C Line PTO Bumpiness

I'm still working on this R-4C that keeps throwing new problems at me as I go along.

I had noticed that I could feel a little "bump" as I rotated the main tuning knob and it was serious enough for the bushing to slip.? The rotation was stiff, as well.

First, the stiffness was resolved with recommendations that you can find in the "Smooth and Silky" article on Ron's page.? Some 1000 grit paper, lightly applied, removed some burrs on the brass shaft and cleared up crud from inside the brass busing that goes around the main shaft.? But I still had that bumpiness!? Fearing the worst, I put on my 4-diopter readers and had a closer look.

The rearmost gear was bumping off a very small mass of crud between the teeth of the rear gear of the cluster gear.? Every revolution, you could see the tension arm move when the bump was hit.? A toothbrush cleared out the piece of crud -- which was easy to see with sufficient magnification.

I'm going to head upstairs for lunch now, then put the PTO back into the receiver and see how it goes.? This receiver has other issues that I don't think I can fix due to design.? This R-4C was the early implementation of the 5-filter design but it uses 6HS6's for the mixers.? With just a signal generator or the calibrator, I get faint birdies from the calibrator/generator about 2 kHz away from the main signal.? It's the strangest thing.? I also can't get it to give me S3 with a 1 uV signal but on the air, it sounds like it has all its "marbles".

73,

Steve Wedge, W1ES/4

Time flies like an arrow.? Fruit flies like a banana.

Sent with secure email.

#76397

Steve:

An educated guess knowing about the 5 filter positions and 6JS6's would put the serial # of that R-4C between 18,726 and 21,000.? What is the serial number and does the PTO have any idler gear "levers"?? A pic looking down on the top of the PTO would be helpful, especially if the pilot lamp shroud is still off....but probably too late for that now.

There are some interesting observations about the PTO types used in that serial number range, and some "holes" in the data.? What I have so far suggests Drake was experimenting in that timeframe with metal gears, an idler lever, but with no anti-backlash gears like the late?R-4C.

Yup - ALL the gears need to be nice and clean!

73

Peter

VE7PS

Show quoted text

On Sat, Mar 2, 2024 at 10:09?AM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

I'm still working on this R-4C that keeps throwing new problems at me as I go along.

I had noticed that I could feel a little "bump" as I rotated the main tuning knob and it was serious enough for the bushing to slip.? The rotation was stiff, as well.

First, the stiffness was resolved with recommendations that you can find in the "Smooth and Silky" article on Ron's page.? Some 1000 grit paper, lightly applied, removed some burrs on the brass shaft and cleared up crud from inside the brass busing that goes around the main shaft.? But I still had that bumpiness!? Fearing the worst, I put on my 4-diopter readers and had a closer look.

The rearmost gear was bumping off a very small mass of crud between the teeth of the rear gear of the cluster gear.? Every revolution, you could see the tension arm move when the bump was hit.? A toothbrush cleared out the piece of crud -- which was easy to see with sufficient magnification.

I'm going to head upstairs for lunch now, then put the PTO back into the receiver and see how it goes.? This receiver has other issues that I don't think I can fix due to design.? This R-4C was the early implementation of the 5-filter design but it uses 6HS6's for the mixers.? With just a signal generator or the calibrator, I get faint birdies from the calibrator/generator about 2 kHz away from the main signal.? It's the strangest thing.? I also can't get it to give me S3 with a 1 uV signal but on the air, it sounds like it has all its "marbles".

73,

Steve Wedge, W1ES/4

Time flies like an arrow.? Fruit flies like a banana.

Sent with secure email.

#76399

S/N 18738. I still have the PTO out of the set. It was nice outside here today (18°C) so I finished

Putting the new dashboard into my TR6.?

Top and bottom views…

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from for iOS

Show quoted text

On Sat, Mar 2, 2024 at 14:16, VE7PS <ve7ps@...> wrote:

Steve:

An educated guess knowing about the 5 filter positions and 6JS6's would put the serial # of that R-4C between 18,726 and 21,000. What is the serial number and does the PTO have any idler gear "levers"? A pic looking down on the top of the PTO would be helpful, especially if the pilot lamp shroud is still off....but probably too late for that now.

There are some interesting observations about the PTO types used in that serial number range, and some "holes" in the data. What I have so far suggests Drake was experimenting in that timeframe with metal gears, an idler lever, but with no anti-backlash gears like the late R-4C.

Yup - ALL the gears need to be nice and clean!

73
Peter
VE7PS

On Sat, Mar 2, 2024 at 10:09?AM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:
I'm still working on this R-4C that keeps throwing new problems at me as I go along.

I had noticed that I could feel a little "bump" as I rotated the main tuning knob and it was serious enough for the bushing to slip. The rotation was stiff, as well.

First, the stiffness was resolved with recommendations that you can find in the "Smooth and Silky" article on Ron's page. Some 1000 grit paper, lightly applied, removed some burrs on the brass shaft and cleared up crud from inside the brass busing that goes around the main shaft. But I still had that bumpiness! Fearing the worst, I put on my 4-diopter readers and had a closer look.

The rearmost gear was bumping off a very small mass of crud between the teeth of the rear gear of the cluster gear. Every revolution, you could see the tension arm move when the bump was hit. A toothbrush cleared out the piece of crud -- which was easy to see with sufficient magnification.

I'm going to head upstairs for lunch now, then put the PTO back into the receiver and see how it goes. This receiver has other issues that I don't think I can fix due to design. This R-4C was the early implementation of the 5-filter design but it uses 6HS6's for the mixers. With just a signal generator or the calibrator, I get faint birdies from the calibrator/generator about 2 kHz away from the main signal. It's the strangest thing. I also can't get it to give me S3 with a 1 uV signal but on the air, it sounds like it has all its "marbles".

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with secure email.

#76400

Thanks for sending that Steve.? I now have it entered in my database.? This is the 2nd oldest PTO with the dual idler levers, and all plastic gears I have seen. The oldest is #18,216, which came out even before the electronics change that?occurred?at #18,726. Of course this assumes that the original PTO was in that radio.

At one time, the data I had seemed to indicate that the dual lever, all plastic geared PTO began with the major electronic changes at #21,000 (6EJ7's), but clearly?that is not the case.

Again....thank you.

73

Peter

VE7PS

Show quoted text

On Sat, Mar 2, 2024 at 2:15?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

S/N 18738. I still have the PTO out of the set. It was nice outside here today (18°C) so I finished
Putting the new dashboard into my TR6.?

Top and bottom views…

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from for iOS

On Sat, Mar 2, 2024 at 14:16, VE7PS <ve7ps@...> wrote:

Steve:

An educated guess knowing about the 5 filter positions and 6JS6's would put the serial # of that R-4C between 18,726 and 21,000. What is the serial number and does the PTO have any idler gear "levers"? A pic looking down on the top of the PTO would be helpful, especially if the pilot lamp shroud is still off....but probably too late for that now.

There are some interesting observations about the PTO types used in that serial number range, and some "holes" in the data. What I have so far suggests Drake was experimenting in that timeframe with metal gears, an idler lever, but with no anti-backlash gears like the late R-4C.

Yup - ALL the gears need to be nice and clean!

73
Peter
VE7PS

On Sat, Mar 2, 2024 at 10:09?AM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:
I'm still working on this R-4C that keeps throwing new problems at me as I go along.

I had noticed that I could feel a little "bump" as I rotated the main tuning knob and it was serious enough for the bushing to slip. The rotation was stiff, as well.

First, the stiffness was resolved with recommendations that you can find in the "Smooth and Silky" article on Ron's page. Some 1000 grit paper, lightly applied, removed some burrs on the brass shaft and cleared up crud from inside the brass busing that goes around the main shaft. But I still had that bumpiness! Fearing the worst, I put on my 4-diopter readers and had a closer look.

The rearmost gear was bumping off a very small mass of crud between the teeth of the rear gear of the cluster gear. Every revolution, you could see the tension arm move when the bump was hit. A toothbrush cleared out the piece of crud -- which was easy to see with sufficient magnification.

I'm going to head upstairs for lunch now, then put the PTO back into the receiver and see how it goes. This receiver has other issues that I don't think I can fix due to design. This R-4C was the early implementation of the 5-filter design but it uses 6HS6's for the mixers. With just a signal generator or the calibrator, I get faint birdies from the calibrator/generator about 2 kHz away from the main signal. It's the strangest thing. I also can't get it to give me S3 with a 1 uV signal but on the air, it sounds like it has all its "marbles".

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with secure email.

开云体育

C Line PTO Bumpiness