Re: Success- the vernier drive on my T-4XC is back together and working.
I tend to leave the drive alone unless there¡¯s a problem with moving the slug rack. The problem usually manifests itself at the high frequency end (10m). If resetting the preload won¡¯t fix it, then I¡¯ll take it out, clean it, inspect it and try to reposition the shaft as needed after putting in new grease.?
Even when I wash the chassis, I won¡¯t take apart a working drive. I keep the detergent away from the drive.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
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On Fri, Mar 17, 2023 at 21:36, Bill Leonard N0CU < billincolo73@...> wrote: After trying unsuccessfully for several days to reassemble the vernier drive on my T-4XC, I noticed a small ball bearing on the carpet under my work bench. Since the vernier drive is the only thing I had been working on that had any bearings, I assumed that it must have fallen out of the drive while I was removing it from the T-4XC. It turns out that this bearing is used as a spacer inside the large shaft. After placing it next to the spring inside the large shaft, I was able to reassemble the drive with just a slight amount of preload. The preload required is only that required to get the set screws on the large shaft to fit into the notch on the main shaft. The main shaft is the one that moves the coil slugs. The preload needed can easily be generated by a medium size screwdriver and no special clamp is required. Although removing the vernier allowed me to remove all of the old grease, I am not sure the improvement over what was achieved by simply cleaning the drive in place justifies the extra work involved in reassembling the drive.
--
Bill N0CU
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Success- the vernier drive on my T-4XC is back together and working.
After trying unsuccessfully for several days to reassemble the vernier drive on my T-4XC, I noticed a small ball bearing on the carpet under my work bench. Since the vernier drive is the only thing I had been working on that had any bearings, I assumed that it must have fallen out of the drive while I was removing it from the T-4XC. It turns out that this bearing is used as a spacer inside the large shaft. After placing it next to the spring inside the large shaft, I was able to reassemble the drive with just a slight amount of preload. The preload required is only that required to get the set screws on the large shaft to fit into the notch on the main shaft. The main shaft is the one that moves the coil slugs. The preload needed can easily be generated by a medium size screwdriver and no special clamp is required. Although removing the vernier allowed me to remove all of the old grease, I am not sure the improvement over what was achieved by simply cleaning the drive in place justifies the extra work involved in reassembling the drive.
-- Bill N0CU
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For what it's worth, Drake does call it AGC on the schematic.? His statement as I read it is saying that as shipped with the 1 Meg AGC does not work properly and adding the 15K makes it work, At least that's the way I read it. It is also stated this was fixed in later T4's.
I saw this statement in another search -
The 15k AGC resistor is wired across the 1meg AGC resistor that was installed by the factory.? At least that is what Drake did in my T4X.? The 1meg was a design mistake by Drake that was fixed in later models.? A quick solution to the problem was to simply wire a 15k across the 1meg and settle for slightly less than 15k.? With a 1meg resistor there was no AGC.
Regards,
Frank Kamp, K5DKZ,? July 14, 2002
I wonder if K5DKZ is a member of this group? Perhaps he can explain it.
?
Doug, WA3DSP
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I have read that years ago, noted it on my schematic.
I do find it hard to believe a Drake factory screw up that makes it to not work!
I do have my T-4X on the bench right now, I will try to check it out.
I remember back in the day guys were bending a tube pin out to disconnect all ALC..? made for a bigger signal but with splatter.
They were hams but thought like CBer's.? Lowering that resistor might do pretty much the same.
Yes, AGC is ALC..? I am pretty sure Drake called it ALC, he is the only one calling it AGC, though it is the same.
Gain vs. Level.. pretty much the same to me, hi hi.
73,
Gary
WB6OGD
?
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In this article on conversion to 6146's? -? He states the following. This seems like a radical change of value. Is this valid? Exactly what does AGC do? Is this really better termed ALC?
Connect a 15k ohm, half watt resistor from the plate of V1B (AGC amp) to ground. This may only be needed on the T4X to correct a factory screw-up. The original value of the resistor here was 1 meg which would ensure that there was no AGC action. No one really noticed so it may not be a big deal. If you want the AGC to work on an old T4X, install the 15k resistor. No need to remove the original 1 meg resistor, just wire the 15k across it.
Doug, WA3DSP
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Re: TR7 Service Kit - Extender Boards Needed
Yes, finding .156 connectors is easy, perhaps I should've asked ones that are compatible with the originals as far as pin dia is concerned along with the hooks that hook over the edge of the pcb so the connector is not distorted when plugged in and unplugged.... Thanks for your help.
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Re: TR7 Service Kit - Extender Boards Needed
Mark,
No, tell ron to keep the listing for me.
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
.com/
J e e p
o|||||||o?
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On Mar 16, 2023, at 7:45 PM, Mark - WB0IQK < mgilger@...> wrote:
I'll let Ron know to remove Bob's ad for those boards. He might have forgotten to advise him that they were all sold.?
Mike, should I remove your boards from the parts & service doc on his site??
73's,
Mark
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BTW a 12GN7 while not a direct substitute has the same pinout and is about twice the plate dissipation and higher transconductance than the 12BY7. I could not find one to try but it would be an interesting to try if you could find one. It would definitely require retuning.
--
Doug, WA3DSP
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I think I have answered my own question. These tubes are basically one and the same. I found quite a few in my stash, and this RCA is numbered with all three types. I ended up using a JAN GE 12BY7A which worked fine.
--
Doug, WA3DSP
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Re: TR7 Service Kit - Extender Boards Needed
I'll let Ron know to remove Bob's ad for those boards. He might have forgotten to advise him that they were all sold.?
Mike, should I remove your boards from the parts & service doc on his site??
73's,
Mark
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Looking for a Excellent top cabinet if anyone knows where I might find one.
An excellent original R7A manual would be nice too.
Marty
KL7AM
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Re: TR7 Service Kit - Extender Boards Needed
Mike, FYI in Drake parlance this is known as the "Jumper Board" and is described as such in the TR7 service manual. 73 -Jim NU0C On Thu, 16 Mar 2023 11:07:38 -0400 "Mike Bryce" <prosolar@...> wrote: I did make a ¡®bridge¡¯ board to connect the cards necessary to run the transceiver without the DR board.
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Re: Sourcing T4Xany cathode and screen grid resistors
I don¡¯t have the answer to that. I did, however, throw out some carbon resistors recently (and I¡¯m in an ongoing process with my stock, which dates back decades) that were grossly out of spec, even for 10 or 20% parts. Those were probably from the 1930s, judging by their appearance.?
My stock came back to me from my friend Brent, W1IA (SK), who had received them from me in 2006, when I moved. I got them from a co-worker in the 1980s, and they belonged to his dad, who was a TV repairman, so most of the parts are at least 37 years old. Other parts had been added over the years by Brent and me.?
Most of the parts look more ¡°modern¡± and most of those are still good, so far.?
Not all of the resistors in our Drakes have gone out of tolerance. The parts are affected by time, use, storage environment and other factors.?
I tend to only start measuring components when something is not working right or if I need to adjust a pot or cap to its extreme value. One could go crazy worrying about the parts, so we have to invest a certain amount of ¡°faith¡± that the parts inside are ¡°close enough¡±.?
73,
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 12:26, Bill Leonard N0CU < billincolo73@...> wrote: Steve, I agree. This is more of a temporary fix for me. Once I get everything working I will go back and replace them with new parts. What I don't remember is what is the drift profile of carbon comp resistors. Does continue indefinitely at a fairly constant rate or does it level off. If it is the latter, then I am not sure whether replacing them is necessary.
On Thu, Mar 16, 2023 at 9:56?AM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: The problem with that with respect to the cathode and screen resistors is that the out of tolerance parts will continue to drift out of tolerance. It¡¯s best to use new replacements of the original value.
73,
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 11:09 AM, Bill Leonard N0CU < billincolo73@...> wrote: 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: Sourcing T4Xany cathode and screen grid resistors
Steve, I agree. This is more of a temporary fix for me. Once I get everything working I will go back and replace them with new parts. What I don't remember?is what is the drift profile of carbon comp resistors. Does continue indefinitely at a fairly?constant rate or does it level off. If it is the latter, then I am not sure whether replacing them is necessary.
On Thu, Mar 16, 2023 at 9:56?AM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: The problem with that with respect to the cathode and screen resistors is that the out of tolerance parts will continue to drift out of tolerance. It¡¯s best to use new replacements of the original value.?
73,
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 11:09 AM, Bill Leonard N0CU < billincolo73@...> wrote: 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: DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
This is a standard sized wafer that has a quirky difference from a standard 2 pole 5 position wafer. The Common for one side is in the middle instead of at one end.
You get around this by drilling out the rivet on the common and of the terminal that is in the desired position for that common on a new standard wafer and repositioning it in the proper position. You replace the rivet with an 0-80 brass screw and nut. I use brass so that I can solder the nut permanently after tightening.
I have done this dozens of times with great results.
Gary
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On Mar 13, 2023, at 10:16 AM, Peter A <christinepeterarsenault@...> wrote:
and
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Re: TR7 Service Kit - Extender Boards Needed
Those are the boards that I have and they work very well.?
73,
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 11:07 AM, Mike Bryce < prosolar@...> wrote: 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: Need help with the planetary drive on T-4XC
That is also an advantage.?
Slightly OT, general purpose grease on the PTO bearings is what Drake used and its use also helped keep those 10 balls in place during reassembly.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
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On Thu, Mar 16, 2023 at 11:32 AM, Bill Leonard N0CU < billincolo73@...> wrote: 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: Sourcing T4Xany cathode and screen grid resistors
The problem with that with respect to the cathode and screen resistors is that the out of tolerance parts will continue to drift out of tolerance. It¡¯s best to use new replacements of the original value.?
73,
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 11:09 AM, Bill Leonard N0CU < billincolo73@...> wrote: 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
dave and the group,
finding .156 connectors are easy¡ªdigikey and mouser have them by the millions!
However, you need to know the series like KK or KW, KS, the pitch. Do you want locking tabs? What size pins? Male? Female? Surface mount or through hole? Let¡¯s not forget straight pins or 90? pins!
Go to
search for .156 connectors
That will drop down a menu list.
Select series type
Then mounting type
number of pin
and so on.
If you don¡¯t see what you need, simply back up and re-search.
Download the data sheets, too.?
good luck!
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
.com/
J e e p
o|||||||o?
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On Mar 16, 2023, at 11:41 AM, Dave Cutts via < g4faw@...> wrote:
Can anybody tell me where to get the .156 connectors from please? Thanks Dave G4FAW
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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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Doug Crompton WA3DSP
Gary WB6OGD
Jim Shorney