Hi Rick
Do you have the pushbutton in the TUNE position?? When I do (and with both fixed freq buttons OUT) the tuning on my RV75 is slower than the TR7 itself....I'd say maybe 10 degrees of knob motion for? 100 hz? change in the TR7 display
John K5MO
On Mon, Mar 13, 2023 at 1:23?PM Rick Boswell < frboswell@...> wrote: I began checking out a new-to-me RV75 this AM and am seeing some issues I dont yet understand. These are:
1. While the RV75 seems to be working in a basic fashion, the frequency displayed on the TR7 varies by as much a 2 KHz over time, even with an extneded warmup and without touching the tuning knob.
2. It is nearly impossible to set the frequenciny to the desired 100 Hz increment; very small movements of the tuning knob produce a few hundred Hz change in the displayed frequency.
3. The "Fixed Frequency" feature does not display the programmed frequency. Programming is a bit convoluted but I have verified several times that the switch settings are as described in the manual.
This is a a late serial number RV75 in very nice overall condition and was serviced by Ron Baker in 2015; his invoice shows only minimal work needed. My TR7 works as expected with an RV7 in place of the RV75.
So, wondering how best to proceed. Problems may be pilot error due to lack of familiarity, but if so, not clear what the pilot is doing wrong. I have a manual? but am reluctant to dive into troubleshooting without a better understanding as to what might cause these symptoms. Any guidance appreciated.
Rick
K8EZB?
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Re: Cinch Jones connector identification
Greg,
Thanks for your detaioled reply. I did find what looks like to correct connector on eBay.
Rick
K8EZB
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I began checking out a new-to-me RV75 this AM and am seeing some issues I dont yet understand. These are:
1. While the RV75 seems to be working in a basic fashion, the frequency displayed on the TR7 varies by as much a 2 KHz over time, even with an extneded warmup and without touching the tuning knob.
2. It is nearly impossible to set the frequenciny to the desired 100 Hz increment; very small movements of the tuning knob produce a few hundred Hz change in the displayed frequency.
3. The "Fixed Frequency" feature does not display the programmed frequency. Programming is a bit convoluted but I have verified several times that the switch settings are as described in the manual.
This is a a late serial number RV75 in very nice overall condition and was serviced by Ron Baker in 2015; his invoice shows only minimal work needed. My TR7 works as expected with an RV7 in place of the RV75.
So, wondering how best to proceed. Problems may be pilot error due to lack of familiarity, but if so, not clear what the pilot is doing wrong. I have a manual? but am reluctant to dive into troubleshooting without a better understanding as to what might cause these symptoms. Any guidance appreciated.
Rick
K8EZB?
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Hi Folks, Can anyone here write back and tell me the height of TR7 boards.? I am building sets of extender boards and need that dimension. Also, if there are technicians here willing to test my extender sets, please write back. Tu & 73 John WA1ESO@...401-624-4576
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Re: DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
Peter:
First...a small correction...not THE previous owner...but A previous owner.
Contact Paul Kramer, K0UYA, for his picture set on how he replaced that switch with a stripped down multiple section heavy duty 5 pos switch bought?on E-bay?cheaply from Eastern Europe.? I just checked?and there is a Bulgarian seller that seems to have several that would work,? You do need to make up a new shaft extender with the correct "flat" offsets - not too difficult.
Paul's address is; He will likely see this e-mail?anyways.
73 Peter VE7PS
There is a company on the east coast of ?the US that rebuilds switches. ? Not cheap though. ? Can't ?recall the name of the company.
-----Original Message-----
From: Peter A < christinepeterarsenault@...>
To: [email protected]
Sent: Mon, Mar 13, 2023 11:16 am
Subject: [DRAKE-RADIO] DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
[Edited Message Follows]
Hello to all.? It's been a minute since posting here but I keep up to date on what's up just the same.? Always interesting and informative.? This spring will be Delhi tower antenna erection, and hopefully get some of my Drake stuff on the air!? Difficulty deciding on a "multiband beam".? Either the Hy-gain TH-11DX or Optibeam OB9-HD5.? Anyway I'll figure it out eventually I guess.? Now to the point of this post.? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Wondering if anyone has an MN-2000? antenna switch?ceramic wafer they want to part with"? Previous owner "hot switched" and fried a few contacts.? I've removed the wafer over the weekend.? I tried the ebay seller " networkrw" and he was very hopeful he could help, but it didn't pan out as he couldn't find one close enough. Contacted Ron Wb4hfn but he said he didn't have that part.? Any ideas of where to source something suitable even with a little modification? I understand that a replacement was available from Russia but I doubt that's not an option at this point. I'd appreciate any info that may help.? I know about the direction of "drilling out" the rivets and swapping contacts with another wafer and using very small bolts to hold them in but is this the only option available, and I'm not even sure the contact plates would be good enough anyway?
I've looked at the older posts asking the same question but they're limited.
Any ideas would be greatly appreciated.
73
Peter
VE9KX
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Re: Puzzling problem with the AGC in my R4-C
Rob,
Thanks for sharing your insights on this.
What I think you are saying is that AGC attack distortion is a ¡°feature¡± of some of the designs in the receivers by Collins and Drake, and that this distortion increases as the decay time is reduced (which is what I am seeing). Also, the time constants used for the fast decays are off from what you recommend.
I don¡¯t operate CW so the distortion I am seeing with the M and F settings is not an operational issue for me. However, the engineer in me wants to fix the AGC if something is broken and it is not operating as designed. What I have concluded from your comments is that this is not the case.
What I failed to mention is that I have installed your NE602 product detector. I didn¡¯t mention it because I didn¡¯t suspect it could be a contributor to an AGC problem. So, did this detector mod eliminate the AGC attack distortion, or only reduce it.
As an aside, before I built and installed your NE602 product detector I tried a 1496 mixer circuit that I had laying around from a previous project. The conversion gain was so much lower than the original design that it was not a viable option.
-- Bill N0CU
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Re: DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
There is a company on the east coast of ?the US that rebuilds switches. ? Not cheap though. ? Can't ?recall the name of the company.
-----Original Message-----
From: Peter A <christinepeterarsenault@...>
To: [email protected]
Sent: Mon, Mar 13, 2023 11:16 am
Subject: [DRAKE-RADIO] DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
[Edited Message Follows]
Hello to all.? It's been a minute since posting here but I keep up to date on what's up just the same.? Always interesting and informative.? This spring will be Delhi tower antenna erection, and hopefully get some of my Drake stuff on the air!? Difficulty deciding on a "multiband beam".? Either the Hy-gain TH-11DX or Optibeam OB9-HD5.? Anyway I'll figure it out eventually I guess.? Now to the point of this post.? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Wondering if anyone has an MN-2000? antenna switch?ceramic wafer they want to part with"? Previous owner "hot switched" and fried a few contacts.? I've removed the wafer over the weekend.? I tried the ebay seller " networkrw" and he was very hopeful he could help, but it didn't pan out as he couldn't find one close enough. Contacted Ron Wb4hfn but he said he didn't have that part.? Any ideas of where to source something suitable even with a little modification? I understand that a replacement was available from Russia but I doubt that's not an option at this point. I'd appreciate any info that may help.? I know about the direction of "drilling out" the rivets and swapping contacts with another wafer and using very small bolts to hold them in but is this the only option available, and I'm not even sure the contact plates would be good enough anyway?
I've looked at the older posts asking the same question but they're limited.
Any ideas would be greatly appreciated.
73
Peter
VE9KX
|
Thanks Gregory. ?Without a pic, hard to know what a vendor is selling.
-----Original Message-----
From: Gregory Beat via groups.io <w9gb@...>
To: [email protected]
Sent: Mon, Mar 13, 2023 9:24 am
Subject: Re: [DRAKE-RADIO] DIN connectors
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DRAKE MN-2000 Ceramic wafer replacement/repair for Antenna Selector Switch help?
Hello to all.? It's been a minute since posting here but I keep up to date on what's up just the same.? Always interesting and informative.? This spring will be Delhi tower antenna erection, and hopefully get some of my Drake stuff on the air!? Difficulty deciding on a "multiband beam".? Either the Hy-gain TH-11DX or Optibeam OB9-HD5.? Anyway I'll figure it out eventually I guess.? Now to the point of this post.? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Wondering if anyone has an MN-2000?antenna switch?ceramic wafer they want to part with"? Previous owner "hot switched" and fried a few
contacts.? I've removed the wafer over the weekend.? I tried the ebay seller "networkrw" and he was very hopeful he could help, but it didn't pan out as he couldn't find one close enough.
Contacted Ron Wb4hfn but he said he didn't have that part.? Any ideas of where to source something suitable even with a little modification?
I understand that a replacement was available from Russia but I doubt that's not an option at this point.
I'd appreciate any info that may help.? I know about the direction of "drilling out" the rivets and swapping contacts with another wafer and using very small bolts to hold them in but is this the only option available, and I'm not even sure the contact plates would be good enough anyway?
I've looked at the older posts asking the same question but they're limited.
Any ideas would be greatly appreciated.
73
Peter
VE9KX
|
You can detune using a clip-lead jumper. Much safer and stable.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
Sent from Proton Mail for iOS
On Mon, Mar 13, 2023 at 01:59, Doug Crompton WA3DSP < wa3dsp@...> wrote: Somehow this discussion got off on measuring plate current, which makes no sense since there is already a means of checking cathode current using the two cathode resistors. In any case, my issue was definitely the shunt resistor, which had elevated to 9 ohms but physically looked OK! Replaced with three parallel 10 ohm 1/2 watt resistors and now get good cathode current readings.
The two cathode resistors in my unit had been changed to 10 ohm 2W and they measure very close to that and equal. Unfortunately, my brand-new tubes are not balanced, one has? .2 volts and the other .35 volts across their respective resistors or 20ma ans 35ma. I am going to check my stock for more 6JB6's and hopefully I can find a better match. How much of a difference is a problem? Also checked the screen resistors and they are closely matched so I don't think anyhing other than the tubes themselves would be causing the unbalance.
One problem I see is considerable power drop off on the higher bands. How much CW output should a good T4XC produce? I get 110W on 80 meters but down to about 60W or less on 40 and less even less on higher bands. I suspect the 12BY7 driver and I am going to look for one of them in my stock also. I have a 12.6mhz crystal but it apparently is not working as I get no drive on 160. Another thing to check.
Once I am confident that it is not a tube issue, I will do a complete alignment. I have a question about the RF and Mixer stage alignment procedure in section 5-8 of the manual. Item c-5 and c-6 refer to detuning by putting a screwdriver on the rotor. This seems like a weird way to do things. Has anyone come up with a better approach. Also, item c-5 says to tune the front injection trimmer, while item c-6 says to tune the rear injection trimmers - note plural. There are 4 trimmers, does that mean to tune the 3 rear trimmers? Perhaps someone has a better way of doing this?
Doug, WA3DSP
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Re: TR7 Service Kit - Extender Boards Needed
I found that the majority of problems was with the connectors on the mother board. Pull all boards and clean the connectors, dry joints were also a problem on both the mother board and the individual boards. The plug in co-ax board connectors can be a problem too. Best to do all this before fault finding on the individual boards. Hope this helps. 73 Dave G4FAW?
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As noted by?Garey Barrell, K4OAH (2015), the Switchcraft 3502
is a great RCA connector, with a variety of finishes (chrome to matte black)
greg, w9gb
chicago
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Re: Cinch Jones connector identification
Cinch Jones 300-series plugs Drake TR-7 transceiver (Rear Panel) has an 8-position Cinch Jones connector (308) for RV-7. The Accessories connector is a Jones 12-position connector (312). == Jones P-308-AB Plug is no longer being manufactured by Cinch (Obsolete), so requires looking thru distributor/surplus house inventory and maybe Beau/Molex offerings. Surplus Sales has this plug and proper backshell/hood to create that part (~ $10.50) You might need to fabricate locking pin for hood.
(CNE) P-308
Cinch Jones?8 pin plug. Add a? (CNE) 3308CCT?hood to complete an inline connector.
(CNE) 3308CCT
Cinch Jones?8 pin plastic backshell with clamp. Fits 308 plug or socket. 1"H x 1-1/4"W x 11/16"D.
==
Good Luck !
greg, w9gb
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DRAKE TECH NET ( March 12, 2023 )
Evan, K9SQG was the NCS for today's Drake Technical net on 7.238.? He had 39 check-ins under good band conditions.? Here are the radio's that were used to check-in.?
B Line 5 C Line 3 TR3 ?2 TR4 ?12 TR5 ?4 TR7 ?5 Other ?8
73's, Mark, WB0IQK
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See: /g/DRAKE-RADIO/message/5055573 -Jim NU0C On Sun, 12 Mar 2023 23:47:15 -0700 "Doug Crompton WA3DSP" <wa3dsp@...> wrote: Curious if Drake supplied RCA cables to connect the twins together. I count 6 sets. I have plenty of RCA cables from years of audio and video connections but I want to make a nice set specifically for the twins laced together and labeled. If Drake did include or sell them, what was the length? I have some real nice RG174 size Teflon coax and connectors that will make a nice set. I know the length is not particularly critical, but was just curious what was standard, if there was a standard.
Doug, WA3DSP
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Curious if Drake supplied RCA cables to connect the twins together. I count 6 sets. I have plenty of RCA cables from years of audio and video connections but I want to make a nice set specifically for the twins laced together and labeled. If Drake did include or sell them, what was the length? I have some real nice RG174 size Teflon coax and connectors that will make a nice set. I know the length is not particularly critical, but was just curious what was standard, if there was a standard.
?
Doug, WA3DSP
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Re: Puzzling problem with the AGC in my R4-C
The only time I ever used the FAST agc position, is when listening to AM signals, like SWBC.....esp on the 41 and 49m SWBC? bands...both of which can experience rapid, fast fades.?
What might make more sense is to use something like a 1 megohm pot and one cap. Then? (on paper) you should be able to tweak the agc from fast...to slow...and everything in-between.? It's just an RC time constant.?
?
What ever happened to ...'hang agc' ?? If you had a 90-200 msec? 'hang time', before the decay started, imo, it would sound a lot smoother, both on CW and also SSB.?
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Somehow this discussion got off on measuring plate current, which makes no sense since there is already a means of checking cathode current using the two cathode resistors. In any case, my issue was definitely the shunt resistor, which had elevated to 9 ohms but physically looked OK! Replaced with three parallel 10 ohm 1/2 watt resistors and now get good cathode current readings.
The two cathode resistors in my unit had been changed to 10 ohm 2W and they measure very close to that and equal. Unfortunately, my brand-new tubes are not balanced, one has? .2 volts and the other .35 volts across their respective resistors or 20ma ans 35ma. I am going to check my stock for more 6JB6's and hopefully I can find a better match. How much of a difference is a problem? Also checked the screen resistors and they are closely matched so I don't think anyhing other than the tubes themselves would be causing the unbalance.
One problem I see is considerable power drop off on the higher bands. How much CW output should a good T4XC produce? I get 110W on 80 meters but down to about 60W or less on 40 and less even less on higher bands. I suspect the 12BY7 driver and I am going to look for one of them in my stock also. I have a 12.6mhz crystal but it apparently is not working as I get no drive on 160. Another thing to check.
Once I am confident that it is not a tube issue, I will do a complete alignment. I have a question about the RF and Mixer stage alignment procedure in section 5-8 of the manual. Item c-5 and c-6 refer to detuning by putting a screwdriver on the rotor. This seems like a weird way to do things. Has anyone come up with a better approach. Also, item c-5 says to tune the front injection trimmer, while item c-6 says to tune the rear injection trimmers - note plural. There are 4 trimmers, does that mean to tune the 3 rear trimmers? Perhaps someone has a better way of doing this?
Doug, WA3DSP
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My memory isn't good enough to give specifics but I do remember that there are different DIN connectors that retain the same designation. ?As I vaguely recall, it might be 4, 5, pin styles. While they might have the same number ?of pins, they may not have identical arrangements. ?This can make connector selection confusing.
Please send flames off list.
73,
Evan, K9SQG
-----Original Message-----
From: Gregory Beat via groups.io <w9gb@...>
To: [email protected]
Sent: Sun, Mar 12, 2023 1:12 pm
Subject: Re: [DRAKE-RADIO] DIN connectors
The Metal Body circular DIN connectors exist,
BUT typical hobbyist & radio amateur will Constantly Complain about PRICE.
DELTRON COMPONENTS (North Lincolnshire, UK)
SWITCHCRAFT/CONXALL (Chicago area, USA)
DIN CABLE MOUNT
greg, w9gb
Conxall (military) division is in my neighborhood
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Greg W9GB
Jim Shorney
Doug Crompton WA3DSP