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Re: 6JB6A

 

¿ªÔÆÌåÓý

Yes this tubes was designed for TV sweep circuits, so 6JS6, 6KD6, PL509 etc and fortunately can serve as RF pwr amps.

I'm already retired and after 50 years of license finally I was able to get a functional TR-4C. I never forget the fascination this rig create at a 14 yo boy when he (me) visited a local ham shack back then and this guy literally cloned a TR-4C. He gave me a hand made diagram, chassis drawing etc but It was too much for me. I barely was able to assemble a 6DQ6 choke modulated AM TX.

51 years in the future and the "sound of a Drake receiver" still in the memory. And then I got this one last year. And a month ago a second one with RV-4C, untouched internally, noise blanker on place, only the finals are a bit tired and C145 needed to be restored as some of the power supply elet as well (all originals).

Thanks for the tips.

73
Marcus PY2PLL

Em 27/05/2025 09:22, David via groups.io escreveu:

The tube was first made for TV use
? The shorter envelope was first and all other brands copied that.? ?It was later that the long tube came out.? Note the tube was invented for TV use not drake radio use.? ?I learned of the longer version the hard way when I put new tubes in a TR4.? The plate caps were just over the edge of the cage and shorted out.??
Good luck and hope you stay with the drake line forever.? I have about 35 pieces in varying stages of use.

David Assaf III
W5XU??? VP8RXU

On Tue, May 27, 2025, 6:39 AM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Hi David:

Yes, they're will not be mixed. All from the same brand, but not matched (from RF Parts). Interesting that on RCA tube description they say:? "For Horizontal-Deflection-Amplifier. For use in Drake Equipment.". May be ok on "T4" but not on TR(x)? U$35. But they have GE as well (U$39).

73
Marcus PY2PLL

Em 26/05/2025 14:26, David via escreveu:
I would stay with one brand. Do not mix.? RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU??? VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf


Re: 6JB6A

 

The tube was first made for TV use
? The shorter envelope was first and all other brands copied that.? ?It was later that the long tube came out.? Note the tube was invented for TV use not drake radio use.? ?I learned of the longer version the hard way when I put new tubes in a TR4.? The plate caps were just over the edge of the cage and shorted out.??
Good luck and hope you stay with the drake line forever.? I have about 35 pieces in varying stages of use.

David Assaf III
W5XU??? VP8RXU

On Tue, May 27, 2025, 6:39 AM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Hi David:

Yes, they're will not be mixed. All from the same brand, but not matched (from RF Parts). Interesting that on RCA tube description they say:? "For Horizontal-Deflection-Amplifier. For use in Drake Equipment.". May be ok on "T4" but not on TR(x)? U$35. But they have GE as well (U$39).

73
Marcus PY2PLL

Em 26/05/2025 14:26, David via escreveu:
I would stay with one brand. Do not mix.? RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU??? VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf

Re: 6JB6A

 

¿ªÔÆÌåÓý

Hi Steve;

Yes, will be all the same brand but not a matched trio. But all NOS. I guess GE is a good option too.

73
Marcus PY2PLL

Em 26/05/2025 15:17, Steve Wedge, W1ES/4 via groups.io escreveu:

From my experience, stick to GE or Sylvania.? Do not mix brands unless you can spot the differences in the internal frame.? There are two or three different frame types.

Steve Wedge, W1ES

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

Sent with secure email.

On Monday, May 26th, 2025 at 1:26 PM, David via groups.io <david.w5xu@...> wrote:
I would stay with one brand. Do not mix. RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf


Re: 6JB6A

 

¿ªÔÆÌåÓý

Hi David:

Yes, they're will not be mixed. All from the same brand, but not matched (from RF Parts). Interesting that on RCA tube description they say:? "For Horizontal-Deflection-Amplifier. For use in Drake Equipment.". May be ok on "T4" but not on TR(x)? U$35. But they have GE as well (U$39).

73
Marcus PY2PLL

Em 26/05/2025 14:26, David via groups.io escreveu:

I would stay with one brand. Do not mix.? RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU??? VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf

WRL- Galaxy IO Group

 

There is an IO group devoted to Leo Myerson's equipment. Leo made a huge impact on amateur radio.
If you have an interest, please join us at:
?
Tnx,
Dale W4OP
Re: Filament fuse blew

 

Filament is still in tact. Probably because I didn't give it enough time to blow again.
Mark
Current meter does not move when setting load during tune up.

 

When tuning up my second TR-4CW the current meter goes to 0 when I push in the load control to tune it.
I can see the load control working on my external power meter just nicely. I figured it was the switch.
I measured all 3 terminals on this switch compared to my other TR-4CW (that doesn't have this issue) and my
ohm measurements are pretty close so I believe the switch is OK.
Not sure what to do next?
Mark
Re: Filament fuse blew

 

¿ªÔÆÌåÓý

Did you check the filament fuse?

73
Mike W5RKL



On 5/26/25 4:33 PM, Mark N2DMI via groups.io wrote:

I was trying to re-seat the LSB bulb to the chassis because the bulb was intermittent. In doing so I think the positive side of the bulb housing touched ground some how because when I turned the TR-4CW back on and the amp meter light, frequency light, LSB, and USB lights were not lit. Then the filament fuse blew! I replaced the wire with #26 AWG and pulled both LSB and USB out and re-seated them and made sure nothing was shorting to ground. I quickly turned on the rig but still those lights would not light. The only light that I get is the round red light on the right side of the frequency read out. I connected my power supply to my other TR-4CW and that rig works OK so the power supply is still good. Not sure what is going on?
?
Mark
Filament fuse blew

 

I was trying to re-seat the LSB bulb to the chassis because the bulb was intermittent. In doing so I think the positive side of the bulb housing touched ground some how because when I turned the TR-4CW back on and the amp meter light, frequency light, LSB, and USB lights were not lit. Then the filament fuse blew! I replaced the wire with #26 AWG and pulled both LSB and USB out and re-seated them and made sure nothing was shorting to ground. I quickly turned on the rig but still those lights would not light. The only light that I get is the round red light on the right side of the frequency read out. I connected my power supply to my other TR-4CW and that rig works OK so the power supply is still good. Not sure what is going on?
?
Mark
Re: TR-4 AM Mode

 

¿ªÔÆÌåÓý

I should have clarified my statement by saying:


"The transmit speech amplifier's audio "alone" does not flow
through the IF filters."

73
Mike W5RKL



On 5/26/25 4:19 PM, Mike W5RKL via groups.io wrote:

The transmit speech amplifier's audio does not flow through the IF filters.
The "IF" filters are for "RF" not "AF".

The DSSC (Double Sideband Suppressed Carrier) signal from
the BM (Balance Modulator) flows through the LSB IF Filter (side
band switch must be set to "X" which selects the LSB filter).

To operate AM with a TR4 or any of the TR and T4/T4X<any>
transceivers or transmitter, the Side Band switch must be in
the "X" position which selects the "LSB" filter;

Any plug inserted into the "KEY" socket must be removed or
the plug shorted to ground in order to receive and transmit AM.
The same applies when operating SSB, the KEY socket must be
shorted to ground.

PTT and VOX work the same in AM mode as they do in SSB mode.

AM in the Drake TR series radios operates CCSM (Controlled
Carrier Screen Modulation). The Modulator stage controls the
level of the final amp's RF output. With no audio from the speech
amplifier applied to the Modulator stage, the Modulator stage keeps the final
amplifier's RF output at a low level, 8 to 10 watts. As the operator speaks
into the microphone, the speech amplifier audio applied to the AM modulator,
varies the final tubes screen voltage at the same rate as the speech amp
audio, hence CCSM AM is produced.

73
Mike W5RKL




On 5/26/25 12:43 PM, Gary WB6OGD via groups.io wrote:
In thinking about this, I think I see what is going on.
?
Audio goes the the screen modulator which modulates the gain of the final..?? I think this is that same as the old novice rigs like
the T-60 or DX-40.?? The carrier does go up and down with the modulation.? But you can hear it with a normal AM (diode) detector.
Drake marketing made it seem like something new and special, but it's really just old fashioned screen modulation.
?
I think the audio does not go through the crystal filter, only the carrier and it is not modulated.? It is fully DSB and full fidelity should result.
?
Right?
73,
Gary
WB6OGD
Re: TR-4 AM Mode

 

¿ªÔÆÌåÓý

The transmit speech amplifier's audio does not flow through the IF filters.
The "IF" filters are for "RF" not "AF".

The DSSC (Double Sideband Suppressed Carrier) signal from
the BM (Balance Modulator) flows through the LSB IF Filter (side
band switch must be set to "X" which selects the LSB filter).

To operate AM with a TR4 or any of the TR and T4/T4X<any>
transceivers or transmitter, the Side Band switch must be in
the "X" position which selects the "LSB" filter;

Any plug inserted into the "KEY" socket must be removed or
the plug shorted to ground in order to receive and transmit AM.
The same applies when operating SSB, the KEY socket must be
shorted to ground.

PTT and VOX work the same in AM mode as they do in SSB mode.

AM in the Drake TR series radios operates CCSM (Controlled
Carrier Screen Modulation). The Modulator stage controls the
level of the final amp's RF output. With no audio from the speech
amplifier applied to the Modulator stage, the Modulator stage keeps the final
amplifier's RF output at a low level, 8 to 10 watts. As the operator speaks
into the microphone, the speech amplifier audio applied to the AM modulator,
varies the final tubes screen voltage at the same rate as the speech amp
audio, hence CCSM AM is produced.

73
Mike W5RKL




On 5/26/25 12:43 PM, Gary WB6OGD via groups.io wrote:

In thinking about this, I think I see what is going on.
?
Audio goes the the screen modulator which modulates the gain of the final..?? I think this is that same as the old novice rigs like
the T-60 or DX-40.?? The carrier does go up and down with the modulation.? But you can hear it with a normal AM (diode) detector.
Drake marketing made it seem like something new and special, but it's really just old fashioned screen modulation.
?
I think the audio does not go through the crystal filter, only the carrier and it is not modulated.? It is fully DSB and full fidelity should result.
?
Right?
73,
Gary
WB6OGD
Re: Drake C Line For Sale

 

Hello Burt, still have this for sale?
joe
WA2L
Acworth, GA
Re: 6JB6A

 

From my experience, stick to GE or Sylvania.? Do not mix brands unless you can spot the differences in the internal frame.? There are two or three different frame types.

Steve Wedge, W1ES

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

Sent with secure email.

On Monday, May 26th, 2025 at 1:26 PM, David via groups.io <david.w5xu@...> wrote:

I would stay with one brand. Do not mix. RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf


Re: TR-4 AM Mode

 

In thinking about this, I think I see what is going on.
?
Audio goes the the screen modulator which modulates the gain of the final..?? I think this is that same as the old novice rigs like
the T-60 or DX-40.?? The carrier does go up and down with the modulation.? But you can hear it with a normal AM (diode) detector.
Drake marketing made it seem like something new and special, but it's really just old fashioned screen modulation.
?
I think the audio does not go through the crystal filter, only the carrier and it is not modulated.? It is fully DSB and full fidelity should result.
?
Right?
73,
Gary
WB6OGD
Re: 6JB6A

 

I would stay with one brand. Do not mix.? RcA also sells a longer version of the tube that will not fit so make sure you are getting the shorter version.

David Assaf III
W5XU??? VP8RXU

On Mon, May 26, 2025, 12:14 PM Marcus PY2PLL via <py2pll=[email protected]> wrote:
Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf

6JB6A

 

¿ªÔÆÌåÓý

Gentleman:

For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS.

Any recommendations?

73
Marcus PY2PLL + PY3CRX
GG66rf

Re: TR-4 AM Mode

 

This is the way most modern rigs create AM. It is SSB with carrier and has an emission designation. The audio response is limited by the bandwidth of the IF filter and the opposite sideband is attenuated by the filter. It's kind of like vestigial sideband, which TV guys will understand, but the opposite sideband would be VERY vestigial. If this is the actual method used in the TRx rigs than the screen modulation would be a long time constant gain control signal and not an audio modulation. OTOH if the screen is actually the AM modulation then audio into the balanced modulator should be removed in AM mode. Or maybe it is a mix of both. I don't know. Maybe I'll RTFM later....

On Mon, 26 May 2025 08:56:04 -0700
"Gary WB6OGD via groups.io" <winbladgary@...> wrote:

SO, if the carrier is shifted but the signal still goes through the filter..

It would be mostly DSB but with (greatly?) reduced fidelity, wouldn't it?? Or does one sideband have the bass and the other sideband
have the treble?

--

73

-Jim
NU0C
File /RCA_CA3053.pdf uploaded #file-notice

Group Notification
 

The following items have been added to the Files area of the [email protected] group.

By: Jim Shorney <jimNU0C@...>

Description:
RCA CA3053 differential amp IC data sheet
Re: Drake SPR-4 50 Khz IF and 50 Khz Filter alignment

 

It has been mentioned that T15 and T16 tune broadly. It may be that you will see little or no change with the adjustments. Are you sure your alignment tool isn't just spinning in a cracked slug? Those two adjustments are in the last stage of the IF so they will be dealing with relatively strong signal levels. It may be that you need a very weak signal to see any change. Perhaps a SINAD meter and a signal down into the noise would be a better method.

Your voltages on Q25 looked about right. I don't think there is a problem there. IC1 is a differential amplifier for IF circuits, sort of like an op amp. Drawing attached. I found two different pinouts, but this one from an old RCA data book I believe to be correct. I will upload the full data sheet to the group Files section.

It might be interesting to just skip for now T15 and T16 and try the adjustments for L11, L12, L13, and L14 so see if you have any change. You should be able to follow the DC voltage from the collector of Q25 to the AVC line and through Q14 and IC1 to see AVC action as you change the signal level. Disconnecting the gate of Q14 from the AVC line should eliminate possible leakage in Q14 as a problem. The AVC line should work but the S meter will not of course.

Disclaimer: I have no SPR4 experience. Just throwing things up against the wall to see if anything sticks. Hopefully this will spur some comments from ops who have actual experience.

On Mon, 26 May 2025 04:00:23 -0700
"enriqueeeeee2001 via groups.io" <enriqueeeeee2001@...> wrote:

I am trying to make a full alignment to a Drake SPR-4 but I have come across with an issue in the first step that the procedure manual indicates, any guidance would be greatly appreciated.

According to the point 5.3.1. I have connected a VTVM and the signal generato where indicated, I can adjust T17 for zero beat? but when adjusting T15 and T16 for maximum deflection there is no a slight movement neither in the voltmeter nor in the S-meter.

Due to the high impedance of the circuit , could be causing this the FET and IC located in the S-meter PCB?? I have seen modifications that recommend to replace them:



Anyone has had this problem before? Or could be caused by other elements.
--

73

-Jim
NU0C

2025-05-26_11h27_00.png

Thinning the shack Drake TR2770 transceiver for sale

 

The other night I was in the shack, and looked around at all the stuff I've gathered together over the years. It's time to let some of this stuff go. So, I've decided to sell my Drake TR2770. This is a rather rare two meter rig with a UHF receiver. Yeah, marketing really missed the mark with this product. It's been so long since I used it, but I'm thinking it does multimode, too. I set it up to talk on the local repeater.
?
Anyway... comes with the manual, power cord but no microphone. I rarely call something mint, but damn, this is about a close as mint as you can get.
?
I'm asking $375 plus shipping
?
Contact me off the list if interested.. at:?? prosolar@...
?
I'm Mike, WB8VGE
21 - 40 of 85105