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Early TR-4 cathode resistors, etc.

 

These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak.?

My question is re the resistors. Was this the original configuration? ?I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors.?

Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement.?

It¡¯s a late summer 1966 build (23xxx).?




Steve Wedge, W1ES

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


Sent from for iOS
 

That's how they look in my 26xxx TR-4.

Barry - N4BUQ

These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak.?

My question is re the resistors. Was this the original configuration? ?I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors.?

Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement.?

It¡¯s a late summer 1966 build (23xxx).?




Steve Wedge, W1ES

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


Sent from for iOS
 

Can you read the top of the label on the crystal filter . Interested in who made it, since I grew up in Cincinnati .
de WA8SDF


On Wed, Apr 16, 2025, 15:40 n4buq via <n4buq=[email protected]> wrote:
That's how they look in my 26xxx TR-4.

Barry - N4BUQ
These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak.?

My question is re the resistors. Was this the original configuration?? I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors.?

Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement.?

It¡¯s a late summer 1966 build (23xxx).?




Steve Wedge, W1ES

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


Sent from for iOS

IMG_5012.jpeg
IMG_5011.jpeg

 

Interesting.? I suppose I should do the maths now.

500ma for all 3 tubes/3=167 mA? .167^2= .027 * 15 ohms - 0.42W.

Yeah, that's within the power rating but obviously they decided to increase the headroom by going with a 1 W part later on.

This certainly shows that it's not helping at all by using 2 W resistors

These nearly 60-year-old resistors are measuring 15,7, 16,3 abd 17.2 (the rear tube -- which is where I have been finding more cathode resistors more out of tolerance.

Also interestingly, the screen resistors are all 67 to 68 ohms.

I'm having some difficulties with all three 10m bands both on receive and transmit.? This problem didn't clear when I changed all the bad / weak tubes.? Power out is 50 W and I can get 110 W out on 15 (these are well-used finals but they have plenty of power out on 15).? We've got something bad on 10m, so the quest continues!

Additional mind wandering: the PTO was quite loose on this.? You can get the PTO cover off without removing the PTO.? Remove the bubes immediately around the PTO, undo the spring, use fegular sharp-nosed pliers on the outboard side and right-angle pliers on the inboard, after removing the TUND and LOAD controls and shafts.? It tightened up nicely

73,

Steve Wedge, W1ES

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

Sent with secure email.

On Wednesday, April 16th, 2025 at 3:36 PM, n4buq <n4buq@...> wrote:

That's how they look in my 26xxx TR-4.

Barry - N4BUQ
These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak.?

My question is re the resistors. Was this the original configuration? ?I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors.?

Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement.?

It¡¯s a late summer 1966 build (23xxx).?




Steve Wedge, W1ES

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


Sent from for iOS
 

Tedford Crystal Lab, Inc.

Steve Wedge, W1ES

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

Sent with secure email.

On Wednesday, April 16th, 2025 at 4:07 PM, James Barrie via groups.io <barrie43@...> wrote:

Can you read the top of the label on the crystal filter . Interested in who made it, since I grew up in Cincinnati .
de WA8SDF


On Wed, Apr 16, 2025, 15:40 n4buq via <n4buq=[email protected]> wrote:
That's how they look in my 26xxx TR-4.

Barry - N4BUQ
These 1/2W resistors look original. I have yet to measure them but they don¡¯t look cooked. There are a couple of other places where the repair soldering isn¡¯t stellar but this rig right now is working on 80-15 with full (well, 100-150W) power and receive. I suspect that 10 needs an oscillator coil tweak.

My question is re the resistors. Was this the original configuration? I¡¯ve worked on very early T-4 and T-4X¡¯s that have 1W cathode resistors.

Also note the monolithic filter that was the originally used in the early sets ¡ª note there¡¯s no cutout in the chassis so this is the first soupcan replacement.

It¡¯s a late summer 1966 build (23xxx).




Steve Wedge, W1ES

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


Sent from for iOS

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