I have some extra xtals. What bands are you looking for?
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On Mar 20, 2024, at 19:23, Mark KF0KZP <fleischtpnl@...> wrote:
?I have had good luck and have gotten quality/tested stuff from:??? ?Enjoy the C-Line I have a set and use and enjoy often!
KF0KZP
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I have had good luck and have gotten quality/tested stuff from:??? ?Enjoy the C-Line I have a set and use and enjoy often!
KF0KZP
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Hi all, Just picked up the Drake C-Line and would like to pick up crystals for general coverage and WARC bands who do I get them from? Any help would be appreciated! KG8FM? Ken?
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Re: Another TR7 Journey begins
I can¡¯t find any specs on the Tenma 72-460.? Tenma makes decent equipment, but the 72-460 may not be as sensitive as laboratory grade instruments from a variety of manufacturers, including HP. ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Bill NZ0T
Sent: Wednesday, March 20, 2024 6:28 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Another TR7 Journey begins ? The counter is a Tenma 72-460 that a friend lent me.? I do not know it's specs,? Yes the 10V is adjusted properly.??
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Re: Another TR7 Journey begins
The HP 5385A is a nice counter. It is essentially an updated version of the 5305B and is just a bit more sensitive at 15mV RMS vs 20mV. I have been using a 5305B, which was made in the mid '70's, for at least 15 years and it's still going strong. If it ever dies, I will probably get a 5385A.
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of jerry-KF6VB Sent: Wednesday, March 20, 2024 6:02 PM To: [email protected]Subject: Re: [DRAKE-RADIO] Another TR7 Journey begins On 2024-03-20 14:12, Omni wrote: less in some TR7¡¯s. You need a counter that can read a signal down
to at least 25mV RMS reliably, such as an HP 5316A/B, *** I scored an HP 5385A on Ebay specifically for this job. Sensitivity of 15mV RMS. I also have a cheap GPSDO for checking the counter. - Jerry, KF6VB
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Re: Another TR7 Journey begins
The counter is a Tenma 72-460 that a friend lent me.? I do not know it's specs,? Yes the 10V is adjusted properly.??
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Re: Another TR7 Journey begins
On 2024-03-20 14:12, Omni wrote: less in some TR7¡¯s. You need a counter that can read a signal down
to at least 25mV RMS reliably, such as an HP 5316A/B, *** I scored an HP 5385A on Ebay specifically for this job. Sensitivity of 15mV RMS. I also have a cheap GPSDO for checking the counter. - Jerry, KF6VB
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Re: TR7 - DR7 Display question
Excellent Jim, thanks very much.
73 de Raoul CE3RY
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Re: TR7 - DR7 Display question
No. Pin 8 is the common ground of all the buffers if the ULN2003 chip. You can test the LED segments by BRIEFLY grounding, one at a time, pins 10 through 16 of U9032. Doing so will illuminate the corresponding segment on all of the digits at once. You will want to do this quickly because this applies full drive to each LED. The display is strobed in normal operation so each digit is really only lit about 1/6 of the time. Having full drive applied for an extended amount of time could damage the LEDs. This will not harm the ULN2003 as it has open collector outputs. 73 -Jim NU0C On Wed, 20 Mar 2024 13:06:04 -0700 "Raoul Meunier" <rmeunier@...> wrote: Hi All,
I'm trying to repair a DR7 board and I would like to "turn on" all LED segments. From the diagram, I believe that grounding pin 8 of U9032 might do it. As I don't want to ruin anything on the card, please let me know your thoughts. Thanks.
73 de Raoul? CE3RY
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Re: Another TR7 Journey begins
Just a guess, but how sensitive is your counter.? The 5.645 MHz signal on Pin-40 is speced at 80mV P-P (57mV RMS) and is often quite a bit less in some TR7¡¯s.? You need a counter that can read a signal down to at least 25mV RMS reliably, such as an HP 5316A/B, or you will not get valid readings. ?The 5.645 MHz signal is adjusted with the PBT tuning turned on.? How do the fixed adjustments look in the various modes with the PBT off?? If you can¡¯t reliably set them either the counter may be the reason.? ? ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Bill NZ0T
Sent: Wednesday, March 20, 2024 4:16 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Another TR7 Journey begins ? I finally had a chance to use a decent frequency counter today. The 40 MHz oscillator is now spot on 40 MHZ and the VCXO is right on 53.695 MHz.? But the 8.05 MHz oscillator still will not quite get to 5.645 Mhz.? The closest I can get is 5.644534 MHz with C1030 nearly all the way in.? Is that "close enough"?? The answer is probably no but can't hurt to ask, right???
73, Bill NZ0T
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Re: R-4C Frying Egg/Static Noise
Hi Ed,
?
You want to start at the tail end of the R-4C.? Pull the last IF tube that is a pain to remove.? If the static does not go away, you know it is either the product
detector or the audio amplifier.? You could also turn the RF gain fully CCW, which mostly kills the gain of the last IF tube.
?
Let¡¯s assume the noise does go away, then the noise is in an earlier stage or that one 6BA6 is noisy.? The Sherwood solid-state third mixer is the next earlier
stage.? You could temporarily disconnect the 12 volts feeding the MIX-4.? If the noise goes away it means either the NE602A or the J309 is noisy, or that the noise in an earlier stage.? The NE602A is an a machined 8-pin socket so that is easy to swap out,
but I don¡¯t ever remember having to repair a noisy MIX-4.?
?
Let¡¯s assume for now that the MIX-4 is not the problem.? The next earlier stage is the 2nd mixer tube which is a 6BE6 if the S/N of the receiver
is 21,000 or higher.? That tube is not typically noisy, but it is possible.?? A 2N5950 drives the second mixer, which again is not typically noisy.?
?
All you have left is the 6EJ7 first mixer and the 6BA6 RF amplifier, plus the 6EJ7 pre-mixer.?? This all assumes S/N 21,000 and up.
?
Once I had a crackling noise from a leaky mica capacitor in the notch circuit, but a MIX-4 will removed B+ from those capacitors, so that isn¡¯t likely.
?
Let me know if this helps, and if not post again.
?
73, Rob, NC0B?
?
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From: [email protected] [mailto:[email protected]]
On Behalf Of Ed G
Sent: Wednesday, March 20, 2024 2:17 PM
To: [email protected]
Subject: [DRAKE-RADIO] R-4C Frying Egg/Static Noise
?
Folks,
???? I have a lot of the frying egg/static noise in my R-4C. I am using the Sherwood third mixer mod so don't have the usual suspect third mixer tube.? What else could be the source of that noise?
--Ed, N3CW--
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Re: Another TR7 Journey begins
True that, but he is following the alignment instructions in the service manual which has specific requirements. 73 -Jim NU0C On Wed, 20 Mar 2024 20:44:43 +0000 (UTC) "Bob Loving" <bob.loving@...> wrote: If I remember correctly, Bill, the frequency is dependent upon the mode of operation. The frequency shifts above or below the center 5.645000-MHz frequency of the various mode filters to place the carrier and BFO for proper USB, LSB, CW, and RTTY reception.
It has been a while since I've dealt with a TR7 so I may be blowing smoke. I apologize if that is the case.
73,Bob Loving K9JU
Maryville, TN
On Wednesday, March 20, 2024 at 04:15:55 PM EDT, Bill NZ0T <nz0tham@...> wrote:
I finally had a chance to use a decent frequency counter today. The 40 MHz oscillator is now spot on 40 MHZ and the VCXO is right on 53.695 MHz.? But the 8.05 MHz oscillator still will not quite get to 5.645 Mhz.? The closest I can get is 5.644534 MHz with C1030 nearly all the way in.? Is that "close enough"?? The answer is probably no but can't hurt to ask, right???
73, Bill NZ0T
-- 73 -Jim NU0C
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Re: Another TR7 Journey begins
Did you ensure that the +10 was adjusted spot on first? You may need to play with the value of C1029 a bit. That's why it is a factory selected value, it it compensates for variations in other components. Parts drift and crystals have tolerances. Try to use caps of the same temperature coefficient as the original C1029. 73 -Jim NU0C On Wed, 20 Mar 2024 13:15:50 -0700 "Bill NZ0T" <nz0tham@...> wrote: I finally had a chance to use a decent frequency counter today. The 40 MHz oscillator is now spot on 40 MHZ and the VCXO is right on 53.695 MHz.? But the 8.05 MHz oscillator still will not quite get to 5.645 Mhz.? The closest I can get is 5.644534 MHz with C1030 nearly all the way in.? Is that "close enough"?? The answer is probably no but can't hurt to ask, right?
73, Bill NZ0T
-- 73 -Jim NU0C
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Re: Another TR7 Journey begins
If I remember correctly, Bill, the frequency is dependent upon the mode of operation. The frequency shifts above or below the center 5.645000-MHz frequency of the various mode filters to place the carrier and BFO for proper USB, LSB, CW, and RTTY reception.
It has been a while since I've dealt with a TR7 so I may be blowing smoke. I apologize if that is the case.
73, Bob Loving K9JU
Maryville, TN
On Wednesday, March 20, 2024 at 04:15:55 PM EDT, Bill NZ0T <nz0tham@...> wrote:
I finally had a chance to use a decent frequency counter today. The 40 MHz oscillator is now spot on 40 MHZ and the VCXO is right on 53.695 MHz.? But the 8.05 MHz oscillator still will not quite get to 5.645 Mhz.? The closest I can get is 5.644534 MHz with C1030 nearly all the way in.? Is that "close enough"?? The answer is probably no but can't hurt to ask, right???
73, Bill NZ0T
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Re: R-4C Frying Egg/Static Noise
A bad/leaky power supply filter cap could be the culprit, especially in the +14v line. Is it there with no antenna connected? How about with volume at zero?
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On 3/20/2024 4:16 PM, Ed G wrote: Folks,
???? I have a lot of the frying egg/static noise in my R-4C. I am using the Sherwood third mixer mod so don't have the usual suspect third mixer tube.? What else could be the source of that noise?
--Ed, N3CW--
--
73 de Mike, W1NR
THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming!
- Ruk -
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Re: R-4C Frying Egg/Static Noise
I had a noisy V4, 6BA6, IF Amplifier.
Bob K9JU
On Wednesday, March 20, 2024 at 04:16:56 PM EDT, Ed G <ed.n3cw@...> wrote:
Folks,
???? I have a lot of the frying egg/static noise in my R-4C. I am using the Sherwood third mixer mod so don't have the usual suspect third mixer tube.? What else could be the source of that noise?
--Ed, N3CW--
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R-4C Frying Egg/Static Noise
Folks,
???? I have a lot of the frying egg/static noise in my R-4C. I am using the Sherwood third mixer mod so don't have the usual suspect third mixer tube.? What else could be the source of that noise?
--Ed, N3CW--
|
Re: Another TR7 Journey begins
I finally had a chance to use a decent frequency counter today. The 40 MHz oscillator is now spot on 40 MHZ and the VCXO is right on 53.695 MHz.? But the 8.05 MHz oscillator still will not quite get to 5.645 Mhz.? The closest I can get is 5.644534 MHz with C1030 nearly all the way in.? Is that "close enough"?? The answer is probably no but can't hurt to ask, right???
73, Bill NZ0T
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TR7 - DR7 Display question
Hi All,?
I'm trying to repair a DR7 board and I would like to "turn on" all LED segments.
From the diagram, I believe that grounding pin 8 of U9032 might do it. As I don't want to ruin anything on the card, please let me know your thoughts. Thanks.
73 de Raoul? CE3RY
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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.
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.
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
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