Build a AF & RF Signal Tracer

[TundraWalk3r]

Hi Rick,

Great video, very helpful. I really like that radio, too. Zenith is one of my favorites.

Matt

[AllAmericanFiveRadio]

@TundraWalk3r

Thanks Matt,

If I made this today I would not drill holes in the cabinet. I would put everything into another box. There are a lot of these still out there, but don't drill holes in it.

This is a very useful circuit and you can also detect FM signals.

Rick

[MickLBrad]

Hi Rick. Sounds like the Zenith is about due for a recap operation. You videos are a real bennifit to the younger folks (and some of us older folks too!) Back in the 60's I built a 3 transistor intercom and never used it much until I modified it for signal tracing. Worked great! Today, I have a couple of radios in the house and one in the car that have an auxiliary input for MP3 players and I think I'll go ahead and make a plug-in module for signal tracing. 73 de Mick - WB4LSS

[AllAmericanFiveRadio]

Thanks MickLBrad

Sound like it is going to be a useful Mod. I hope some of the younger folks are helped by the videos, and get interested in electronics.

[762girl]

WONDERFUL! Freaking brilliant. I love this stuff!

[AllAmericanFiveRadio]

Thanks 762girl

[oasfoose1]

Pink Floyd ;)

[trh847]

Hello Richard,

I did not get a clear understanding of the wiring changes you made in this mod. Could you expand the schematic to include the switch wiring and show where the red wire you attached to the green wire is attached in the circuit. I'd like to try this mod but I don't think I have enough information. Thanks!

[AllAmericanFiveRadio]

@trh847

If I was going to build this today I would put all the wires in another box, rather than drill holes in the radio cabinet. I did a video on the transistor signal tracer and it has a diagram of this circuit. It is the same circuit. I'll send it to you YouTube email.

[dream501]

Hello, will a 1N914/4148 diode work in place of the 1N34A diode?

Thankyou for your time.

Dan

[AllAmericanFiveRadio]

@dream501

It should work. If not Antique Electronic Supply has both diodes. And you do not have to drill holes in the cabinet, you put all that stuff in a small box and set it on top.

[toltec13]

Question: One end of the ground wire goes to the radio chasis, but does the other end go to? I'm puzzled.

[oasfoose1]

pink floyd! :D

[ZmajSnoshaj]

What is it with Pink Floyd and Zenith ;)

[BadChizzle]

I like the way you pronounce things, it adds to the fun for me. If you went through every word in anyones vocabulary, you would find such variations from the norm here and there. I suspect even in the guy just before me in these comments.

Rock on Rick!

[pbpix]

I think chassis is pronounced chas-ee

[decoflair]

Where did we hook up the black cable?

Was the Crosley radio actually turned on during the test period?

How do we know exactly where to place the red probe?

Thanks,

[AllAmericanFiveRadio]

The black cable is connected to ground of the test radio.

Yes.

By reading the wiring diagram you can determent where the RF is/should be, and where AF is/should be.

[decoflair]

AllAmericanFive:

Thank you for your response and dedication to this hobby.

Greg

[rowell5371]

ihave a radio that doesnt match the frequeny anymore to its display i suspect the rf amplifier am i right

[AllAmericanFiveRadio]

That sounds true. Most of the time if the stations are off the radio needs to be aligned. If it is an older radio you maybe able to find the information at nostalgiaairDOTorg

[wa4aos]

Hi, Have you had experience with doing a staggered IF alignment on a 455 KHz IF using an O Scope and sweep gen? This seems to be a lost art.

Thanks,

GLenn

[AllAmericanFiveRadio]

Sure. I have been using O Scopes and signal generator since high school. I have built three O Scopes, and no telling how many other kits and home brew stuff. I have written two book on antique radio repair.

[lovesavacuum]

Have watched several of your videos. They are very useful. I happen to be in the process of restoring a Sparton 746-PA console radio at the moment.

I would love to see a similar video about tube based FM stereo demultiplexer circuits and how they work.

[AllAmericanFiveRadio]

Thanks, and good luck with the Sparton 746-PA. Nice radio.

I have put the FM stereo demultiplexer circuits in the YouTube video to do list file.

[desertbard]

I use an old amplified computer speaker with much the same circuit. It is an extremely useful circuit.

Thanks for sharing it...

[AllAmericanFiveRadio]

That's great! Yes they are extremely useful in finding where the signal starts/stops and in finding noise. Thanks.

[ddl312]

sounds very nice.good tracer to i could try that!!

[AllAmericanFiveRadio]

I think you will find it to be a very useful troubleshooting tool.

And there's more information on the way.

[tnvol11]

Your videos and information are the most diverse and informative that can be found anywhere on the net.

Thanks,

tnvol11

[AllAmericanFiveRadio]

Thanks, I very much appreciate that. I'm studying the diagram for this unit to make it more useful as test gear, with as few changes as possible, but not making the changes unique to this radio.

Rick

[joernone]

Rick,

This is pretty slick. Came along a little too late though. Had to finally break down and buy a Heathkit tracer. But I'm looking forward to seeing what else you have up your sleeve for this puppy.

Regards,

John

[AllAmericanFiveRadio]

Hey John,

I'm studying the wiring diagram now and my goal is to make more useful test equipment from different parts of this AM&FM radio. Rick

[Ronbob59]

Nice job, Rick. Something else I need to build now..:>)

So, what's next???

Ron

[AllAmericanFiveRadio]

Hey Ron

I'm planning on adding to its capabilities. I have a few ideas that should make this radio into a very useful piece of test equipment with multiple functions. Rick

[damusician]

dude, what are you doing? you decreasing the value of that radio by modding it, lol! anyway, i thought about doing something like that with my 1948 rca victor am/fm radio to test the penncrest cassette deck, but i did hack into the right channel with a jumper and connected it to the left channel and the noise came out the left channel too so it must be the 2sb46 transistor.

[AllAmericanFiveRadio]

Yes I know and I was wondering how long it would take for someone to point that out. In this case it was one. I have three or more of them in the garage. This radio will be very valuable in 2883, lol!. Great about using the left channel for troubleshooting!!!! GREAT!

[AllAmericanFiveRadio]

When you need a signal tracer you really need one. A friend that works on radios brought one over that was giving him a fit. Everything checked out, all the coils, all the voltages, all the tubes are good and any other test I could think of. I used a tracer to find where the signal stopped. It was at the second I.F. can. We opened up the can and it was full of dust and dirt which shorted out the RF signal. After cleaning the insides of each I.F. the radio performed like new.