase.
Thanks a lot
Carol
K5TFL
--
Thanks and 73, Jim W7RY
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Re: L4B Vernier Drive - different question
Carol,
All the L4B amps ?I've owned or serviced had a plate tune vernier drive with red pointer that is attached to the vernier, not the knob.
73,
Evan, K9SQG
On Monday, January 1, 2024 at 07:23:47 PM EST, Carol K5TFL <carolsugars@...> wrote:
Hello,
I recently acquired an L4B that is in great shape electronically and cosmetically, I have refurbished it and installed the Harbach boards in the Amp and PSU.??It appears to function "as advertised", however I have one question as my only experience with the L4B is this one.
Do all L4B's have a plate capacitor vernier drive? Mine is smooth and has full travel however the red pointer moves at the same rate and in synch with the knob - unlike the RF tune and preselector on the TX and RX which are obviously vernier. This question did not occur to me when I had it on the bench and I don't want to pull the front cover off on a wild goose chase.
Thanks a lot
Carol
K5TFL
|
L4B Vernier Drive - different question
Hello,
I recently acquired an L4B that is in great shape electronically and cosmetically, I have refurbished it and installed the Harbach boards in the Amp and PSU.??It appears to function "as advertised", however I have one question as my only experience with the L4B is this one.
Do all L4B's have a plate capacitor vernier drive? Mine is smooth and has full travel however the red pointer moves at the same rate and in synch with the knob - unlike the RF tune and preselector on the TX and RX which are obviously vernier. This question did not occur to me when I had it on the bench and I don't want to pull the front cover off on a wild goose chase.
Thanks a lot
Carol
K5TFL
|
Rob PA9Z
Jim Shorney
Bill
