The one you really want is the "Jumper" board. It is by far the one I have used the most. It allows you to do tests on the radio without the DR7 installed. I rarely use any of the other extenders.

Here is what the original Drake extenders look like:



73

-Jim
NU0C

On Mon, 13 Mar 2023 09:49:17 -0700
"JP Nery via groups.io" <jpnery@...> wrote:

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

On Mon, 13 Mar 2023, Lyndon Nerenberg (VE7TFX/VE6BBM) wrote:

Gee, Richard, you could just box it up and send it back to me :-)

I could do that but where would you put yet more radios? And the postage
would knock another hole in your bank account.
--
Richard Loken VE6BSV : "...underneath those tuques we wear,
Athabasca, Alberta Canada : our heads are naked!"
** rlloken@... ** : - Arthur Black

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Here is link to pictures of the switch.? Wish they were better pictures but that is all I have.? Ignore the paint finish pictures at end.? I also refinished the cabinet.

Paul K0UYA

?Paul Kraemer 5:56pm???#69934??? Peter et al I got the message(s) and I can help with that switch replacement.? I was able to find an inexpensive switch on ebay and "adapt" it to repair the MN200 to "better than new".? The switch is basically Soviet or Eastern Europe manufacture, rugged, fits same space.? The only mod to the switch is remove extra wafers from the back end and mount it backwards in the tuner.? You can cut the switch shaft short or leave it to protrude through the rear panel.? A shaft coupling is used to mate the Drake selector knob shaft extension to the new switch.? Both the switch shaft and the selector shaft are flatted and do not line up.? To ensure a sturdy coupling you need to drill a new set screw hole in the coupling to compensate for the alignment.? That makes the set screws land on the flatted shafts.? I made my own coupling from a short piece of 1/2" dia aluminum rod.? EASY and it stays indexed even if the screws are loose. The Drake switch had back to back contacts on a single wafer.? The new switch I used two wafers wired together.. If the switch can't be found on ebay I have an extra. I 'll find the picture file and hopefully someone can put them on the reflector archives. IT IS A NICE REPAIR---NO KLUDGE. Paul K0UYA Paul, that sounds fantastic.? Anyhow, I like a challenge so wouldn't want an exact replacement anyway.? HIHI.? If you remember the ebay seller that'd be helpful also. appreciate everything. Thank you Paul. Peter VE9KX

Richard Loken writes:

I also have a C line but that is a waste since I have all the skill and
ambition of the Saksatchewan farmers I knew as a schoolboy who parked their
Galaxy Vs on 3785kHz and chatted to their friends down the road every night.

Gee, Richard, you could just box it up and send it back to me :-)

--lyndon

I have experienced dirty pushbuttons and small electrolytics that failed miserably in my RV75. They were Capar branded. If you have those replace them.

73

-Jim
NU0C

On Mon, 13 Mar 2023 10:23:47 -0700
"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

On Mon, Mar 13, 2023 at 06:06 PM, John K5MO wrote:

I was prepared to do just that John, meaning drill the rivets, replace contacts from another wafer but I think the actual contact plates themselves are a bit rough.
Peter
VE9KX

开云体育

Peter et al

I got the message(s) and I can help with that switch replacement.? I was able to find an inexpensive switch on ebay and "adapt" it to repair the MN200 to "better than new".? The switch is basically Soviet or Eastern Europe manufacture, rugged, fits same space.? The only mod to the switch is remove extra wafers from the back end and mount it backwards in the tuner.? You can cut the switch shaft short or leave it to protrude through the rear panel.? A shaft coupling is used to mate the Drake selector knob shaft extension to the new switch.? Both the switch shaft and the selector shaft are flatted and do not line up.? To ensure a sturdy coupling you need to drill a new set screw hole in the coupling to compensate for the alignment.? That makes the set screws land on the flatted shafts.? I made my own coupling from a short piece of 1/2" dia aluminum rod.? EASY and it stays indexed even if the screws are loose.

The Drake switch had back to back contacts on a single wafer.? The new switch I used two wafers wired together..

If the switch can't be found on ebay I have an extra.

I 'll find the picture file and hopefully someone can put them on the reflector archives.

IT IS A NICE REPAIR---NO KLUDGE.

Paul K0UYA

On Mon, 13 Mar 2023, Rob Sherwood wrote:

The major change was 8-pole TX filters instead of 4 pole. Then the T-4XC came out with "locked transceive" which had never existed previously. (Meaning there was not an RX vs. TX frequency error.) Rob, NC0B

Well that is interesting. That explains why a casual glance at the
photographs on eBay do not show any differences.

I have a T4XB so, by your desription, it is the better bargain.

I also have a C line but that is a waste since I have all the skill and ambition of the Saksatchewan farmers I knew as a schoolboy who parked their Galaxy Vs on 3785kHz and chatted to their friends down the road every night.
--
Richard Loken VE6BSV : "...underneath those tuques we wear,
Athabasca, Alberta Canada : our heads are naked!"
** rlloken@... ** : - Arthur Black

On Mon, Mar 13, 2023 at 04:53 PM, n4buq wrote:

Isn't that just a ceramic Centralab wafer?? Those can often be found as individual wafers on eBay, etc., with the correct shaft hole and contacts/wiper configuration.? The trick is getting the proper stud spacing.? I had to replace a few of those in a VTVM last year and it took a while to find a proper replacements but I finally found them.

?

Good luck with it.

I do believe it is one of their wafers but difficult to find the exact.
I was in touch with an Ebay seller who sells this type of thing and in all his inventory he had no match.
Thanks for the input Barry.
73
Peter
VE9KX

?

?

Thanks,
Barry - N4BUQ

?

---

From: "Peter A" <christinepeterarsenault@...>
To: "DRAKE-RADIO" <[email protected]>
Sent: Monday, March 13, 2023 10:16:32 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

The major change was 8-pole TX filters instead of 4 pole. Then the T-4XC came out with "locked transceive" which had never existed previously. (Meaning there was not an RX vs. TX frequency error.) Rob, NC0B

开云体育

On Mon, Mar 13, 2023 at 12:51 PM, VE7PS wrote:

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;

elespe@...

He will likely see this e-mail?anyways.

?

73

Peter

VE7PS

For sure Peter!!? Thanks for the correction.? I worded that wrong.
I'll contact Paul and ask for some guidance on that.
I do have alternatives now to this unit but I don't want to part it out because of the antenna switch alone.
Thanks for the tip.
73
Peter
VE9KX

?

The subject says it all: what did Drake change when they went from the
T4X and the T4XB? Was there a T4XA?
--
Richard Loken VE6BSV : "...underneath those tuques we wear,
Athabasca, Alberta Canada : our heads are naked!"
** rlloken@... ** : - Arthur Black

On Mon, Mar 13, 2023 at 10:46 AM, John K5MO wrote:

Do you have the pushbutton in the TUNE position?

Yes, with both Fixed Feq buttopns out.

RB