Re: R-4B troubleshooting, was Cabinet repainting
I got PC mount pots from Mouser not that long ago.?
Let us know how it works out!
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Sat, Mar 2, 2024 at 20:54, Stan Gammons via groups.io < buttercup11421@...> wrote:
On 3/2/24 18:20, Steve Wedge, W1ES/4
via groups.io wrote:
Check
the other resistors in the meter bridge circuit. They can drift
out of tolerance.
Also,
check the no-signal level of the S meter with the AGC off vs AGC
on (with no antenna). I had gassy tubes that were driving me
crazy with getting the meter to cal (and the sensitivity to be
normal). When you adjust the pot for -1.35V with the no-signal
AGC on, it should not change more than 100 mV and preferably
less. The two 12BA6's next to the transformer and the 12BE6 are
susceptible.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Hi Steve,
Thanks for the info. I don't have a lot of 12BA6's or 12BE6's in my
spare tubes collection. Still on the to do list is cleaning the
tube sockets. Hopefully the 1K CTS pots will arrive on Tuesday.
They are the horizontal mount pots. Not a problem to bend the legs
and solder a wire to the center pin. I wish CTS still made the 201
series pots. Will troubleshoot more once I replace the pots and see
how sensitive the radio is.
73
Stan
KM4HQE
|
Re: R-4B troubleshooting, was Cabinet repainting
On 3/2/24 18:20, Steve Wedge, W1ES/4
via groups.io wrote:
Check
the other resistors in the meter bridge circuit.? They can drift
out of tolerance.
Also,
check the no-signal level of the S meter with the AGC off vs AGC
on (with no antenna).? I had gassy tubes that were driving me
crazy with getting the meter to cal (and the sensitivity to be
normal).? When you adjust the pot for -1.35V with the no-signal
AGC on, it should not change more than 100 mV and preferably
less.? The two 12BA6's next to the transformer and the 12BE6 are
susceptible.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Hi Steve,
Thanks for the info.? I don't have a lot of 12BA6's or 12BE6's in my
spare tubes collection.? Still on the to do list is cleaning the
tube sockets.? Hopefully the 1K CTS pots will arrive on Tuesday.?
They are the horizontal mount pots.? Not a problem to bend the legs
and solder a wire to the center pin.? I wish CTS still made the 201
series pots.? Will troubleshoot more once I replace the pots and see
how sensitive the radio is.
73
Stan
KM4HQE
|
Check the other resistors in the meter bridge circuit.? They can drift out of tolerance.
Also, check the no-signal level of the S meter with the AGC off vs AGC on (with no antenna).? I had gassy tubes that were driving me crazy with getting the meter to cal (and the sensitivity to be normal).? When you adjust the pot for -1.35V with the no-signal AGC on, it should not change more than 100 mV and preferably less.? The two 12BA6's next to the transformer and the 12BE6 are susceptible.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Saturday, March 2nd, 2024 at 6:41 PM, Stan Gammons via groups.io <buttercup11421@...> wrote:
On 3/2/24 12:12, Dave Edwards wrote:
They originally painted the Drake cabinets in Miamisburg, and would
re-paint them (LIKE NEW) until only recently.
I've sent many to them over the years.
....Dave
Thanks everyone for the tips on repainting the cabinets. When the
weather is more favorable for painting;I'll work on repainting the
cabinets.
Currently working on the R-4B. It has a bad receiver sensitivity
pot, R87, and a bad S meter sensitivity pot, R40. Waiting on
replacement parts from an Epay seller before continuing to
troubleshoot the receiver. As temp fixes, I soldered 560 ohm
resistors in place of the pots. Sensitivity seems a bit low, but it
receives and the S meter moves.
73
Stan
KM4HQE
|
On 3/2/24 12:12, Dave Edwards wrote:
They originally painted the Drake cabinets in Miamisburg, and would
re-paint them (LIKE NEW) until only recently.
I've sent many to them over the years.
....Dave
Thanks everyone for the tips on repainting the cabinets.??? When the
weather is more favorable for painting;I'll work on repainting the
cabinets.
Currently working on the R-4B.? It has a bad receiver sensitivity
pot, R87,? and a bad S meter sensitivity pot, R40.? Waiting on
replacement parts from an Epay seller before continuing to
troubleshoot the receiver.? As temp fixes, I soldered 560 ohm
resistors in place of the pots.? Sensitivity seems a bit low, but it
receives and the S meter moves.
73
Stan
KM4HQE
|
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
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¡ãC) 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.
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.
|
S/N 18738. I still have the PTO out of the set. It was nice outside here today (18¡ãC) 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.
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.
|
Re: Drake MN7 Tuner Knobs
Bill, so far so good, but I know I don't have the clear scales. What is the knob diameter? I think the ones in the middle drawer might be a match.?  -- 73, Kevin, K8KVN
|
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.
|
They originally painted the Drake cabinets in Miamisburg, and would re-paint them (LIKE NEW) until only recently.
I've sent many to them over the years.
....Dave
toggle quoted message
Show quoted text
On 3/2/24 12:55 PM, jerry-KF6VB wrote: On 2024-03-02 08:32, Dave Edwards wrote:
Sure wish Hartzell was still 'on it' !! *** The airplane propeller people?
??????????????????? - Jerry, KF6VB
|
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.
|
On 2024-03-02 08:32, Dave Edwards wrote: Sure wish Hartzell was still 'on it' !! *** The airplane propeller people? - Jerry, KF6VB
|
Sure wish Hartzell was still 'on it' !!
"Dave,
We can only do the black tex
finish. The 7 series was painted with a coating that is not
available now. Some units did have a vinyl coating.
Sorry we cant get that material.
Dave"
On 3/1/24 10:16 PM, Stan Gammons via
groups.io wrote:
toggle quoted message
Show quoted text
I'm looking to do a little restoration work on a new to me 4 line. T4X,
R-4B and MS4.? I've read Mark, WB0IQK, article on the WB4HFN site about
cabinet repainting.? Problem is I can't seem to find the Krylon primer
or paint at any of the local big box places.? About all I've been able
to find is the Krylon Fusion series that's primer and paint. I have no
idea how well the Krylon 2732 Satin Black matches the original paint.?
Anyone know if the Krylon 2732 will match the original paint?
73
Stan
KM4HQE
|
Re: Drake MN7 Tuner Knobs
The Black Fluted (2 inch skirt) Knobs, without the clear numeric index, are available from several sources.
MAX-GAIN Systems
The numeric index could be fabricated from clear acrylic circle,
and attached to back of the fluted knob. There are three cast locations on back for attachment.
w9gb
|
Stan, I¡¯ve used both the Krylon black satin and the Rustoleum black satin. Both work well.?
If your sets are B period (and there is some overlap with the T-4X) sand the cabinet down, graduating to a very fine (320 is okay). ?You can remove all the paint but I¡¯ve found it not necessary. Spray a couple of thin coats.?
Now take a very small drill bit like a 1/16¡± and either drill out a removable spray nozzle or the nozzle on the can you¡¯re using (it seems that a lot of paints no longer have a removable nozzle). Practice first on a piece of scrap material to see the spatter effect it creates. I usually get about two feet from the cabinet and give it a light spray.?
I¡¯ve had great results using this method. There is an article on Ron¡¯s site that goes over this.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Fri, Mar 1, 2024 at 22:16, Stan Gammons via groups.io < buttercup11421@...> wrote: I'm looking to do a little restoration work on a new to me 4 line. T4X,
R-4B and MS4. I've read Mark, WB0IQK, article on the WB4HFN site about
cabinet repainting. Problem is I can't seem to find the Krylon primer
or paint at any of the local big box places. About all I've been able
to find is the Krylon Fusion series that's primer and paint. I have no
idea how well the Krylon 2732 Satin Black matches the original paint.
Anyone know if the Krylon 2732 will match the original paint?
73
Stan
KM4HQE
|
I have used the Krylon Satin Black on a lot of Drake rigs.? Works great if you don't mind that it is a smooth finish. I strip all the paint off the cabinet, down to bare metal with a rotary sander.? Then spray the metal with Rust Reformer, which will get any rust pits. Then seal that with red primer. And finally two coats of the satin black. Between coats of paint I wet sand it down with 1200 grit. ? Also between coats I let it sit out in the sun? all afternoon .. obviously this is a summer time project. About a month later, after the paint has hardened,? I wet sand all the orange peel off, using a rubbing compound . This is the step that leaves a "factory finish".
On Fri, Mar 1, 2024, 22:16 Stan Gammons via <buttercup11421= [email protected]> wrote: I'm looking to do a little restoration work on a new to me 4 line. T4X,
R-4B and MS4.? I've read Mark, WB0IQK, article on the WB4HFN site about
cabinet repainting.? Problem is I can't seem to find the Krylon primer
or paint at any of the local big box places.? About all I've been able
to find is the Krylon Fusion series that's primer and paint. I have no
idea how well the Krylon 2732 Satin Black matches the original paint.?
Anyone know if the Krylon 2732 will match the original paint?
73
Stan
KM4HQE
|
Re: Another TR7 Journey begins
Regardless, something is jacked up related to the meter circuit. The pointer should rest at zero when power is off. It should never go below zero in normal operation. Look at the front of the radio. You will see two buttons marked FIXED, one RCV and the other XMIT. These are for use with the fixed frequency crystal option provided by the AUX-7 accessory board. You will probably never use them and they should be normally out. If you push one in the PLL will unlock for either receive or transmit, depending on which one you push, because there is no fixed crystal installed for the PLL to lock to. If one of the switches goes intermittent because of non-use it would have the same effect. The usual fix is to exercise the switches until they work again. It is easy to see PLL unlock. The frequency display will track the VCO as it free runs and you will see it drift until it settles somewhere that you don't expect it to be. This is in fact a service check in the alignment section to ensure the VCO is aligned about where it should be. See the first paragraph of section 3-7 of the Alignment Procedure. 73 -Jim NU0C On Fri, 01 Mar 2024 14:03:31 -0800 "Bill NZ0T" <nz0tham@...> wrote: Thanks Jim,
Just to be sure the meter is going full scale left on transmit as in below zero.? My dummy load is a Heathkit HM-2103 old but in great shape.? It is a wattmeter with a big dry dummy load.? But I use an LP-100A for a wattmeter which is very accurate and the old Heath as a dummy load tho the wattmeter in it is usually close to the LP-100A.? I hadn't thought of PLL unlock as I figured that would cause RX to go to and it hasn't.? What is a FIXED switch.
73, Bill NZ0T
-- 73 -Jim NU0C
|
I'm looking to do a little restoration work on a new to me 4 line. T4X,
R-4B and MS4.? I've read Mark, WB0IQK, article on the WB4HFN site about
cabinet repainting.? Problem is I can't seem to find the Krylon primer
or paint at any of the local big box places.? About all I've been able
to find is the Krylon Fusion series that's primer and paint. I have no
idea how well the Krylon 2732 Satin Black matches the original paint.?
Anyone know if the Krylon 2732 will match the original paint?
73
Stan
KM4HQE
|
Re: Drake MN7 Tuner Knobs
Kevin, Here you go, thanks. This is an internet picture. Hope this works. 73 Bill W4WCS 
|
Re: Another TR7 Journey begins
Thanks Jim,
Just to be sure the meter is going full scale left on transmit as in below zero.? My dummy load is a Heathkit HM-2103 old but in great shape.? It is a wattmeter with a big dry dummy load.? But I use an LP-100A for a wattmeter which is very accurate and the old Heath as a dummy load tho the wattmeter in it is usually close to the LP-100A.? I hadn't thought of PLL unlock as I figured that would cause RX to go to and it hasn't.? What is a FIXED switch.
73, Bill NZ0T
|
Re: Another TR7 Journey begins
Not going into transmit mode at all is a sign of PLL unlock. One common cause of this is dirty FIXED switches on the front panel. It could also be an issue with the TX Exciter board or related wiring/connections. Not sure what to think about your wattmeter issue. Time to start following voltages and testing components to find out where the full scale reading is coming from. What are you using for external wattmeter and dummy load? The counter that I use is a Leader LDC823S. Not cheap but not HP level in pricing, although they can sometimes be found for a low price. Sensitive enough for reading low level oscillators, stable and seems to hold cal well. Leader has been somewhat of a sleeper in the test equipment market. Good stuff but not widely known. I also recently scored a B&K 1823A for free (sometimes I get lucky) that looks promising, but I have not had the opportunity to give it a workout yet. It appears to be a re-badged Unisource FC-8xxx variant. It came out of a QA lab so I am assuming it doesn't suck. Other possibilities are surplus Fluke and low-end HP, which I also have but have likewise not tested with Drakes because the Leader has been working out so well. The key points to look for are a stable, accurate reference oscillator and sensitivity good enough to pick up the oscillators in the radio. That pretty much leaves out most of the cheap Chinese eBay fodder, but there could be something suitable there. Of course any counter you get will need to have the calibration checked, which for ham use can be as simple as checking the reference oscillator against WWV's carrier. 73 -Jim NU0C On Fri, 01 Mar 2024 11:43:22 -0800 "Bill NZ0T" <nz0tham@...> wrote: I got the replacement board? yesterday and put it in this morning.? I am able to adjust the 8.05 oscillator to about 5.645 MHz but it moves around a bit? in frequency on the counter.? I listened to it on my K4 the oscillator signal is steady so I've got to find a better counter to do this correctly.? A small squirt of DeOxit Fader on the ALC control seems to have helped but the ALC adjustment is still kind of wonky in that if I adjust it to 140 - 150 watts on 14 MHZ and then go to 289.5 per the service manual I get litle or no output and adjustment of R2227 on the predriver board does nothing.? And the wattmeter calibration also is still not doing anything with adjustment of R2001 on the LPF board having no effect at all.? The meter goes full left on transmit.? And now the rig has stopped transmitting.? By that I mean that it will not go into transmit mode at all in CW or SSB.? Aggghhhh!
I'm open for suggestions for a decent frequency counter that won't cost an arm and a leg.? I plan to read the schematics again but I'm wondering if the TX problem may? be leaky pin diodes that finally died?
73, Bill NZ0T
-- 73 -Jim NU0C
|
Greg W9GB
Jim Shorney
Bill