Re: Problem with carrier balance pot on T-4XC
The carrier null is so sharp it has to be a multi turn pot. ?Rob, NC0B
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On Mar 28, 2023, at 1:02 PM, Bill Leonard N0CU <billincolo73@...> wrote:
?When I initially checked the carrier balance awhile back it looked like this pot (R21) was set correctly. Today, I attempted to do the filter match alignment (Sec 5.9 in the instruction manual). The instructions call out rotating this pot to
max CCW. However, the shaft continuously rotates with no mechanical stop. I then noticed that the resistance value did not change as the shaft was rotated. I disassembled the pot to see what was wrong. The problem seems to be that the bearings don't rotate
when the shaft rotates, and since the armature is connected to the shaft via the bearings, the resistance does not change. I have never seen a pot like this and wonder what it is about this circuit that required such an unusual pot? I assume that the preload
needed to turn the bearings no longer exists, but I don't see any way to adjust that. Am I missing something? Can I just replace this pot with a standard 200-ohm pot (without the bearings)?
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Bill N0CU
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Problem with carrier balance pot on T-4XC
When I initially checked the carrier balance awhile back it looked like this pot (R21) was set correctly. Today, I attempted to do the filter match alignment (Sec 5.9 in the instruction manual). The instructions call out rotating this pot to max CCW. However, the shaft continuously rotates with no mechanical stop. I then noticed that the resistance value did not change as the shaft was rotated. I disassembled the pot to see what was wrong. The problem seems to be that the bearings don't rotate when the shaft rotates, and since the armature is connected to the shaft via the bearings, the resistance does not change. I have never seen a pot like this and wonder what it is about this circuit that required such an unusual pot? I assume that the preload needed to turn the bearings no longer exists, but I don't see any way to adjust that. Am I missing something? Can I just replace this pot with a standard 200-ohm pot (without the bearings)?
--
Bill N0CU
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Yes. It was installed in a L7 amplifier to prevent it from being
driven on 10-11 meters.
Not very useful I would say.... Most get tossed in the trash.. Which
they should be.
73, Jim W7RY
On 3/28/2023 10:13 AM, Jim VE7RF wrote:
What was it used for...to inhibit? amplifying > 23 mhz ???
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Thanks and 73, Jim W7RY
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Gregg,
If you are going to use with the T4XC, align it with it connected to the transmitter. The injection and antenna cables need to be drake spec cables. That does make a big difference overall. My R4C hears better than my Icom 7300...significantly for in the mud DX. MY R4C is the go getter for weak signal work after being fully aligned.
On Tuesday, March 28, 2023 at 12:06:44 PM EDT, Gregg Lebovitz <gregglebovitz@...> wrote:
Hi Steve,
I have a pretty old, but original inj cable. Do the characteristics change over time? I have been aligning without the connections.
thanks,
gregg
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Thanks - I do also have a Shure 450 so I may use it instead and save the D-104 for another project.
73's
Don W.
KD4APP
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Probably thousands of hams have used this mic with this transceiver.? The other popular mic used is/was the Shure 444!
Lee, w0vt
On 3/28/2023 9:55 AM, Don Woodward - KD4APP wrote:
I am restoring a TR-3 and have already restored the AC-3 and purchased a nice MS-4 - I also purchased a D-104 microphone at a local hamfest recently and would like to use it with the TR-3 - has anyone used this mic with a TR-3 successfully?
Thanks in advance and 73's,
Don W.
KD4APP
|
I bought a L7 back then new and then converted it to be an export
model.? You had to change one input silver mica, re-tune it,
remove a set screw so the band switch would move to the 10 meter
position and then remove the filter which was on a PC board along
with it's attached input and out put coaxial cables.? You then put
in a new longer piece of coax connecting the amp input SO-239 to
the input of the amplifier.? Your amp was now an export model
without the 10 meter label on the band switch.
Lee, w0vt
On 3/28/2023 10:37 AM, Steve Wedge,
W1ES/4 via groups.io wrote:
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I
was wondering the same thing, Peter.
The
parts may be of some use in other applications.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure
email.
------- Original Message -------
On Tuesday, March 28th, 2023 at 11:32 AM, VE7PS
<ve7ps@...> wrote:
Jim:
You won't find that low pass filter board in an
"Export" (like Canada) model. It was installed in the US
models to inhibit 10m operation in a fruitless attempt by
the FCC to stop CB-ers from using ham amps back in the
late '70's and 80's. That's why on the US amps they do not
have 10m marked on the front panel. You could just short
the filter out or pull it completely and connect the
jumper.
Not sure why anyone would want to buy one?
73
Peter
VE7PS
On Tue, Mar 28, 2023 at
8:13?AM Jim VE7RF < jim.thom@...>
wrote:
What was it used for...to inhibit
amplifying > 23 mhz ??
|
Hi Steve,
I have a pretty old, but original inj cable. Do the characteristics change over time? I have been aligning without the connections.
thanks,
gregg
|
I was wondering the same thing, Peter.
The parts may be of some use in other applications.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
------- Original Message -------
On Tuesday, March 28th, 2023 at 11:32 AM, VE7PS <ve7ps@...> wrote:
Jim:
You won't find that low pass filter board in an "Export" (like Canada) model. It was installed in the US models to inhibit 10m operation in a fruitless attempt by the FCC to stop CB-ers from using ham amps back in the late '70's and 80's. That's why on the US amps they do not have 10m marked on the front panel. You could just short the filter out or pull it completely and connect the jumper.
Not sure why anyone would want to buy one?
73 Peter VE7PS
On Tue, Mar 28, 2023 at 8:13?AM Jim VE7RF < jim.thom@...> wrote: What was it used for...to inhibit amplifying > 23 mhz ??
|
Thousands have used the D-104 with all manner of Drake tube gear.? Check to see whether or not the mic has a built-in amp, as that will be a factor in how you set it up.
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
------- Original Message -------
On Tuesday, March 28th, 2023 at 10:58 AM, Leland L. Bahr <w5drc@...> wrote:
Probably thousands of hams have used this mic with this
transceiver. The other popular mic used is/was the Shure 444!
Lee, w0vt
On 3/28/2023 9:55 AM, Don Woodward -
KD4APP wrote:
I am restoring a TR-3 and have already restored the AC-3 and
purchased a nice MS-4 - I also purchased a D-104 microphone at a
local hamfest recently and would like to use it with the TR-3 -
has anyone used this mic with a TR-3 successfully?
Thanks in advance and 73's,
Don W.
KD4APP
|
Jim:
You won't find that low pass filter board in an "Export" (like Canada) model.? It was installed in the US models to inhibit 10m operation in a fruitless attempt?by the FCC to stop CB-ers from using ham amps back in the late '70's and 80's.? That's why on the US amps they do not have 10m marked on the front panel.? You could just short the filter out or pull it completely?and connect the jumper.
Not sure why anyone would want to buy one?
73 Peter VE7PS
On Tue, Mar 28, 2023 at 8:13?AM Jim VE7RF < jim.thom@...> wrote: What was it used for...to inhibit? amplifying > 23 mhz ???
|
What was it used for...to inhibit? amplifying > 23 mhz ???
|
Probably thousands of hams have used this mic with this
transceiver.? The other popular mic used is/was the Shure 444!
Lee, w0vt
On 3/28/2023 9:55 AM, Don Woodward -
KD4APP wrote:
toggle quoted message
Show quoted text
I am restoring a TR-3 and have already restored the AC-3 and
purchased a nice MS-4 - I also purchased a D-104 microphone at a
local hamfest recently and would like to use it with the TR-3 -
has anyone used this mic with a TR-3 successfully?
Thanks in advance and 73's,
Don W.
KD4APP
|
Arnie,
The front end alignment portion would apply to any of the R-4 line. ?
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On Mar 28, 2023, at 7:24 AM, W8DU_Arnie <mdjdmi@...> wrote:
?Rob:
Would the procedures set forth in that document also be applicable to a R4b / T4xc combo?
Tnc es 73 de Arnie W8DU
|
I am restoring a TR-3 and have already restored the AC-3 and purchased a nice MS-4 - I also purchased a D-104 microphone at a local hamfest recently and would like to use it with the TR-3 - has anyone used this mic with a TR-3 successfully?
Thanks in advance and 73's,
Don W.
KD4APP
|
Arnie,
I have used this method for quite some time, with all lines, and it is definitely? LOT less hassle than swamping the premixer.? The tuned band circuits are pretty much identical across the versions (A,B,C).
Another thing to be aware of is that when aligning the transmitter, the caps are adjusted with no receiver or cables connected.? The INJ cable was designed with a specific capacitance so that it should match when connected together.? Some trouble comes when a substitute cable is used because it throws off the tuning.? If you have a different INJ cable (using coax or a different length), then the transmitter and receiver will need to be aligned when they're connected.
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
------- Original Message -------
On Tuesday, March 28th, 2023 at 9:24 AM, W8DU_Arnie <mdjdmi@...> wrote:
Rob:
Would the procedures set forth in that document also be applicable to a R4b / T4xc combo?
Tnc es 73 de Arnie W8DU
|
The ones at AES look identical to the ones I have seen in some of my Collins knobs.? It may be time to experiment and see if they'd work with the Drake knobs that have no setscrew.? Many times, those screwless knobs get loose due to the spring wearing out.
I'll pull one off my second Collins receiver and try it on my TR-4Cw RIT, as that rig will be visiting the bench soon to look at the Squirrely behaviour on 20m.
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
------- Original Message -------
On Tuesday, March 28th, 2023 at 8:13 AM, John K5MO <johnk5mo@...> wrote:
Man, that's an obscure niche product line.
Great find! John
KNOB SPRINGS
LECTRA Fasteners (Arvada, CO)
Manufacturer of D, D with barbs and double-D inserts used with control knobs
CATALOG
greg, w9gb
chicago
|
Rob:
Would the procedures set forth in that document also be applicable to a R4b / T4xc combo?
Tnc es 73 de Arnie W8DU
|
Man, that's an obscure niche product line.
Great find! John
KNOB SPRINGS
LECTRA Fasteners (Arvada, CO)
Manufacturer of D, D with barbs and double-D inserts used with control knobs
CATALOG
greg, w9gb
chicago
|
KNOB SPRINGS
LECTRA Fasteners (Arvada, CO)
Manufacturer of D, D with barbs and double-D inserts used with control knobs
CATALOG
greg, w9gb
chicago
|
Re: TR7/R7 Extender Boards and Puller
Jim and Stan,
Thank you for the puller information.
Chuck
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Rob Sherwood
Greg W9GB