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View Full Version : TR4/4A TR4A Just Curious



JDstr4a
08-12-2012, 10:14 AM
Rebuilding the original antenna which was snapped off. the cable was forced between the rubber gasket under the dash which didn't seem right. Looking through the exterior mounting hole noticed something through the hole I didn't recognize. Tried to find a reference with no luck. Sorry for the poor quality photos shooting through the antenna hole. What is it?
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0685.jpg
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0686.jpg
JD

sail
08-12-2012, 10:34 AM
Looks like might be part of the antenna bracket. Can't you get to it partially removing the passenger side footwell panel?

JDstr4a
08-12-2012, 12:30 PM
Exactly what it was. I didn't hear them fall when I disconnected everything and they way they fell seemed like they belonged there :wall: A magnetic pickup and hemostats got em out. Spent another 20 minutes looking for a nut I thought should be on there. The good news, I got it all back together and reconnected the drain tube for that area while under the dash. Now just need to figure out how to route the antenna wire.
Thanks again.
JD

KVH
08-12-2012, 01:58 PM
I'm curious what kind of radio you're to install. I've got an original TR radio, but I have to send it out for repair. New ones form Moss and others work better, sound better, offer more options, apparently fit OK and don't offend too many sensibilities.

JDstr4a
08-13-2012, 09:39 AM
Not sure if this radio is orginal or not (assuming it is) currently not connected to power. I just started on the antenna cause it was coiled up on the passenger floor and the mast was broken. Once I get the cable routed I'll hook up power and see what happens before I remount the speaker. Too many other things on my list to consider audio upgrade at this time.
JD
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0695.jpg
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0696.jpg

Mickey Richaud
08-13-2012, 09:53 AM
Hey, JD -

Looks like it may be original to your car (as a dealer item). Radios in the fifties and until '63 had a little triangle and "CD" at each end of the dial for the "Conelrad" emergency warning system.

Certainly appealing to keep your car period correct!

JDstr4a
08-13-2012, 10:12 AM
Thanks Mickey, ahh yes civil defense, get below your desk and cover your head against that nuclear explosion! Not sure what the BC/KC are, guess I'll have to Google!

Mickey Richaud
08-13-2012, 10:20 AM
Thanks Mickey, ahh yes civil defense, get below your desk and cover your head against that nuclear explosion! Not sure what the BC/KC are, guess I'll have to Google!


KC = kilocycles (now kiloherz)
BC, if memory serves, stood for "broadcast"...?

JDstr4a
08-13-2012, 04:45 PM
The rabbit hole is deeper than I thought. Since raining today, pulled the radio to get model number
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0699.jpg etc, and as soon as I tilted it rattle rattle. took off the inspection cover and viola spare parts!
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/DSCN0698.jpg
Maybe time for a blanking plate :smile:
JD

TR3driver
08-13-2012, 04:53 PM
If you feel like trying, any decent electronics shop (maybe even Radio Shack) should have a suitable substitute for that capacitor. However, polarity is important and you may have to do a little detective work to figure out which trace on the PC board is positive or negative. Chances are, though, that the negative lead went to ground and it will be easy to follow the trace around the board until you find a place where it connects to ground.

There is some chance I might have some information on it at home, I'll try to check tonight.

JDstr4a
08-13-2012, 05:38 PM
Thanks Randall. I've spent the last few hours scouring the internet for a diagram, with limited results. Old radios like this used to have diagrams on the inside, so tonite I need to clear the bench and make a clean work area to tear it down. As I recall the cases are like a puzzel to take apart,seems to be in solid condition other that the cap, looking at it closely it doesn't seem burnt anywhere so we shall see...
JD

mclaugh
08-13-2012, 08:19 PM
JD,

I'm sure you have discovered that you can buy a SAMS manual. It wouldn't surprise me if someone here has a collection of those and could send you a copy. But you probably don't need one real bad. A cap that big left a big space, and it shouldn't be hard to see where it came from once you get the entire board exposed, which you'll need to do anyways to solder a new one in.

-Why did it fall out? If from corrosion, you'll probably have to repair the circuit board also. It looks really clean inside though.

-Big electrolytic capacitors are usually used as power supply filters, or sometimes to couple the output of the amplifier to the speaker. Either way, the capacitance and voltage are not critical and can both be larger, the only problem is to find something that will physically fit.

-If you can't find one locally, try Mouser or Digikey online.

-Of course, there could be something else wrong once the cap is replaced, but it's the obvious place to start. Keep us posted.

BTW, thanks for the clear pictures.

-Tom

TR3driver
08-13-2012, 10:31 PM
The cap appears to be C1, the positive side should connect to the trace identified as test point 27.

https://i258.photobucket.com/albums/hh260/TR3driver/Radios/P29CHANNELMASTER6542boardlayout.jpg

https://i258.photobucket.com/albums/hh260/TR3driver/Radios/P29CHANNELMASTER6542boardlayout.jpg

mrv8q
08-14-2012, 01:02 AM
Applause from the gallery! Well done, Randall!

JDstr4a
08-14-2012, 06:27 AM
Found the space which was pretty easy as Tom suggested
https://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/cap3.jpghttps://i1140.photobucket.com/albums/n565/jdstr4airs/atenna/Cap.jpg

Confirmed by Randall's pictures, component side picture even shows stripe for polarity! Just need to find a replacement and my solder sucker. Thanks Gentlemen!
JD

JDstr4a
09-02-2012, 11:48 AM
Dang it! relaced capacitor, got light when connected to power, resoldered speaker wires, remounted speaker, put in radio and nothing! Speaker impendence ok and noise when checking, miliamps out of radio, but not even static. guess I'll move on for now and start checking for a period correct radio to swap out. :cry: