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Re: One last call for Help..T-4XB
I don't have the schematic here, but sometimes when I've had audio bleeding onto circuits where it did not belong, I found that the power line into the audio source stage had a bypass capacitor fail (go low in value with age).? It was letting audio ride on the B+ power backwards out of the audio source stage.? The audio was then able to get into another stage and be heard there (bypassing whatever was the normal switching or muting scheme).
73?? Steve? WD8DAS
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Re: One last call for Help..T-4XB
He is more selective and I can fully understand that.? I'm still working on these rigs but I'll be on hiatus until August.? I'm clearing out what I have now so that I can take June and July off.? When I'm back, I will be limiting myself to unmodified rigs, only.? I have seen too many rigs (especially R-4C's) that "have all the mods, and they're great!" only to find out they were made by hand from junkbox parts and soldered-in with a Bernz-O-Matic torch.
Sidetone bleed-through can arise from other capacitors being bad or gassy tube(s). Check around V9, including the electrolytic cap, and D7.
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Wednesday, January 31st, 2024 at 6:36 PM, Richard WB3AVF <ague@...> wrote:
I just had my TR-4C worked on and received it from Ron in December 2023. On Jan 31, 2024, at 6:05?PM, Ed KG5UN <maikranze@...> wrote:
? I think he is a little selective on what he works on these days but still very much in business. I emailed hime?a couple of weeks ago about working on a B-line, a C-line and a 7 line and he said to send them on up to him.
Ed KG5UN
Tim, I was under the impression that Ron retired from Drake repair about a year ago. Can anyone confirm or deny that?
73, Mike KE5YTV
On Wednesday, January 31, 2024 at 03:08:24 PM CST, Tim Randa < randaranch@...> wrote:
One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic. I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue.
?
Any ideas you can send my way would be appreciated?greatly
?
73 de Tim? K?FL
Kansas
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Re: One last call for Help..T-4XB
I just had my TR-4C worked on and received it from Ron in December 2023.
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On Jan 31, 2024, at 6:05?PM, Ed KG5UN <maikranze@...> wrote:
? I think he is a little selective on what he works on these days but still very much in business. I emailed hime?a couple of weeks ago about working on a B-line, a C-line and a 7 line and he said to send them on up to him.
Ed KG5UN
Tim, I was under the impression that Ron retired from Drake repair about a year ago. Can anyone confirm or deny that?
73, Mike KE5YTV
On Wednesday, January 31, 2024 at 03:08:24 PM CST, Tim Randa < randaranch@...> wrote:
One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic. I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue.
?
Any ideas you can send my way would be appreciated?greatly
?
73 de Tim? K?FL
Kansas
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Re: One last call for Help..T-4XB
I think he is a little selective on what he works on these days but still very much in business. I emailed hime?a couple of weeks ago about working on a B-line, a C-line and a 7 line and he said to send them on up to him.
Ed KG5UN
Tim, I was under the impression that Ron retired from Drake repair about a year ago. Can anyone confirm or deny that?
73, Mike KE5YTV
On Wednesday, January 31, 2024 at 03:08:24 PM CST, Tim Randa < randaranch@...> wrote:
One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic. I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue.
?
Any ideas you can send my way would be appreciated?greatly
?
73 de Tim? K?FL
Kansas
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Re: One last call for Help..T-4XB
Believe it was WA8SAJ who retired¡ ? ?
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From: [email protected] < [email protected]> On Behalf Of Mike Bracey Sent: Wednesday, January 31, 2024 5:24 PM To: [email protected]Subject: Re: [DRAKE-RADIO] One last call for Help..T-4XB ? Tim, I was under the impression that Ron retired from Drake repair about a year ago. Can anyone confirm or deny that? On Wednesday, January 31, 2024 at 03:08:24 PM CST, Tim Randa <randaranch@...> wrote: One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic.
I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue. Any ideas you can send my way would be appreciated?greatly
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Re: One last call for Help..T-4XB
Tim, I was under the impression that Ron retired from Drake repair about a year ago. Can anyone confirm or deny that?
73, Mike KE5YTV
On Wednesday, January 31, 2024 at 03:08:24 PM CST, Tim Randa <randaranch@...> wrote:
One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic. I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue.
?
Any ideas you can send my way would be appreciated?greatly
?
73 de Tim? K?FL
Kansas
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One last call for Help..T-4XB
One last request for ideas before shipping my T-4XB off to guru Ron Baker for his magic. I suddenly had what seems to be sidetone bleed through. When the radio is keyed in cw mode there is a constant fuzzy tone. When you press the cw key the actual sidetone is heard above the volume level of the bleed through but the background buzz/tone is always present. This does not happen in ssb mode. I had hoped replacing a possible gassy 6EV7 tube might fix it but no luck. Years ago I had installed the hayseed capacitor?can in a different set of B's but just can't remember if that was for this issue or not. The twins just aren't usable for me with this issue.
?
Any ideas you can send my way would be appreciated?greatly
?
73 de Tim? K?FL
Kansas
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I need a power transformer for a Drake 2-NT transmitter.
Roger, k9vp
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On Mon, Jan 29, 2024 at 11:31 PM, Joe Pyles wrote:
even though the capacitance was in spec the ESR was way off
In quickly checking ESR today I noticed this in at least one instance. All new caps ordered per Jim's parts list. Jim: Thanks for making this so easy: go to Mouser website, enter PN's & quantity, checkout. In looking more carefully at the 10K resistor described by Peter (aka Steve) as "broken," that description appears to be accurate on close inspection. I see no evidence of burning on the resistror body or PC board. How this would come to be broken and positioned as I found it is not at all clear, except by human intervention. This resiistor does not appear on my manual ckt diagram. OTOH, the 150 ohm resistor shows very clear evidence of burning on both the resistor body and PC board. This resistor connects to the "Enable" line via the RV75 to TR7 cable and appears to bias the PIN diode on to enable RF output. A quick check of the PIN diode seems to indicate it is OK. I'll need to look at the TR7 ckts to better understand how this is supposed to work. I have spent considerable time visually inspecting both boards and see no obvious physical problems beyond the failed resistors. There is some evidence of rework around two DIP IC's on the digital board, but this may have been done by Drake on the production line. My current plan is to replace the defective resistors and any caps where the value or ESR is out of line. I'll also investigate the "Enable " line back into the TR7. Once this is done I dont see that I can go much farther without reassembling the RV75 and powering it up with the TR7. RB
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I have 2 RV75 VFOs and on both of them I started hearing strange noises when tuning across a signal. This was very noticeable on AM. The internal PTO did not make the noises. I put a scope on the voltage rails and there was all kinds of noise on them. I started removing the electrolytics 1 at a time and even though the capacitance was in spec the ESR was way off. So I replaced all of the electrolytics and the noise on the DC voltage rail was gone and the noise when tuning across signal was gone. They both have been regular use for the last 5 years with no more problems.
73, Joe Pyles KC9LAD
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At 10:53 PM 1/29/2024, you wrote: There is a method to my madness. Sub standard or failing capacitors can cause all sorts of strange problems. The RV75 was released in 1982. That's over 40 years ago.
73
-Jim
NU0C
On Mon, 29 Jan 2024 15:34:43 -0800
"Rick K8EZB" <frboswell@...> wrote:
Just replace them.
I'll get to this but first trying to do a top level assessment of
what the problem might be. Since the caps seem OK for now, I'll look for other possible causes first. My approach is to attempt to get this gear limping along and then tidy up the seconday issues. So far I have only about an hour of time into this, and am seeing all this for the first time; still much to learn. Per your suggestions, going slow and taking plenty of pictures!
Thanks for your response.
RB
--
73
-Jim
NU0C
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There is a method to my madness. Sub standard or failing capacitors can cause all sorts of strange problems. The RV75 was released in 1982. That's over 40 years ago. 73 -Jim NU0C On Mon, 29 Jan 2024 15:34:43 -0800 "Rick K8EZB" <frboswell@...> wrote:
Just replace them.
I'll get to this but first trying to do a top level assessment of what the problem might be. Since the caps seem OK for now, I'll look for other possible causes first. My approach is to attempt to get this gear limping along and then tidy up the seconday issues. So far I have only about an hour of time into this, and am seeing all this for the first time; still much to learn. Per your suggestions, going slow and taking plenty of pictures!
Thanks for your response.
RB
-- 73 -Jim NU0C
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On Mon, Jan 29, 2024 at 03:59 PM, John K5MO wrote:
"Fixing" too much stuff at once can inject additional problems into the mix ,often masking the initial problem !
Been there, done that too! I wont plug in the soldering iron until I have a strong conviction as to what the problem is.? RB
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Re: Looking for a working Drake T4X
David, W5XU,
I just sent you an email.
Thanks,
Kevin W2TVS
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RB
That's a wise strategy.? "Fixing" too much stuff at once can inject additional problems into the mix ,often masking the initial problem !
I'm sensitive to this behavior as I've done it multiple times myself...? :-)
John K5MO
On Mon, Jan 29, 2024 at 6:34?PM Rick K8EZB < frboswell@...> wrote: Just replace them.
I'll get to this but first trying to do a top level assessment of what the problem might be. Since the caps seem OK for now, I'll look for other possible causes first. My approach is to attempt to get this gear limping along and then tidy up the seconday issues. So far I have only about an hour of time into this, and am seeing all this for the first time; still much to learn. Per your suggestions, going slow and taking plenty of pictures!
Thanks for your response.
RB
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Re: R4B loose wire on board 8 (crystal calibrator)
Thank you for your thoughts! I believe the calibrator is behaving, I'll need to double check.
Make sense that someone attached the wire as a reference point for a scope.
Joe.
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Re: R4B loose wire on board 8 (crystal calibrator)
Joe,
Its out of place as you say!
My guess is its leftover from a previous debugging session, just an easy ground point to attach the scope probe.
The ICs on the cal board are obsolete, probably because they were pretty un-reliable.? I had a caibrator problem
with my R-4B too, think it was a cold solder joint but I can't recall exactly (not an IC problem).
73,
Gary
WB6OGD
?
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Just replace them.
I'll get to this but first trying to do a top level assessment of what the problem might be. Since the caps seem OK for now, I'll look for other possible causes first. My approach is to attempt to get this gear limping along and then tidy up the seconday issues. So far I have only about an hour of time into this, and am seeing all this for the first time; still much to learn. Per your suggestions, going slow and taking plenty of pictures! Thanks for your response. RB
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R4B loose wire on board 8 (crystal calibrator)
Good day, I have the R4B out of the cage getting ready to replace the electrolytic capacitors. I was looking around for anything out of place before I got started. Upon inspection, I saw a red wire that is soldered to the crystal calibrator board #8 that is not attached on the other end. I've attached two images. One is from my R4B, and the other is from the K4OAH CD. I don't see the same red wire on Garey's image, so I'm scratching my head a bit over here. The red wire in my image is soldered to the chasis grounded perimeter trace of the board that is connected to the ground screws.? Any thoughts on this? I'm attaching two images. One from Garey's CD, and the other is from my R4B. Thanks! Joe ki5o  
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Ronnie Hull - W5SUM
Ed KG5UN
Joseph K4JNG
Jim Shorney
Kevin W2TVS
Gary WB6OGD