On Mar 21, 2024, at 6:39?PM, Kevin W2TVS via groups.io <johnlamondwyrk@...> wrote:

?Just had my R4A restored by WB4HFN and it gives you S9 to 20 over static when you first turn it on. ?It lasts for about one to two minutes and then goes away. ?I think this is normal for these radios. Once it warms up, then it is fine.

Just had my R4A restored by WB4HFN and it gives you S9 to 20 over static when you first turn it on. ?It lasts for about one to two minutes and then goes away. ?I think this is normal for these radios. Once it warms up, then it is fine.

On Mar 21, 2024, at 3:49?PM, Paul Kraemer <elespe@...> wrote:

That is correct.? Eimac almost no orange with same drive and output as the RFP

I had to put it aside for bench space for more pressing matters.? I'll try to fill in all the blanks next week

Paul

On 3/21/2024 2:47 PM, Gary Follett wrote:

Then you see almost no orange with the Eimac tubes when driven with 89 watts?

What plate current readings do you get with each set of tubes driven with 50 watts and output power? (I picked a lower value for the sake of the tubes). I’m trying to get at how efficiently the amp is running with different tubes. The brighter glow on the plates simply means the newer tubes are dissipating more heat than the Eimac tubes (due to poorer efficiency) or the newer tube design itself is less efficient at disposing of plate heat than the old Eimac tubes.

It is quite possible that the emissivity of the newer plates is less than the iMac’s, and this would make them run hotter than the Eimac’s.?

Gary

W0DVN

On Mar 21, 2024, at 2:18?PM, Paul Kraemer <elespe@...> wrote:

Both import tubes look same color orange

This is keyed and 89w drive applied on all bands

Idle current approx 100ma total either tube type with hv 2650v

Paul K0UYA

On 3/21/2024 12:21 PM, Gary Follett wrote:

Do both tubes show the same degree of orange? Is this when keyed but with no drive?

What is the idle plate current, with the Eimac tubes, then the other tubes?

Gary

W0DVN

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

Then you see almost no orange with the Eimac tubes when driven with 89 watts?

What plate current readings do you get with each set of tubes driven with 50 watts and output power? (I picked a lower value for the sake of the tubes). I’m trying to get at how efficiently the amp is running with different tubes. The brighter glow on the plates simply means the newer tubes are dissipating more heat than the Eimac tubes (due to poorer efficiency) or the newer tube design itself is less efficient at disposing of plate heat than the old Eimac tubes.

It is quite possible that the emissivity of the newer plates is less than the iMac’s, and this would make them run hotter than the Eimac’s.?

Gary

W0DVN

On Mar 21, 2024, at 2:18?PM, Paul Kraemer <elespe@...> wrote:

Both import tubes look same color orange

This is keyed and 89w drive applied on all bands

Idle current approx 100ma total either tube type with hv 2650v

Paul K0UYA

On 3/21/2024 12:21 PM, Gary Follett wrote:

Do both tubes show the same degree of orange? Is this when keyed but with no drive?

What is the idle plate current, with the Eimac tubes, then the other tubes?

Gary

W0DVN

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

On Mar 21, 2024, at 2:18?PM, Paul Kraemer <elespe@...> wrote:

Both import tubes look same color orange

This is keyed and 89w drive applied on all bands

Idle current approx 100ma total either tube type with hv 2650v

Paul K0UYA

On 3/21/2024 12:21 PM, Gary Follett wrote:

Do both tubes show the same degree of orange? Is this when keyed but with no drive?

What is the idle plate current, with the Eimac tubes, then the other tubes?

Gary

W0DVN

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

Do both tubes show the same degree of orange? Is this when keyed but with no drive?

What is the idle plate current, with the Eimac tubes, then the other tubes?

Gary

W0DVN

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??

We are at -1.345 at TP2 detuned and no antenna connected.

After swapping V4&V5 I did no adjustment to the circuit.

On Wed, Mar 20, 2024 at 8:52?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Well, this is vexing,

The Drake AGC circuit is very high impedance: on the order of megohms. It is employed to control the gain of the various stages by changing the bias voltage.

It has been awhile, so please excuse me if this is repetitive, but what is the bias voltage at TP2?

Steve Wedge, W1ES/4

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

Sent with secure email.

On Wednesday, March 20th, 2024 at 3:06 PM, Michael Jensen <kavigal@...> wrote:

Okay quick info on progress on the saga...

Replaced V4&V5 with 2 NOS tubes, that brought the meter down from ~5-6 S units to ~4 S units, still the zero pot needs to be maxed/minimize depending how we look at it.

Replaced V3 as well since I got hold of an 12BE6, made no differens.

I totally forgot I had several 12au6's / EF94 in stock, changed V2, just for the fun of it, made no change as expected though.

So, back to the drawing board.

Cheers..

On Sat, Mar 9, 2024 at 9:05?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Crackling sounds that affect the AGC (and thus cause the meter to deflect) are worthy of investigation. You may have a component that is either cracking (resistor) or has some intermittent dialectric issues (capacitor).

I have been promising myself that I would look into creating one of those "Mr. Carlson Super Probes". "Mr. Carlson's Lab" is on YouTube and he created an AC probe that can sniff out problems like internally arcing components. The probe is similar in concept to the old signal tracers but it is much more sensitive. I believe he has two versions: one with through-hole and the other using SMT. He demonstrated the probe on an old receiver that was showing "crackling" noises. and was able to find the bad cap within a few minutes.

Anyway, I scored another victory today: I figured out how to add a 3rd monitor to the shack computer! More screen area -- yay!

73,

Steve Wedge, W1ES/4

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

Sent with secure email.

On Saturday, March 9th, 2024 at 1:14 PM, Michael Jensen <kavigal@...> wrote:

Well sorry for the slow reply, work just tend to take up too much of one's spare time ;).

Sounds like a very nice trip you and XYL is planning, now I do not travel much these days(I used to), now I just mainly work from home and enjoy monitoring the HF bands, when 'Teams' decides to leave me alone ;).

About that Beer.. Guess I already owe you one, at least as an excuse to get myself one.

Been a few years since I was in Copenhagen, I live in the opposite end of the country all the way up to the North about 50KM south of the most northern point..

And yes we will get to the bottom of this issue, actually I notice something, when I turn on the radio 'ON' to "standby" position the meters consequential "jumps" from ~S9+20 to the S9+40 meter mark, first time I noticed I just though "ohh meter is sticky" but then while troubleshooting I fiddled with the RF gain and guess what?

No "sticky" meter when RF gain is fully cranked up quickly.

I noticed twice when "cold" starting the rig, and coinciding "crackling" sound when the meter "jumped", not sure what the right term is in English / U.S.A'ish but same sound a hot 6146B tube can produce just not so pronounced.

It may not be related, just noticed it.. So.. status quo, really eager to get that 12be6 swapped, but the mail man is apparently on vacation in Hawaii current time.

/Michael.

On Thu, Mar 7, 2024 at 6:48?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Yeah, that's a shame that we still have such impediments. In the grand scheme of things, a few 60 year old tubes are nothing. If I was going to Demark this year, I'd pop a couple in my bag and trade them for a beer but we will not be in the area. We will be in HB9, DL, OE, OK, F, G, GW, GM and TF this summer. My XYL is not a ham, so I'm not bringing any radios, unfortunately :-) I mention this in case you're in any of these areas in June or July.

In a couple years, perhaps, we will get to Scandinavia. I worked in Copenhagen for a week long ago and have wanted to tour that area.

We will get to the bottom of this.

73,

Steve Wedge, W1ES/4

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

Sent with secure email.

On Thursday, March 7th, 2024 at 12:26 PM, Michael Jensen <kavigal@...> wrote:

Steve, I'd love the approach of shotgunning, but nope I do not have a complete set.

I do have 2x12ba6 in the mail and 1 12be6 also in the mail, so that will be the starting point.

I did consider and I'd love to get a complete set from K5SVC, but it would add more than 4 times
the money I have in the R4B already, getting tubes from the US to Europe is .. insane..
So thank you to the Danish Government ;)

Anyways, will try the three tube change first, that's kinda where I'm at now.

/Michael

On Thu, Mar 7, 2024 at 5:33?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Now is the time, if you either have a spare set or have another R-4B, to swap every tube out at the same time (“shotgunning”).

I had an R-4B that was vexing me to no end until I replaced all the tubes and then put swapped the old ones back, one at a time. I found two bad/gassy 12BA6’s and a 12BE6 that passed the tube tester but was no good.

Steve Wedge, W1ES/4

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

Sent from for iOS

On Thu, Mar 7, 2024 at 09:29, Michael Jensen <kavigal@...> wrote:

When unpowered, S1+a hair, so very close to zero.

Have checked the following resistors so fare...

Just FYI, nothing more..

R9 1.5K** Board 9 OK
R8 220K** Chassis Right Side -R OK
R12 1.5k**Board 9 OK
R13 1.5K**Board 9 OK
R16 1.5K**Board 7 OK
R17 12K* OK
R24 18K* OK

R136 1k** Chassis Left Side -R OK
R142 4.7K**Board 3 OK
R146 22K** Board 3 -- coil OK

/Michael.

On Thu, Mar 7, 2024 at 3:19?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Yes, I have been bit by one of the meter terminals. It hurts :-). This circuit is at around 150V potential.

Steve Wedge, W1ES/4

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

Sent from for iOS

On Thu, Mar 7, 2024 at 01:23, Glenn, OZ1HFT <glenn.mh.dk@...> wrote:

Hi Michael

More safety: Let the Drake unlugged power plug and cable be visible to you, on your workbench, while you work on the Drake.

(Then it be much harder to get an accidently electric shock.)

--
best regards,

Glenn, OZ1HFT

On Mar 20, 2024, at 8:39?PM, Paul Kraemer <elespe@...> wrote:

Please enlighten me Gary.? With the imports installed the tune and load just didn't "feel" right and it was interesting to me that there was a faint orange glow for nominal power output(same in both cases)while the Eimac exhibited none of that.? Neither set could be classified as nearly new but that is what I observed. What is sold today may be totally different than what was sold then.

Paul

On 3/20/2024 8:22 PM, Gary Follett wrote:

Well, aside from marginal vacuum, the RF Parts tubes are good. They just have more gain than the originals, and this makes them more susceptible to instability.

There are parasitic choke upgrades available and they work pretty well.

Gary

W0DVN

On Mar 20, 2024, at 8:20?PM, Paul Kraemer <elespe@...> wrote:

The L7 I recently had instability problems and tune capacitor arc has been REPAIRED. ?I managed with time and a jeweler file to clean the burn from the capacitor plate without removing it. ?I gingerly tried the amp again and although it didn't arc the same spot it started in other spots on the tune capacitor. ?Inspecting closely I found the tubes looked like Eimac but they were imports from RF Parts. ?I changed those out for some OLD Eimac and very pleased to report PROBLEM SOLVED. ?Everything behaved and tuning / loading adjust is now smooth as glass with NO instability. ?It is as it should be on all bands!

Not to imply the RF Parts tubes are not good but the subtle differences between Eimac and those particular import ARE significant. ?Now to find good tubes for the next time

Paul K0UYA

Well, aside from marginal vacuum, the RF Parts tubes are good. They just have more gain than the originals, and this makes them more susceptible to instability.

There are parasitic choke upgrades available and they work pretty well.

Gary

W0DVN

On Mar 20, 2024, at 8:20?PM, Paul Kraemer <elespe@...> wrote:

The L7 I recently had instability problems and tune capacitor arc has been REPAIRED. I managed with time and a jeweler file to clean the burn from the capacitor plate without removing it. I gingerly tried the amp again and although it didn't arc the same spot it started in other spots on the tune capacitor. Inspecting closely I found the tubes looked like Eimac but they were imports from RF Parts. I changed those out for some OLD Eimac and very pleased to report PROBLEM SOLVED. Everything behaved and tuning / loading adjust is now smooth as glass with NO instability. It is as it should be on all bands!

Not to imply the RF Parts tubes are not good but the subtle differences between Eimac and those particular import ARE significant. Now to find good tubes for the next time

Paul K0UYA