Is it acceptable to advertise a TR7 for sale on this group? Thanks Dave G4FAW?

OK, here is what I would do. First, thoroughly inspect the area of the oscillator circuit with a magnifier and good lighting. Look for suspicious solder joints (especially where a connection is made through a plated through hole, a.k.a. VIA), copper trace breaks, hairline shorts, etc. Clean any flux residue you might find. Take the piston trimmer apart to see if you can figure out why it is binding. There is no advanced phlebotinum or magic server pixie dust inside, it is just cleverly made from common materials. You could probably make one with materials from Ace Hardware. Or find a replacement that is close in value and about the same physical size or smaller and adapt it to fit. It is only two electrical connections.

We learn. 35 years ago the TR7 scared the hell out of me. After a lot of tinkering and a few mistakes I understand it pretty well. In the end it's just a radio, made out of dirty sand and carbon. And it is user serviceable.

73

-Jim
NU0C

On Thu, 22 Feb 2024 15:31:51 -0800
"Bill NZ0T" <nz0tham@...> wrote:

Jim I understand but not all of us have your expertise and sometimes just want to the radio working lol.? I had no trouble at all with the 20 WPM part fo the old Extra test but the theory was a big time struggle for me.? Sometimes I can muddle along and fix something but I'm a horrible tech.

73, Bill NZ0T

--

73

-Jim
NU0C

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I'm seeing mixed messages from you. First it only decrements, then it the direction it tunes is opposite what you expect, now it only decrements again? Which is it?

Did you perform the checks here?: /g/DRAKE-RADIO/message/76205

If so, what did you see?

If not, do so and report back what you find. That will help narrow down the issue. What you have reported so far is roughly the radio equivalent of "my car is making a funny noise, what's wrong with it?" At this point the only answer that can be given is "It's broken".

73

-Jim
NU0C


On Thu, 22 Feb 2024 19:20:15 -0800
"K6OXN Bob" <bobk6oxn@...> wrote:

Well I have checked all the frequencies used for a ref in the rv-75. When I turn it on with 7 mhz selected, I get 7250.1 all bands check out like this. I cannot get it to increase in freq only decrease whichever way I turn the knob. I am at my wits end with this for now. Will place it on back of bench for awhile.? All voltage ref's are good or within spec.

Mark,
Forget the new radio and just look at the TR-4.

Use the calibrator and adjust the dial so? the calibrator is zero beat and the dial reads 21.300.

Now, you are receiving exactly on 21.300.? In USB and LSB your are transmitting on exactly 21.300.

If you now go to CW or AM, the carrier is offset from 14.300 by probably the 895Hz so you are transmitting on 21.300.895.
This is done for the dual purpose that the carrier needs to go through the crystal filter and for CW you need to tune off off zero beat to hear received signals.

Your TR-4 is normal.
73,
Gary
WB6OGD

?

Well I have checked all the frequencies used for a ref in the rv-75. When I turn it on with 7 mhz selected, I get 7250.1 all bands check out like this. I cannot get it to increase in freq only decrease whichever way I turn the knob. I am at my wits end with this for now. Will place it on back of bench for awhile.? All voltage ref's are good or within spec.

This is an option, not a problem. See page 2-2 of the manual, re: J-104.

73

-Jim
NU0C

On Thu, 22 Feb 2024 16:41:07 -0800
"K6OXN Bob" <bobk6oxn@...> wrote:

Well after replacing all the electrolytics the 75 seems to work somewhat.? Freq is stable, but if I turn the knob CCW the freq increases and if I turn it CW it decreases. So what do I look at for this problem. I can adjust all the freq's listed in section 5 but I don't know about the reversal. Maybe I have the Optical drive connectors on wrong.? Will look at that next. Otherwise it seems to work.

Well after replacing all the electrolytics the 75 seems to work somewhat.? Freq is stable, but if I turn the knob CCW the freq increases and if I turn it CW it decreases. So what do I look at for this problem. I can adjust all the freq's listed in section 5 but I don't know about the reversal. Maybe I have the Optical drive connectors on wrong.? Will look at that next. Otherwise it seems to work.??

Jim I understand but not all of us have your expertise and sometimes just want to the radio working lol.? I had no trouble at all with the 20 WPM part fo the old Extra test but the theory was a big time struggle for me.? Sometimes I can muddle along and fix something but I'm a horrible tech.

73, Bill NZ0T

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Agreed, several times here also. ?

Years ago I picked up a 104A to flip. Then I learned this. I still have it. I corresponded with Mike a few times before he went SK. A fine gentleman.

73

-Jim
NU0C

On Thu, 22 Feb 2024 14:25:38 -0800
"Bill NZ0T" <nz0tham@...> wrote:

Found this from the Drake Forum:

The development of the TR-7 transceiver was the first attempt of the Drake engineers, basically tube guys, switching to all solid state, went through a lot of pain-taking trials and errors. Drake convinced a young engineer, Mike Elliott, to come to work for Drake to help with the TR-7 design. At that time Mike worked for Heathkit and was the designer of the Heathkit SB-104, the first all solid state transceiver ever built. Mike Elliott's engineering and design background was very instrumental it the design of the TR-7 radio. The most unusual design innovation of the TR-7 was the use of a very high IF frequency. Using 48.05 Mhz IF frequency eliminated most the birdies, whistles and squawks that popped up on the tuning dials commonly found in most radios of that era.

Personally I prefer to repair them. Generally I don't like to encourage those that cut up perfectly good radios for profit. In the CSIPH newsgroup we had a fellow that called then "tin men". But that's a whole different discussion. I'm also a capitalist. I get it. But I also repair things that are repairable. That includes "broken" boards that others throw out. I think it is hip these days to call that recycling.

73

-Jim
NU0C

On Thu, 22 Feb 2024 13:32:13 -0800
"Bill NZ0T" <nz0tham@...> wrote:

Jim,

I totally understand the issues that can come with a "pull" board.? I have used them before with other rigs and for the most part they soved the problem or at least gave me a source of parts to repair the original board.? The first time I did so was to repair a Heathkit SB-104A which was designed by the same engineer who later designed the Drake 7 series and had the same type of vertical removable boards.

73, Bill NZ0T

Kevin,

Yeah, I know that. But I thought maybe someone might like to have the original printed version.??

73, Bill NZ0T

Found this from the Drake Forum:

The development of the TR-7 transceiver was the first attempt of the Drake engineers, basically tube guys, switching to all solid state, went through a lot of pain-taking trials and errors. Drake convinced a young engineer, Mike Elliott, to come to work for Drake to help with the TR-7 design. At that time Mike worked for Heathkit and was the designer of the Heathkit SB-104, the first all solid state transceiver ever built. Mike Elliott's engineering and design background was very instrumental it the design of the TR-7 radio. The most unusual design innovation of the TR-7 was the use of a very high IF frequency. Using 48.05 Mhz IF frequency eliminated most the birdies, whistles and squawks that popped up on the tuning dials commonly found in most radios of that era.

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Or they can download the R8 and R8e here http://ftb.ko4bb.com/getsimple/index.php?id=manuals&dir=05_Misc_Ham_Equipment/Drake

On 2024-02-22 13:32, Bill NZ0T wrote:

SB-104A which was designed by the same engineer who later designed the
Drake 7 series

*** Interesting. I wonder if he was a Collins engineer? I heard somewhere
that Heath poached some Collins people to design their "poor man's S-line".

- Jerry, KF6VB