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Re: Another TR7 Journey begins
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 -Jim NU0C |
Re: SSB Audio
Thanks Gary! That makes me feel much better.? Will try it and let you know the?outcome.? Really appreciate the help! Mark On Thu, Feb 22, 2024 at 9:28?PM Gary WB6OGD <winbladgary@...> wrote:
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Mark "Fleisch" Fleischer KF?KZP Public Address Announcer/Voice Over/Production Specialist:? ,?,?, ,?,?,?(Superior), and?(Proctor) |
Re: RV-75 only decrements
开云体育If the frequency only changes up or down no matter which way you turn the knob one of the optical interrupters might be bad, misaligned, or the bias is not set correctly. ? From: [email protected] [mailto:[email protected]] On Behalf Of K6OXN Bob ? 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. |
Re: RV-75 only decrements
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. |
Re: SSB Audio
Mark, ? |
Re: RV-75 only decrements
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.
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Re: RV-75 only decrements
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. |
Re: RV-75 only decrements
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.??
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Re: Another TR7 Journey begins
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 |
Re: Another TR7 Journey begins
Keith Erickson
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On Feb 22, 2024, at 4:10?PM, Dale Parfitt <PARINC1@...> wrote:
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Re: Another TR7 Journey begins
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: |
Re: Another TR7 Journey begins
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, |
Re: Another TR7 Journey begins
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. |