Re: TR7 Service Kit - Extender Boards Needed
Can anybody tell me where to get the .156 connectors from please? Thanks Dave G4FAW
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Re: Need help with the planetary drive on T-4XC
Steve & Joe, I was suspecting that oiling the bearings could cause slipping. However, both of the veriers I have were packed with a thick grease. So, I will follow Steve's recommendation and try some wheel bearing grease, if for no?other reason, to make the assembly of the bearings possible. Something is needed to hold the bearings in place while the shaft is rotated around to each of the four positions.
On Thu, Mar 16, 2023 at 6:26?AM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: I use heavy wheel bearing?grease.? It provides plenty of friction. I won¡¯t look up the brand, as the jar of this stuff is from the 1950¡¯s and has been a lifetime supply for both my dad and me.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 15, 2023 at 10:35 PM, Joe WB9SBD < nss@...> wrote:
and NEVER OIL THEM. oil them
and 90% chance they will not work any longer. They NEED
friction to function.
Joe WB9SBD
On 3/15/2023 9:32 PM, wb6ogd wrote:
Bill,
These are planetary drives.. the "bearings" are actually like
gears, THEY are what you need to pre-load.
Clamp it end to end to compress the spring a little, then tighten
the screws.
That is my idea anyway.. having never worked on a C-line vernier,
hi hi...
73,
Gary
WB6OGD
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Re: Need help with the planetary drive on T-4XC
Gary, That is my plan. I am going to stop at Harbor Freight today and pick up an 8 in C clamp. I have been thinking about how the assembly should go. My?theory?of the moment is that the preload pressure on the spring sets the rotation tension (similar to the set screw on the PTO shaft) and the positioning of the large brass shaft aligns the bearing housing to be vertical. Not knowing what the preload should be, or anyway to measure it, it is probably going to be an iterative procedure. I will let you know how it goes.
Bill,
These are planetary drives..? the "bearings" are actually like gears, THEY are what you need to pre-load.
Clamp it end to end to compress the spring a little, then tighten the screws.
That is my idea anyway.. having never worked on a C-line vernier, hi hi...
73,
Gary
WB6OGD
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Re: Sourcing T4Xany cathode and screen grid resistors
Since I have several boxes full of resistors, I have simply been measuring the starting resistance and calculating what parallel resistance is needed. I trimmed the meter shunt to 1% and matched the cathode and grid resistor to 1-2%.?
On Wed, Mar 15, 2023 at 8:58?PM Doug Crompton WA3DSP < wa3dsp@...> wrote: There is NO reason these resistors need to be 1%. 5 or even 10% are fine and you can always select from a stash to match them if that is your thing. They don't even need to be exactly the specified resistance, as long as it is close and they are reasonably matched. Someone put 10 ohm 2W cathode resistors in my T4XC. That vaue would probably be more likely to be found. The only resistor that might benefit from being 1% is the 3.3 ohm meter shunt, but that is also a stretch given the accuracy of the meter itself.
--
Doug, WA3DSP
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Re: TR7 Service Kit - Extender Boards Needed
Hi, gang!
Several years ago, I came out with a set of extender boards for the TR7. They consisted of a board set for each specific card. One for the Audio/IF, another for the power supply/osc board, etc.?
They weren¡¯t big sellers, and thus I never made the set for the bottom cards. However, although not shown in the photos here, I did make a ¡®bridge¡¯ board to connect the cards necessary to run the transceiver without the DR board.
I will have to check the shop, but I think I have some of the bare/blank pcbs for the bridge board, maybe for some of the other ones, too.
These are expensive to make as they are large double sided pcbs to begin with and they are extremely labor intensive to assemble.?
Why is that? You ask?
Due to supply issues, sometimes you can get the 15 pin connector, so you need to use three 5 pin connectors. Oops, you can¡¯t get the five pin connectors, then you need four 3 pin connectors and a 2 pin connector. They all mate and match, so that¡¯s not problem. It¡¯s the jigsaw way you need to assemble the boards. It would really be nice to simply order the correct part.
If there is enough interest, (10 people for min pcb run) I can have another short run made.
That would be for 7 board, what is shown below and the bridge board.
NO connectors, $50 +$10 shipping priority mail.
73
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Re: Sourcing T4Xany cathode and screen grid resistors
Why not just buy from Mouser or Digikey? Both located in the USA.
Better pricing and more variety available and an excellent on line
catalog, no minimum order.
73, Jim W7RY
On 3/16/2023 7:31 AM, Steve Wedge,
W1ES/4 via groups.io wrote:
Yes, these guys are great. I¡¯ve bought lots of
caps from them.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Thu, Mar 16, 2023 at 1:57 AM, Doug Crompton WA3DSP <wa3dsp@...> wrote:
I often buy
parts from justradios.com - here is the resistor link -
Doug, WA3DSP
--
Thanks and 73, Jim W7RY
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Re: Sourcing T4Xany cathode and screen grid resistors
Yes, these guys are great. I¡¯ve bought lots of caps from them.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Thu, Mar 16, 2023 at 1:57 AM, Doug Crompton WA3DSP < wa3dsp@...> wrote: I often buy parts from justradios.com - here is the resistor link -
https://www.justradios.com/resistors.html
Doug, WA3DSP
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Re: Need help with the planetary drive on T-4XC
I use heavy wheel bearing?grease. ?It provides plenty of friction. I won¡¯t look up the brand, as the jar of this stuff is from the 1950¡¯s and has been a lifetime supply for both my dad and me.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 15, 2023 at 10:35 PM, Joe WB9SBD < nss@...> wrote:
and NEVER OIL THEM. oil them
and 90% chance they will not work any longer. They NEED
friction to function.
Joe WB9SBD
On 3/15/2023 9:32 PM, wb6ogd wrote:
Bill,
These are planetary drives.. the "bearings" are actually like
gears, THEY are what you need to pre-load.
Clamp it end to end to compress the spring a little, then tighten
the screws.
That is my idea anyway.. having never worked on a C-line vernier,
hi hi...
73,
Gary
WB6OGD
|
Re: Sourcing T4Xany cathode and screen grid resistors
I often buy parts from justradios.com - here is the resistor link -
https://www.justradios.com/resistors.html
Doug, WA3DSP
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Curious if anyone has ever used either a 12DQ7 or 12BV7 in place of the 12BY7 in a T4XC?? I have to search through my thousands of tubes and while I will primarily be looking for a 12BY7 I was just wondering if the other two would work. Characteristics seems very similar, and of course pin out is the same.
?
Doug, WA3DSP
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Re: Sourcing T4Xany cathode and screen grid resistors
Thanks for the practical, common sense application feedback guys.
For wattage it looks like I will stick with the original specs, maybe go 1 watt, and also not be overly focused on tighter value tolerance as long as the measured resistances are very close.
- Steve? W7SJT
"Always look for a positive solution then Improvise, Adapt, and Overcome" - adaptation of the U.S. Marine Corps motto "Every day is an opportunity to challenge the achievement of your dreams"
"Success is not final, failure is not fatal.? It is the courage to continue that counts."
-?Winston Churchill
On Wednesday, March 15, 2023 at 07:15:47 PM MDT, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
The fact that these 50-60 year old radios have continued running well on the parts that they were made from is a testament to their overall good design.?
Most of the problems appearing in these sets today are due to long-term ageing of the components.?
IMO, in most ¡ª but not all ¡ª situations, the original parts specs have served very well. When we replace an original part, most of us?will be long-gone before it will need replacement again.?
You won¡¯t go wrong replacing like with like.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 15, 2023 at 20:45, Rick WA6III < myr748@...> wrote: Even at? 400ma (total) cathode current, those 15¦¸ cathode resistors (@200ma ea)? would only dissipate (I2R) about 0.6W
Since no one (ever) operates a T4X key down at 400ma , 1W cathode resistors would have more than enough headroom....
6JB6 screen current per tube would have to be over 120ma for the screen resistor to dissipate 1w.? Somehow I think the screen current is a fraction of 120.
Just looked on eBay and found 15¦¸, 68¦¸ 1% 1w film type resistors for something like $3 and free shipping.
"10 Pieces 1 Watt 1% metal film resistors Over 200 Various Value YOU CHOOSE"
And if you want higher power ......
"10Pcs 5W 5 Watt Metal Film Resistor ¡À1% 0.1 - 91 ¦¸ Ohm 0.1 R to 91 R 6*17MM"
Just do a search for the above text on eBay.
Cheers,
Rick
--
73/Rick
WA6III
*Every post is created using Linux
|
Re: Sourcing T4Xany cathode and screen grid resistors
There is NO reason these resistors need to be 1%. 5 or even 10% are fine and you can always select from a stash to match them if that is your thing. They don't even need to be exactly the specified resistance, as long as it is close and they are reasonably matched. Someone put 10 ohm 2W cathode resistors in my T4XC. That vaue would probably be more likely to be found. The only resistor that might benefit from being 1% is the 3.3 ohm meter shunt, but that is also a stretch given the accuracy of the meter itself.
--
Doug, WA3DSP
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Re: Need help with the planetary drive on T-4XC
and NEVER OIL THEM.? oil them
and 90% chance they will not work any longer.? They NEED
friction to function.
Joe WB9SBD
On 3/15/2023 9:32 PM, wb6ogd wrote:
toggle quoted message
Show quoted text
Bill,
These are planetary drives..? the "bearings" are actually like
gears, THEY are what you need to pre-load.
Clamp it end to end to compress the spring a little, then tighten
the screws.
That is my idea anyway.. having never worked on a C-line vernier,
hi hi...
73,
Gary
WB6OGD
|
Re: Need help with the planetary drive on T-4XC
Bill,
These are planetary drives..? the "bearings" are actually like gears, THEY are what you need to pre-load.
Clamp it end to end to compress the spring a little, then tighten the screws.
That is my idea anyway.. having never worked on a C-line vernier, hi hi...
73,
Gary
WB6OGD
|
Re: Sourcing T4Xany cathode and screen grid resistors
I would stick to the Drake specs. too.
I know that the 1500 ohm 1/2 watt resistors that supply the B+ to the stages in the R-4 series work like fuses.
Put in a larger power one and possibly damage the attached series coil or other parts.?? Ask me how I know...
73,
Gary
WB6OGD
|
Re: Sourcing T4Xany cathode and screen grid resistors
Bravo my friend. ?73, Bill AE8EA
toggle quoted message
Show quoted text
On Mar 15, 2023, at 9:15 PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
? The fact that these 50-60 year old radios have continued running well on the parts that they were made from is a testament to their overall good design.?
Most of the problems appearing in these sets today are due to long-term ageing of the components.?
IMO, in most ¡ª but not all ¡ª situations, the original parts specs have served very well. When we replace an original part, most of us?will be long-gone before it will need replacement again.?
You won¡¯t go wrong replacing like with like.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 15, 2023 at 20:45, Rick WA6III < myr748@...> wrote: Even at? 400ma (total) cathode current, those 15¦¸ cathode resistors (@200ma ea)? would only dissipate (I2R) about 0.6W
Since no one (ever) operates a T4X key down at 400ma , 1W cathode resistors would have more than enough headroom....
6JB6 screen current per tube would have to be over 120ma for the screen resistor to dissipate 1w.? Somehow I think the screen current is a fraction of 120.
Just looked on eBay and found 15¦¸, 68¦¸ 1% 1w film type resistors for something like $3 and free shipping.
"10 Pieces 1 Watt 1% metal film resistors Over 200 Various Value YOU CHOOSE"
And if you want higher power ......
"10Pcs 5W 5 Watt Metal Film Resistor ¡À1% 0.1 - 91 ¦¸ Ohm 0.1 R to 91 R 6*17MM"
Just do a search for the above text on eBay.
Cheers,
Rick
--
73/Rick
WA6III
*Every post is created using Linux
|
Re: Sourcing T4Xany cathode and screen grid resistors
The fact that these 50-60 year old radios have continued running well on the parts that they were made from is a testament to their overall good design.?
Most of the problems appearing in these sets today are due to long-term ageing of the components.?
IMO, in most ¡ª but not all ¡ª situations, the original parts specs have served very well. When we replace an original part, most of us?will be long-gone before it will need replacement again.?
You won¡¯t go wrong replacing like with like.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Wed, Mar 15, 2023 at 20:45, Rick WA6III < myr748@...> wrote: Even at? 400ma (total) cathode current, those 15¦¸ cathode resistors (@200ma ea)? would only dissipate (I2R) about 0.6W
Since no one (ever) operates a T4X key down at 400ma , 1W cathode resistors would have more than enough headroom....
6JB6 screen current per tube would have to be over 120ma for the screen resistor to dissipate 1w.? Somehow I think the screen current is a fraction of 120.
Just looked on eBay and found 15¦¸, 68¦¸ 1% 1w film type resistors for something like $3 and free shipping.
"10 Pieces 1 Watt 1% metal film resistors Over 200 Various Value YOU CHOOSE"
And if you want higher power ......
"10Pcs 5W 5 Watt Metal Film Resistor ¡À1% 0.1 - 91 ¦¸ Ohm 0.1 R to 91 R 6*17MM"
Just do a search for the above text on eBay.
Cheers,
Rick
--
73/Rick
WA6III
*Every post is created using Linux
|
Re: Need help with the planetary drive on T-4XC
Peter, It looks like those might work, however, I suspect that there is no way to use the red pointer with one. I am still hoping to find out how to put the one I have back together. Nothing is broken- I just can't figure out how to get the preload on the bearings. Thanks for your suggestion. I will keep your idea as Plan B.
On Wed, Mar 15, 2023 at 2:59?PM VE7PS < ve7ps@...> wrote: How about installing a Jackson Bros 6:1 ball drive on the sub-panel?? You could even use one of the more rare, dual speed ones, for very precise control.? I've used these on homebrew?VHF amps with great success.? I can't think of why it wouldn't work there as well.? The one Drake used was a very cheap version of the same thing. Bean counter influence, no doubt, as they were around back then.
73 Peter VE7PS
Now I see..? the C-line is different from my A and B lines!
If it does depend on pre-load like you say, you just need a big clamp..? and remove the final cage and tubes.
My biggest clam is not big enough but you get the idea.
Or, nobody says you really need a vernier.? My early T-4X and the up to the early R-4A rigs didn't have them.
I even watched a YouTube recently that the guy bragged about the nice fast adjustment on his early rig!
Just freeze the two shafts somehow, maybe JB Weld or squeezing them?
73,
Gary
WB6OGD
|
Re: Sourcing T4Xany cathode and screen grid resistors
Even at? 400ma (total) cathode current, those 15¦¸ cathode resistors (@200ma ea)? would only dissipate (I2R) about 0.6W
Since no one (ever) operates a T4X key down at 400ma , 1W cathode resistors would have more than enough headroom....
6JB6 screen current per tube would have to be over 120ma for the screen resistor to dissipate 1w.? Somehow I think the screen current is a fraction of 120.
Just looked on eBay and found 15¦¸, 68¦¸ 1% 1w film type resistors for something like $3 and free shipping.
"10 Pieces 1 Watt 1% metal film resistors Over 200 Various Value YOU CHOOSE"
And if you want higher power ......
"10Pcs 5W 5 Watt Metal Film Resistor ¡À1% 0.1 - 91 ¦¸ Ohm 0.1 R to 91 R 6*17MM"
Just do a search for the above text on eBay.
Cheers,
Rick
--
73/Rick
WA6III
*Every post is created using Linux
|
Re: Need help with the planetary drive on T-4XC
Gary, My Plan A is to use a clamp just as you suggested, even if I need to fabricate one. However, after playing around with the vernier today I am not sure how to assemble it so it has the required preload. My initial thought results in a preload on the shafts, but not the bearings.I must be missing something really basic because this is not a complicated part. Thanks for your help. I'll let you know how it turns?out. If I can't get it to work again, I like your idea of just not worrying about the vernier and directly couple the shafts.
Now I see..? the C-line is different from my A and B lines!
If it does depend on pre-load like you say, you just need a big clamp..? and remove the final cage and tubes.
My biggest clam is not big enough but you get the idea.
Or, nobody says you really need a vernier.? My early T-4X and the up to the early R-4A rigs didn't have them.
I even watched a YouTube recently that the guy bragged about the nice fast adjustment on his early rig!
Just freeze the two shafts somehow, maybe JB Weld or squeezing them?
73,
Gary
WB6OGD
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Doug Crompton WA3DSP
Gary WB6OGD