One of "THOSE" weekends....

[W1GUH]

When hardly anything cooperated and insisted on being as obtuse and difficult as possible. Argh!!!

TR-7 is proving to be fussy. Well, not really, but I do need to go through it and give a complete alignment and check-out. And it's probably not bad contacts anymore -- I did all the cards on the mother board & it's still flaky.

At least I've got another clue. Used to have an intermittent "no transmit audio" glitch that would come and go - but the vox was always OK. This weekend it also developed a "no product detector output" glitch. Maybe related? Yes! Will be digging into the Service manual.

And, btw, TR-7's don't like to get cold. Left it out in the car Fri. night and it took a good long time for it to get warm enough to work OK. Won't do that again!

[K7SGJ]

Might be a loose nut hanging on the mic. No?

[W1GUH]

That's always the case! Radio mods are to deal with that!

[W7XF]

Might be a loose nut hanging on in front of the mic. No?

Fixed!! :rofl:

[N8YX]

At least I've got another clue. Used to have an intermittent "no transmit audio" glitch that would come and go - but the vox was always OK. This weekend it also developed a "no product detector output" glitch. Maybe related? Yes! Will be digging into the Service manual.


2nd IF/Detector board - loose or cold solder joint on one of the Molex edge connectors. Remember that I discussed this once before? The tin plating on the contact's base metal separates from said metal through galvanic action and oxidation. It's a known problem.

I have half a dozen of those boards around here and could send you one...but I'll bet a resolder job will fix things.

[W1GUH]

Thanks.

[N8YX]

I'll send a board out if you need it. Also have most of the semis needed to repair the later versions, including the MC1496.

[WØTKX]

Is that the only HF rig you have Paul?

[W1GUH]

No....

The list....


FT-817*
FT-857*
IC-720a*
TR-3*
G-76
Cheyenne/Comanche
AF-67 rx Gonset Super-12
FT-TH6*

The ones marked with an asterix...er...asterisk have been on the air in the car.

Why do you ask?

[WØTKX]

I wasn't sure, and it's extra annoying to have a radio get flaky if you only have one. ;)

[W1GUH]

Even more irritating when you forget the back-up! Usually the '857's along just in case. This time I clean forgot it. OTOH...I like the '7 SO MUCH, that even with a non-functional tx & can only receive AM, I was having a ball with it SWL'ing & listening to some AM'ers on 40 and thinking of the day when I've got the G-76 going with AM audio up to the window's de facto standards.

[edit]
Don't know what the rx in the Gonset sounds like yet -- could be that the '7 turns out to be the AM rx. In that case, it'll probably be the AF-67 in the car.

But first, I've got a TR-7 to restore!

[W1GUH]

I'll send a board out if you need it. Also have most of the semis needed to repair the later versions, including the MC1496.

Thanks for the offer! I'll let you know what I find & if I need any parts or anything.

[W1GUH]

2nd IF/Detector board - loose or cold solder joint on one of the Molex edge connectors. Remember that I discussed this once before? The tin plating on the contact's base metal separates from said metal through galvanic action and oxidation. It's a known problem.

I have half a dozen of those boards around here and could send you one...but I'll bet a resolder job will fix things.

Doing that right now. Here's hoping. Trouble is, the intermittent nature of the bug means that even if I do it, and it's OK on the bench, that doesn't really mean it's fixed. But this is a must to do regardless, so here goes.

[N8YX]

Let us know what you find. I also have the service manual on-hand and will be glad to take a further look.

[W1GUH]

Re-soldered all those molex connections & didn't fix it. Well, it needed to be done anyway.

[N8YX]

Re-soldered all those molex connections & didn't fix it. Well, it needed to be done anyway.
Do the ones on the parent board as well?

[N8YX]

At least I've got another clue. Used to have an intermittent "no transmit audio" glitch that would come and go - but the vox was always OK. This weekend it also developed a "no product detector output" glitch. Maybe related? Yes! Will be digging into the Service manual.

Transmit Exciter Board - U301 - an MC3302 quad op amp, located on the other end of the board from the 1496. There's your commonality - it affects ALL TX audio circuits...mic, VOX and anti-trip/PTT activation.

Cold solder joint is a possibility.

ETA:

When I directed you to check the IF board connections, it slipped my mind that - unlike a number of other designs - the TR7 uses a separate exciter board for generation of the DSB signal.

[W1GUH]

It's really time to get out the 'scope & start looking at signals under the hood. Cleaning contacts, while necessary and needed, isn't going to pinpoint what's going on & I'd much rather find the specific problem(s) via testing and then do what's needed to fix it orthose. I'm pretty sure I've seen links to people selling extender boards, or at least I sure hope so. This could be a real bitch without those.

Thanks for your help...but it's time to do it the "hard way!" (Check that...the "fun way!")

[W1GUH]

Looks like I found one....W7AVK's kit (http://www.wb4hfn.com/Services/W7AVK/tr7ext2.htm). Know if he's good? Sure looks like it on his site.

[N8YX]

Looks like I found one....W7AVK's kit (http://www.wb4hfn.com/Services/W7AVK/tr7ext2.htm). Know if he's good? Sure looks like it on his site.

I have a set of those. Good stuff...

[W1GUH]

I have a set of those. Good stuff...

Thanks. I emailed him asking if he had any left -- I'll order if he says yes.

[W1GUH]

He's got a few & one is on its way to me. This is going to be a fun project!

Thanks for the help.

[W1GUH]

It's on its way to me. Bob seems a very good guy!

[W1GUH]

Extender boars arrived to day. Look just like the pix on the web page.

[NQ6U]

Extender boars arrived to day. Look just like the pix on the web page.

Watch out fer them extender boars. They'll rip you a new asshole.

http://www.huntingsociety.org/boar2.jpg

[K7SGJ]

Only if you are the pig headed type.

[W1GUH]

Well, I CAN be....but try not. Yep, those came (thus resulting in even more of them) and so did the boards!

[n2ize]

Boards ?? What kind of radios have boards ? None of my radios have boards.

[W1GUH]

Boards ?? What kind of radios have boards ? None of my radios have boards.

I hear ya John....but there are BA's with boards. The R-100, ca 1959 had some very innovative PC boards -- including the bandswitch sections. Really made construction a lot easier -- didn't have to wire all the terminals individually.

And the TR-7 deserves a pass on this issue. Yep, all the works are on boards that plug into a mother board. But they're BA type boards with conventional components....and very easy to fix and work on, especially with OF eyes!

But your comment is well received!

[kb2vxa]

What kind of radios have boards you ask?