Re: T-4XC Sideband adjustments?
Carrier oscillator is on freq. Sorry but I still dont?know where C-6 is. Is it the big silver looking thing with a slot for a screw driver?or the taller looking thing against the back of the chassis?with the slug sticking out of it?
On Thu, Jan 2, 2025 at 4:41?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Check that your carrier oscillator is at 5645 kHz.? C6 is the ceramic trimmer on top of the chassis, right-rear corner area.
If your CO is on-frequency, you could have a bad filter.? Rare, but it happens.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Thursday, January 2nd, 2025 at 5:09 PM, Ed KG5UN via <maikranze= [email protected]> wrote:
My T-4XC sounds decent on LSB but very tinny and pinched on USB. How do I adjust this? I saw a reference to adjusting C-6 but I can not find a C-6. Where is it?
Thanks, Ed KG5UN
|
Re: T-4XC has a "condition"
OK guys,
?
Here is an observation. I just cleaned the power connection and decided to check the bias again. All knobs turned to ¡°0¡±. Now, on the RF tune I see a ¡°0¡± in the 10 meter section.
At this point I can get the bias to the tick mark. Now I see another ¡°0¡± in the 160 meter range. The lowest bias setting here is .3 amps
?
With the bias set now the tune procedure is closer to what I see on videos and I get a grid dip. But for normal operation all knobs are fully CW.
?
Dean
?
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From: [email protected] <[email protected]>
On Behalf Of VE7PS via groups.io
Sent: Thursday, January 2, 2025 1:06 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] T-4XC has a "condition"
?
Barry...indeed, check for correct idling current with zero
drive. Adjust it using the bias control on the AC-4 power supply.? You are aiming for about 70 mA (the "tick mark").
Also.....practice tuning up into a known good 50 Ohm load rated at 150w or better with known good cables first.?
Dump the "tuner" for now.? I would put a wattmeter inline to the 50 ohm load if you have one,?rather than trying to use the internal relative output meter.? That way there are fewer buttons to "mess" with until you are comfortable with the tune-up process.
And if you are pinning the ammeter...STOP right away, as something is wrong!? Back off the drive and try again.
?
How have you set your bias. That¡¯s the first step. Pinned to the right is not a condition you want to be in for long so I would suggest not tuning up until you figure it out.? I would verify
that you have appropriate and steady bias current first.
On Thursday, January 2, 2025 at 10:01:40 AM CST, Dean N2TNN via
<n2tnn=[email protected]> wrote:
I have a T-4XC in great condition but is not acting normal. It puts out 110 watts, sounds great on CW and cooperates with my straight key. Unknown about the
SSB side because I never used it.
This is difficult to express because I don't really know what I am talking about so here goes. Tuning the rig on different bands takes forever to get it right.
I have watched videos and it looks easy. I follow the instructions in the manual and it never is the same.
All controls are set CCW. I then turn up the gain control slowly, maybe 1/4 the way and the needle pins to the right. Once it is pinned I can never get it to
dip when I adjust the plate knob.
So what I do next is to fool with the controls to get max power out with the lowest SWR on the tuner. With the load knob adjusted for output the needle is still
pinned. When I push it in the needle moves down to about .300
Also, after tuning up with the "tune" setting I go to CW and when I key down I have to fine tune all the settings again.
I really like this rig and want to use it but something is not right. Any suggestions?
|
Re: Replacing T4XC Finals?
Film resistors will work fine. Use the same coils.
The final tubes should be 6JB6's
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Thursday, January 2nd, 2025 at 3:30 PM, Jay W6CJ via groups.io <lastradioman@...> wrote:
I looked into the PA I damaged when a faulty key put the radio in transmit: - One of the parasitic choke leads popped out of the resistor.
- One of the 1-watt cathode resistors is cracked and both read higher than 15 ohms.
- No more than 75mA when tuning.
I'm thinking of replacing the 6GE5s; both cathode resistors with 2-watt film resistors; both parasitic chokes; possibly replacing the 12BY7 driver tube.
Appreciate any expert advice on where else to check and what else to replace.
Thanks & 73 Jay W6CJ
|
Re: T-4XC Sideband adjustments?
Check that your carrier oscillator is at 5645 kHz.? C6 is the ceramic trimmer on top of the chassis, right-rear corner area.
If your CO is on-frequency, you could have a bad filter.? Rare, but it happens.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Thursday, January 2nd, 2025 at 5:09 PM, Ed KG5UN via groups.io <maikranze@...> wrote:
My T-4XC sounds decent on LSB but very tinny and pinched on USB. How do I adjust this? I saw a reference to adjusting C-6 but I can not find a C-6. Where is it?
Thanks, Ed KG5UN
|
My TR7A still has the annoying feature of not going to no signal.
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Thursday, January 2nd, 2025 at 4:48 PM, Gary Follett via groups.io <xntrick1948@...> wrote:
Later TR7¡¯s did not suffer this problem. It seems the pot was changed to one which got to zero ohms before the click.?
Gary
W0DVN On Jan 2, 2025, at 3:44?PM, Rob Sherwood via groups.io <rob@...> wrote:
The R-4C has the same problem. It may go clear back to my original R-4. ?Rob, NC0B-----Original Message-----From:?[email protected]?[mailto:[email protected]] On Behalf Of jerry-KF6VBSent: Thursday, January 02, 2025 11:15 AMTo:?[email protected]Cc: Jim Shorney via?Subject: [DRAKE-RADIO] TR7 AudioOne minor audio annoyance with the TR7 - the volume control doesn't go?all the way to zero.Instead of a tradition voltage divider pot, they do something with the?AGC. ?So to getthe thing to quiet down, I also turn down the RF gain.?????????????????- Jerry, KF6VBOn 2025-01-01 08:06, Jim Shorney via groups.io wrote:FWIW the TR7 uses an LM380. It works pretty well.
On Wed, 1 Jan 2025 10:45:24 -0500
"Mike Bryce via groups.io" <prosolar@...> wrote:
FYI¡ I designed an audio amp board for the R4C that used a LM380.?
Worked great and had plenty of humph to drive the MS4 speaker to room?
filling volume
--
73
-Jim
NU0C
|
Re: Replacing T4XC Finals?
Peter, Oops... I meant 6JB6A's.?? The NOS 6JB6A tubes I see for sale are never listed as "matched pair".... is that going to be a problem? Thanks for the screen resistor advice. 73 Jay W6CJ
Jay:
Couple of things....
Suspect you made an error about the final tubes.? 6GE5's wouldn't fit as they are 12 pin tubes, with the Plate on pin 7 instead of plate cap like the original tube, a 6JB6.? Perhaps you meant 6GJ5?? I believe some have used those in the T4X(any) transmitters.
It's not unusual to see the original cathode resistors up around 17-18 ohms by the time, and they still work fine, but seeing as you will be replacing the cracked one?I would do both for sure.? My "change 'em out" threshold?is usually about 17.2 ohms.
Check the screen resistors while you are in there as well. Again, common to see the original 68 ohm resistors drifted up around 75 ohms or thereabouts.? Higher than that and they get swapped out for new ones.
Good luck.
73 Peter VE7PS
I looked into the PA I damaged when a faulty key put the radio in transmit: - One of the parasitic choke leads popped out of the resistor.
- One of the 1-watt cathode resistors is cracked and both read higher than 15 ohms.
- No more than 75mA when tuning.
I'm thinking of replacing the 6GE5s; both cathode resistors with 2-watt film resistors; both parasitic chokes; possibly replacing the 12BY7 driver tube.
Appreciate any expert advice on where else to check and what else to replace.
Thanks & 73 Jay W6CJ
|
T-4XC Sideband adjustments?
My T-4XC sounds decent on LSB but very?tinny and pinched on USB.? How do I adjust this? I saw a reference to adjusting C-6 but I can not find a C-6. Where is it??
Thanks, Ed KG5UN
|
I don't actually know but suspect they are the same. Pillow stuffing would work OK and is likely cheaper. Anything sold for audio seems to become expensive.
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On 1/2/2025 1:56 PM, Stan Gammons via groups.io wrote: I've wondered if the Acousta-Stuf? Polyfil is the same as the Poly-Fil pillow stuffing one can buy at Walmart?
73
Stan
KM4HQE
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
I've wondered if the Acousta-Stuf? Polyfil is the same as the
Poly-Fil pillow stuffing one can buy at Walmart?
73
Stan
KM4HQE
On 1/2/25 13:52, Joe - W7RKN via
groups.io wrote:
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Yup¡One
and the same, albeit a wee (sic)
bit cheaper at your store
Joe
¨C W7RKN
?
?
Is
this the same product?
|
Rob ¡ª I read somewhere that the last version of the SE-3, with the addition of the "AR" switch on the front panel, involved only the addition of the switch and a 100k resistor.? Can you please confirm that's correct and if so, explain where the 100k resistor
is connected?? ?
Thanks, and happy new year!
Regards,
Art Delibert, KB3FJO
|
Later TR7¡¯s did not suffer this problem. It seems the pot was changed to one which got to zero ohms before the click.?
Gary
W0DVN
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On Jan 2, 2025, at 3:44?PM, Rob Sherwood via groups.io <rob@...> wrote:
The R-4C has the same problem. It may go clear back to my original R-4. ?Rob, NC0B-----Original Message-----From:?[email protected]?[mailto:[email protected]] On Behalf Of jerry-KF6VBSent: Thursday, January 02, 2025 11:15 AMTo:?[email protected]Cc: Jim Shorney via?Subject: [DRAKE-RADIO] TR7 AudioOne minor audio annoyance with the TR7 - the volume control doesn't go?all the way to zero.Instead of a tradition voltage divider pot, they do something with the?AGC. ?So to getthe thing to quiet down, I also turn down the RF gain.?????????????????- Jerry, KF6VBOn 2025-01-01 08:06, Jim Shorney via groups.io wrote:FWIW the TR7 uses an LM380. It works pretty well.
On Wed, 1 Jan 2025 10:45:24 -0500
"Mike Bryce via groups.io" <prosolar@...> wrote:
FYI¡ I designed an audio amp board for the R4C that used a LM380.?
Worked great and had plenty of humph to drive the MS4 speaker to room?
filling volume
--
73
-Jim
NU0C
|
Re: Replacing T4XC Finals?
Jay:
Couple of things....
Suspect you made an error about the final tubes.? 6GE5's wouldn't fit as they are 12 pin tubes, with the Plate on pin 7 instead of plate cap like the original tube, a 6JB6.? Perhaps you meant 6GJ5?? I believe some have used those in the T4X(any) transmitters.
It's not unusual to see the original cathode resistors up around 17-18 ohms by the time, and they still work fine, but seeing as you will be replacing the cracked one?I would do both for sure.? My "change 'em out" threshold?is usually about 17.2 ohms.
Check the screen resistors while you are in there as well. Again, common to see the original 68 ohm resistors drifted up around 75 ohms or thereabouts.? Higher than that and they get swapped out for new ones.
Good luck.
73 Peter VE7PS
I looked into the PA I damaged when a faulty key put the radio in transmit: - One of the parasitic choke leads popped out of the resistor.
- One of the 1-watt cathode resistors is cracked and both read higher than 15 ohms.
- No more than 75mA when tuning.
I'm thinking of replacing the 6GE5s; both cathode resistors with 2-watt film resistors; both parasitic chokes; possibly replacing the 12BY7 driver tube.
Appreciate any expert advice on where else to check and what else to replace.
Thanks & 73 Jay W6CJ
|
The R-4C has the same problem. It may go clear back to my original R-4. Rob, NC0B
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of jerry-KF6VB Sent: Thursday, January 02, 2025 11:15 AM To: [email protected]Cc: Jim Shorney via groups.io Subject: [DRAKE-RADIO] TR7 Audio One minor audio annoyance with the TR7 - the volume control doesn't go all the way to zero. Instead of a tradition voltage divider pot, they do something with the AGC. So to get the thing to quiet down, I also turn down the RF gain. - Jerry, KF6VB On 2025-01-01 08:06, Jim Shorney via groups.io wrote: FWIW the TR7 uses an LM380. It works pretty well.
On Wed, 1 Jan 2025 10:45:24 -0500
"Mike Bryce via groups.io" <prosolar@...> wrote:
FYI¡ I designed an audio amp board for the R4C that used a LM380.
Worked great and had plenty of humph to drive the MS4 speaker to room
filling volume
--
73
-Jim
NU0C
|
Dave, I shipped an R4C (with PTO and other issues) to WB4HFN, who reported the NB was not repairable - parts availability.
Before shipping the R4C with the NB installed, I tried alignment from the R4C manual and not all of the 4NB adjustments were responsive.
Thanks & 73, Jay
Jay, I just took a look at the schematic and didn't see anything that would currently be unavailable except maybe the coils and possibly the socket for the blanker. What is specifically wrong with it? Is it physical damage or electrically not functioning?
?
Dave
|
Small lamp reference for Drake L7
Hello,
?
I am? looking for the part reference for the very small lamps used to display the buttons pushed state (Ep, Ig, STBY, OPR, ...).
?
Thanks you.
|
Re: T-4XC has a "condition"
Peter,
?
Thanks? for the reply. I always use an appropriate dummy load to initiate a tuning process. Once I establish max output I switch over to the antenna and re-tune and adjust.
The output is monitored on a cross needle power/ swr meter.
?
I also just adjusted the bias right on the tick mark.
?
I am going to check the connectors and deoxit to be sure.
?
73, Dean
?
?
?
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From: [email protected] <[email protected]>
On Behalf Of VE7PS via groups.io
Sent: Thursday, January 2, 2025 1:06 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] T-4XC has a "condition"
?
Barry...indeed, check for correct idling current with zero
drive. Adjust it using the bias control on the AC-4 power supply.? You are aiming for about 70 mA (the "tick mark").
Also.....practice tuning up into a known good 50 Ohm load rated at 150w or better with known good cables first.?
Dump the "tuner" for now.? I would put a wattmeter inline to the 50 ohm load if you have one,?rather than trying to use the internal relative output meter.? That way there are fewer buttons to "mess" with until you are comfortable with the tune-up process.
And if you are pinning the ammeter...STOP right away, as something is wrong!? Back off the drive and try again.
?
How have you set your bias. That¡¯s the first step. Pinned to the right is not a condition you want to be in for long so I would suggest not tuning up until you figure it out.? I would verify
that you have appropriate and steady bias current first.
On Thursday, January 2, 2025 at 10:01:40 AM CST, Dean N2TNN via
<n2tnn=[email protected]> wrote:
I have a T-4XC in great condition but is not acting normal. It puts out 110 watts, sounds great on CW and cooperates with my straight key. Unknown about the
SSB side because I never used it.
This is difficult to express because I don't really know what I am talking about so here goes. Tuning the rig on different bands takes forever to get it right.
I have watched videos and it looks easy. I follow the instructions in the manual and it never is the same.
All controls are set CCW. I then turn up the gain control slowly, maybe 1/4 the way and the needle pins to the right. Once it is pinned I can never get it to
dip when I adjust the plate knob.
So what I do next is to fool with the controls to get max power out with the lowest SWR on the tuner. With the load knob adjusted for output the needle is still
pinned. When I push it in the needle moves down to about .300
Also, after tuning up with the "tune" setting I go to CW and when I key down I have to fine tune all the settings again.
I really like this rig and want to use it but something is not right. Any suggestions?
|
Jay, I just took a look at the schematic and didn't see anything that would currently be unavailable except maybe the coils and possibly the socket for the blanker. What is specifically wrong with it? Is it physical damage or electrically not functioning?
?
Dave
|
I looked into the PA I damaged when a faulty key put the radio in transmit: - One of the parasitic choke leads popped out of the resistor.
- One of the 1-watt cathode resistors is cracked and both read higher than 15 ohms.
- No more than 75mA when tuning.
I'm thinking of replacing the 6GE5s; both cathode resistors with 2-watt film resistors; both parasitic chokes; possibly replacing the 12BY7 driver tube.
Appreciate any expert advice on where else to check and what else to replace.
Thanks & 73 Jay W6CJ
|
Looks like reasonable stuff. Will have the advantage over fiberglas that it won't get into your fingers. Fiberlas should be handled with fairly heavy gloves and a dust mask. Most hardware stores have it. I usually use the pink colored stuff for speaker boxes.
Small boxes can be filled with it but large boxes just need to be lined (to maybe two inches thick) to reduce internal reflections and resulting resonances.
BTW, speaker cabinet walls should be very stiff. Don't use particle board, which is heavy but not stiff, high quality plywood is superior. For large cabinets it should be well-braced with the braces at odd spacing so as to break up the surfaces to avoid re-inforcing resonances.
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On 1/2/2025 11:22 AM, n4buq wrote: Is this the same product?
quantity=1 < Bag-260-317?quantity=1>
Barry - N4BUQ
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
I have commented in this and other lists about the speakers sold for communication receivers. I won't repeat everything here. The technology to make a better speaker is not new in any way and can be quite simple. The receiver does not need a high fidelity speaker and one would be a mistake. The range of interest is pretty limited. However, what does matter is the resonances caused by the small open-back box, as you point out. If you mount a "50c" speaker in a decent box you will be amazed at how much better it sounds. For a small speaker, like the one in the MS-4, perhaps half a cubic foot of volume is enough. Easy to make from a minimum of 1/4" plywood. Fill with sound absorbent, insulating fiberglas will do quite nicely. Does not need a port. These small speakers usually have reasonably good response up through the speech range and don't need a lot of low response. Get rid of the resonances caused by the too small enclosure and the mechanical resonances of the un-damped cabinet material.
Note that the audio amplifiers in vacuum tube receivers usually have starved transformers and are marginal in power. A simple pentode power amp usually has a substantial amount of intermodulation distortion as well as harmonic distortion. The I.M. is usually a property of the tube itself, some are better than others. Negative feedback will reduce both kinds of distortion but at the price of needing increased gain somewhere to compensate for the feedback. I can think of only a couple of single ended pentode amps that employed it (RCA AR-88 is an example).
While the audio frequency range and dynamic range of communication receivers is not great the distortion at even fairly low levels, well under a watt, are significant. The effect on both phone and CW are very noticeable. On CW the effect is to magnify the effect of noise and interference. If one connects a high quality amp to the detector output and compares it to the normal output you will hear a distinctive difference, not too subtle. Some old receivers, such as the old Super-Pro and SX-28, had push pull amps which at least reduced the harmonic distortion (don't do anything for I.M.) and the difference in sound between those and the common single-ended amps is very noticeable.
At least one can improve the speaker cabinet rather cheaply.
I certainly agree about the MS-4 cabinet with a power supply taking up almost all the interior volume. Bad for sound but practical and economical, so it was done. The idea that audio quality does not matter in communications is an easy mistake to make, narrow band and does distortion count (you bet it does). A better speaker in a better enclosure will make a difference but just improving the enclosure will surprise you.
I will also point out that even in broadcast receivers, where audio quality was a sales point, the usual arrangement was an open back cabinet with, perhaps, some peaking at around 90Hz to give the illusion of bass.
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On 1/2/2025 7:41 AM, Paul Christensen via groups.io wrote: >¡¯Bob Heil got that part right.? "It's no more than a 50 cent
speaker....in a $50.00? box".¡¯
I don¡¯t think the issue is so much the MS4 speaker cone or magnet. There¡¯s essentially no baffle distance at even moderately low frequencies between the front and back of the cone.? ?That means the forward cone wave short circuits the back wave at those frequencies. And by moderate, I don¡¯t mean Hi-Fi in any way; that requires even more baffle distance or a fully enclosed ¡°infinite baffle.¡±
I¡¯ve closed the back of mine with cardboard and that helps to create a fuller sound from the MS4.? Back in the day, manufacturers that offered speakers as accessories to the main product line put no effort into understanding the effect of baffling.
Paul, W9AC
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
|
Ed KG5UN
Jay W6CJ
Rob Sherwood