Re: T4XC help

#69880

If the plate current is pegged, it is way too much.? It is also a good way to go thru your supply of 6JB6 tubes.? You need to pull out the book and set the bias.? It is the best ally to save the tubes.? The Plate current will be about 280 ma and the power out (tube condition dependent) will be 100 watts + output.? I would not suspect the metering just yet.? With these transmitters, tuning for max output is not necessarily?the best way to promote final tube longevity.? After all, there is little discernible?difference between 100 watts and 120 watts.

Sounds like you have a nice radio.

Good Luck!

David Assaf III

W5XU, VP8RXU

?

Show quoted text

On Sun, Mar 12, 2023 at 12:18?AM Doug Crompton WA3DSP <wa3dsp@...> wrote:

Now that I have the AC4 rebuilt, I moved on to the T4XC. The transmitter was given to me probably 7 years ago by a now SK ham and has been stored by me since then. Probably not operated in over 10 years. It is a long story but he had two homes and he had to vacate one of them and his equipment ended up on the ground outside covered with a tarp outside. He called me and I got right over there and picked up the R4C/t4XC and MS4 as well as some other equipment. Fortunately, they had not been out there real long and were in fairly good shape. I would say good condition. The front panels are very good and the only sign of wear on both the RX and TX were that the chassis tops were discolored. Below chassis was very clean. This guy had an old pot-belly coal stove, and my suspicion is that the acids may have oxidized the chassis surface. It does not seem it did any other harm though.

So that's the backstory. I cleaned it, and deox'ed the tube sockets and controls/switches. First problem was the final filaments were out. Since they are series connected, I determined one of the 6JB6's had an open filament. Both tubes looked pretty beat so I replaced them with brand new 6JB6A's that I had. OK it now tunes up but since I have never had a Drake transmitter I have a few questions.

The bias was spot on according to the plate current meter. Surprising after the rebuild of the AC4 and sitting for all those years, but is the meter correct? Tune up on 80 meters gave good drive peak but the PA current does not seem right. The rig gives 100+ watts out but the PA meter is basically pegged at that power level.

The manual under CW tuning makes no mention of maximum PA current, but rather in section 3.12i says increase drive until there is no further increase in PA current. In my case that would be a pegged meter! I have not checked the meter shunt nor broken the PA voltage lead and measured actual current but I suspect the meter is not correct. Would 6JB6A's be any different than 6JB6's? I know I will need to check the neutralization but I don't think that is the issue here. Thoughts?

Doug, WA3DSP

Re: T4XC help

#69879

If your plate current t is pinning with the drive turned down, you may be losing your bias connection. Clean the blades of the Jones connector with DeOxIt and a Q tip.?

73,

Steve Wedge, W1ES/4

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

Sent from Proton Mail for iOS

Show quoted text

On Sun, Mar 12, 2023 at 01:18, Doug Crompton WA3DSP <wa3dsp@...> wrote:

Now that I have the AC4 rebuilt, I moved on to the T4XC. The transmitter was given to me probably 7 years ago by a now SK ham and has been stored by me since then. Probably not operated in over 10 years. It is a long story but he had two homes and he had to vacate one of them and his equipment ended up on the ground outside covered with a tarp outside. He called me and I got right over there and picked up the R4C/t4XC and MS4 as well as some other equipment. Fortunately, they had not been out there real long and were in fairly good shape. I would say good condition. The front panels are very good and the only sign of wear on both the RX and TX were that the chassis tops were discolored. Below chassis was very clean. This guy had an old pot-belly coal stove, and my suspicion is that the acids may have oxidized the chassis surface. It does not seem it did any other harm though.

So that's the backstory. I cleaned it, and deox'ed the tube sockets and controls/switches. First problem was the final filaments were out. Since they are series connected, I determined one of the 6JB6's had an open filament. Both tubes looked pretty beat so I replaced them with brand new 6JB6A's that I had. OK it now tunes up but since I have never had a Drake transmitter I have a few questions.

The bias was spot on according to the plate current meter. Surprising after the rebuild of the AC4 and sitting for all those years, but is the meter correct? Tune up on 80 meters gave good drive peak but the PA current does not seem right. The rig gives 100+ watts out but the PA meter is basically pegged at that power level.

The manual under CW tuning makes no mention of maximum PA current, but rather in section 3.12i says increase drive until there is no further increase in PA current. In my case that would be a pegged meter! I have not checked the meter shunt nor broken the PA voltage lead and measured actual current but I suspect the meter is not correct. Would 6JB6A's be any different than 6JB6's? I know I will need to check the neutralization but I don't think that is the issue here. Thoughts?

Doug, WA3DSP

Re: T4XC help

#69878

开云体育

I am sorry but I can't remember the exact value. It is important mainly in setting the idle bias. Again you can check the current at the 15 ohm cathode resistors.? They tend to go high .??

Unfortunately my lap top died so I have lost a lot of references.?

Show quoted text

-------- Original message --------

From: Doug Crompton WA3DSP <wa3dsp@...>

Date: 3/11/23 11:46 PM (GMT-08:00)

To: [email protected]

Subject: Re: [DRAKE-RADIO] T4XC help

OK, did a little further research. I have not checked it yet but the cathode current meter shunt is 2.7 ohms 1/2W. I see a replacement in a WB4HFN slide show uses three parallel 10 ohm 1/2W resistors. I suspect (and hope) this is the problem, since it is an easy fix.? Is the 3.3 ohms a compromise, or should I parallel to get closer a measured 2.7 ohms as shown on the schematic?
--
Doug, WA3DSP

Re: T4XC help

#69877

OK, did a little further research. I have not checked it yet but the cathode current meter shunt is 2.7 ohms 1/2W. I see a replacement in a WB4HFN slide show uses three parallel 10 ohm 1/2W resistors. I suspect (and hope) this is the problem, since it is an easy fix.? Is the 3.3 ohms a compromise, or should I parallel to get closer a measured 2.7 ohms as shown on the schematic?
--
Doug, WA3DSP

Re: T4XC help

#69876

开云体育

Two sites to bookmark.

K4AOH. Order Garry barrell's ca for the C line. Available from his wife. You can download them.? Not expensive.?

?WB4HFN. Has tons of stuff.

Study the metering circuit.? Note that each tube has a 15 ohm cathode resistor.? Measure these to make sure they are accurate.? Replace if not.? Use thick film resistors.? The tube current can be measured as the drop across these.? Meter measures total current,? that is the combined plate and screen current.

Check all other resistors in the meter circuit.

?Make sure you understand the tune up procedure.? ?It is relatively conventional.? Drive must be peaked at a.low level. Then tune plate for a dip and peak the load for maximum output on the rf meter or external watt meter. Alternate between plate dip and load peak until output is maximized,? then increase drive and do it again. At maximum output you should have about 300ma plate current ( I am going by memory, check the book).? Tune up in TUNE you can push out a few more watts in CW but it's not good practice.

Plate load should be set a little below maximum output.? _ALWAYS_dip the plate last.? HV will be around 650V.? Maximum output depends on frequency and condition of tubed, max around140 watts at 40 meters.? In SSB? the ALC limits output to around 125 watts.?

The plate meter should never pin in normal operation.?

Read the material referred to.? My memory is getting old.?

Show quoted text

-------- Original message --------

From: Doug Crompton WA3DSP <wa3dsp@...>

Date: 3/11/23 10:18 PM (GMT-08:00)

To: [email protected]

Subject: [DRAKE-RADIO] T4XC help

Now that I have the AC4 rebuilt, I moved on to the T4XC. The transmitter was given to me probably 7 years ago by a now SK ham and has been stored by me since then. Probably not operated in over 10 years. It is a long story but he had two homes and he had to vacate one of them and his equipment ended up on the ground outside covered with a tarp outside. He called me and I got right over there and picked up the R4C/t4XC and MS4 as well as some other equipment. Fortunately, they had not been out there real long and were in fairly good shape. I would say good condition. The front panels are very good and the only sign of wear on both the RX and TX were that the chassis tops were discolored. Below chassis was very clean. This guy had an old pot-belly coal stove, and my suspicion is that the acids may have oxidized the chassis surface. It does not seem it did any other harm though.

So that's the backstory. I cleaned it, and deox'ed the tube sockets and controls/switches. First problem was the final filaments were out. Since they are series connected, I determined one of the 6JB6's had an open filament. Both tubes looked pretty beat so I replaced them with brand new 6JB6A's that I had. OK it now tunes up but since I have never had a Drake transmitter I have a few questions.

The bias was spot on according to the plate current meter. Surprising after the rebuild of the AC4 and sitting for all those years, but is the meter correct? Tune up on 80 meters gave good drive peak but the PA current does not seem right. The rig gives 100+ watts out but the PA meter is basically pegged at that power level.

The manual under CW tuning makes no mention of maximum PA current, but rather in section 3.12i says increase drive until there is no further increase in PA current. In my case that would be a pegged meter! I have not checked the meter shunt nor broken the PA voltage lead and measured actual current but I suspect the meter is not correct. Would 6JB6A's be any different than 6JB6's? I know I will need to check the neutralization but I don't think that is the issue here. Thoughts?

Doug, WA3DSP

T4XC help

#69875

Now that I have the AC4 rebuilt, I moved on to the T4XC. The transmitter was given to me probably 7 years ago by a now SK ham and has been stored by me since then. Probably not operated in over 10 years. It is a long story but he had two homes and he had to vacate one of them and his equipment ended up on the ground outside covered with a tarp outside. He called me and I got right over there and picked up the R4C/t4XC and MS4 as well as some other equipment. Fortunately, they had not been out there real long and were in fairly good shape. I would say good condition. The front panels are very good and the only sign of wear on both the RX and TX were that the chassis tops were discolored. Below chassis was very clean. This guy had an old pot-belly coal stove, and my suspicion is that the acids may have oxidized the chassis surface. It does not seem it did any other harm though.

So that's the backstory. I cleaned it, and deox'ed the tube sockets and controls/switches. First problem was the final filaments were out. Since they are series connected, I determined one of the 6JB6's had an open filament. Both tubes looked pretty beat so I replaced them with brand new 6JB6A's that I had. OK it now tunes up but since I have never had a Drake transmitter I have a few questions.

The bias was spot on according to the plate current meter. Surprising after the rebuild of the AC4 and sitting for all those years, but is the meter correct? Tune up on 80 meters gave good drive peak but the PA current does not seem right. The rig gives 100+ watts out but the PA meter is basically pegged at that power level.

The manual under CW tuning makes no mention of maximum PA current, but rather in section 3.12i says increase drive until there is no further increase in PA current. In my case that would be a pegged meter! I have not checked the meter shunt nor broken the PA voltage lead and measured actual current but I suspect the meter is not correct. Would 6JB6A's be any different than 6JB6's? I know I will need to check the neutralization but I don't think that is the issue here. Thoughts?

Doug, WA3DSP

Re: "C-7" Console

Lyndon Nerenberg (VE7TFX/VE6BBM)

#69874

Jim Shorney writes:
 
Just make it C-75 and you're good either way.You, sir, are a Geeeenius! :-)

Also, then it will match the PS-75.

--lyndon

Re: "C-7" Console

#69873

Just make it C-75 and you're good either way.

73

-Jim
NU0C

On Sat, 11 Mar 2023 15:31:11 -0800
"Lyndon Nerenberg (VE7TFX/VE6BBM)" <lyndon@...> wrote:

VE7PS writes:

Now you need to change the number on the console!

Or buy a TR-7......  Oh shut up! :-)

Either way...congrats on the new rig!  I was in no position to afford it, but it popped up out of the blue
and there was no way I was going to let it get away (just like the
TR-6).

I am really looking forward to getting it on the air and trying out
the QSK.  And the lower power is actually a benefit right now.
Being an apartment dweller, belting out 180W from the C-line into
a balcony-strung doublet might be considered a bit rude.  I should
have the doublet put together and strung next week.  I probably
won't be able to hear anything on HF, due to the insane levels of
local QRN, but I'm hoping it will be low enough on 10m and 12m that
I might be able to pull off some contacts, now that those bands
seem to be opening up.

I also got the 6m Omniangle installed today, but the coax run came
up a bit short, so that will have to wait for a week while I wait
for some coax extensions to arrive.  Sadly, I won't be able to power
up the TR-6 (same QRO issues as above), so I'll be firing up the
TS-2000 to talk to it (and the 2m Omniangle).  I'm really hoping
6m decides to open up this summer.  (Okay, I will probably cheat
and crank up the TR-6 once or twice, just becausse :-)  Maybe the
TC-2, too.)

--lyndon)

P.S.  Anybody want to trade their SL-300 for an SL-1800?

Re: "C-7" Console

Lyndon Nerenberg (VE7TFX/VE6BBM)

#69872

VE7PS writes:

Now you need to change the number on the console!

Or buy a TR-7......Oh shut up! :-)

Either way...congrats on the new rig!I was in no position to afford it, but it popped up out of the blue
and there was no way I was going to let it get away (just like the
TR-6).

I am really looking forward to getting it on the air and trying out
the QSK.  And the lower power is actually a benefit right now.
Being an apartment dweller, belting out 180W from the C-line into
a balcony-strung doublet might be considered a bit rude.  I should
have the doublet put together and strung next week.  I probably
won't be able to hear anything on HF, due to the insane levels of
local QRN, but I'm hoping it will be low enough on 10m and 12m that
I might be able to pull off some contacts, now that those bands
seem to be opening up.

I also got the 6m Omniangle installed today, but the coax run came
up a bit short, so that will have to wait for a week while I wait
for some coax extensions to arrive.  Sadly, I won't be able to power
up the TR-6 (same QRO issues as above), so I'll be firing up the
TS-2000 to talk to it (and the 2m Omniangle).  I'm really hoping
6m decides to open up this summer.  (Okay, I will probably cheat
and crank up the TR-6 once or twice, just becausse :-)  Maybe the
TC-2, too.)

--lyndon)

P.S.  Anybody want to trade their SL-300 for an SL-1800?

Re: "C-7" Console

#69871

Lyndon...

Now you need to change the number on?the console!

Or buy a TR-7......

Either way...congrats on the new rig!

73

Peter

VE7PS

Virus-free.

Show quoted text

On Sat, Mar 11, 2023 at 2:29?PM Lyndon Nerenberg (VE7TFX/VE6BBM) <lyndon@...> wrote:

> On Sat, Dec 17, 2022 at 3:52 PM Lyndon Nerenberg (VE7TFX/VE6BBM) <
> lyndon@...> wrote:
[ ... ]
> > I'm worried that, if I keep this console around in its present form for
> > too long, I will end up buying a TR-7 to match :-)

I was wrong.

--lyndon

Re: "C-7" Console

Lyndon Nerenberg (VE7TFX/VE6BBM)

#69870

On Sat, Dec 17, 2022 at 3:52 PM Lyndon Nerenberg (VE7TFX/VE6BBM) <
lyndon@...> wrote:[ ... ]
I'm worried that, if I keep this console around in its present form for
too long, I will end up buying a TR-7 to match :-)I was wrong.

--lyndon

oops.jpeg

Re: Drake TR5 schematic

#69869

Correction:

It is the MRF 455 Finals I have

Marty

KL7AM

Show quoted text

From: "w7apm" <w7apm@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Saturday, March 11, 2023 8:29:10 AM
Subject: Re: [DRAKE-RADIO] Drake TR5 schematic

I have new matched pairs of driver transistors for the TR-5

Contact me off list if interested

Marty

KL7AM

From: "Jim Harris" <radiove1rb@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Thursday, March 9, 2023 3:21:45 PM
Subject: Re: [DRAKE-RADIO] Drake TR5 schematic

Thank you Ken and it looks better. Still have to fix my TR& as it does not transmit either hi.

73, Jim

On 2023-03-09 16:11, Ken, WA2LBI wrote:

Jim,

Is the?attached better than?yours?

Ken

WA2LBI

On Thu, Mar 9, 2023 at 2:51?PM Jim Harris <radiove1rb@...> wrote:

Does anybody have a good clean clear copy of the schematic for the TR5? Or maybe a place I can download one. I have one but when you blow it up the resolution is terrible as lines are missing etc. I am trying to get the tranmsitter putting out power. I have already installed a new pair of matched finals as one was bad and now I have found that the RX/TX, TX mixed for the transmitter was bad and the 2N4427 had a base to collector short and that took out the base resistor. I have a couple new transistors but would like to make sure there are no other problem around the TX mixer. Thank you.

Jim VE1RB

Re: Drake TR5 schematic

#69868

I have new matched pairs of driver transistors for the TR-5

Contact me off list if interested

Marty

KL7AM

Show quoted text

From: "Jim Harris" <radiove1rb@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Thursday, March 9, 2023 3:21:45 PM
Subject: Re: [DRAKE-RADIO] Drake TR5 schematic

Thank you Ken and it looks better. Still have to fix my TR& as it does not transmit either hi.

73, Jim

On 2023-03-09 16:11, Ken, WA2LBI wrote:

Jim,

Is the?attached better than?yours?

Ken

WA2LBI

On Thu, Mar 9, 2023 at 2:51?PM Jim Harris <radiove1rb@...> wrote:

Does anybody have a good clean clear copy of the schematic for the TR5? Or maybe a place I can download one. I have one but when you blow it up the resolution is terrible as lines are missing etc. I am trying to get the tranmsitter putting out power. I have already installed a new pair of matched finals as one was bad and now I have found that the RX/TX, TX mixed for the transmitter was bad and the 2N4427 had a base to collector short and that took out the base resistor. I have a couple new transistors but would like to make sure there are no other problem around the TX mixer. Thank you.

Jim VE1RB