Basic troubleshooting and signal tracing procedures to repair a no modulation condition.

To help support this channel donations can be made at. www.patreon.com/MikesRadioRepair

[@Chuck-U-Farlie]

wow an actual signal tracing video! thanks for posting this. this is what separates the men from the boys in CB repair. folks if you see people tracing a signal through a radio before they start replacing parts, you've got a real repair tech.

[@rubengonzales7739]

God is good all the time. Enjoyed the very informative video sir thank you soo much 541 Tx.

[@eduardopower5254]

Amen

[@jeffpatton2633]

Love your videos Mike keep them coming!

[@stevenyamada70]

This type of walkthrough video is my favorite kind of troubleshooting video by far! Thankyou Mike. You're the BEST!

[@RC-Heli835]

22:35 There is not nearly enough of this type of information available on youtube for those who wish to fix things themselves. The tone generator tracing audio all the way to the drop out was the most amazing thing I've seen in a while.😀

[@CrucesNomad1]

Amazes me you know what things are and what to look for. As a driver I just did what the cb guy said to do. Never had issues with my radios.

[@mikeyf103]

Mike passed away from covid complications 😢Few years back

[@45AMT]

My Heathkit signal tracer is one of my most used Test equipment in my shop. Thanks for posting.

[@AndyDaviesByTheSea]

Hi Mike nice fault to show. I love the old test equipment and signal tracers are right up there. All the best . . . Andy

[@harbselectronicslab3551]

Just a trick for you Mike.........if you mount the camera off to the side and just use a mirror on the stand to look at the board you will have more room......this also has the benefit of allowing you to zoom in much closer and stay in focus because the lens to subject distance is more in the sweet spot of the focal distance.......once you do that, the image can be flipped back into the right orientation in the editing software......works a treat to get the camera out of the way, and allows the use of much bigger and better camera's........cheers John

[@jimkodysz5404]

Hi Mike Those are some good tips! I would like to thank you for putting up with the "inconveniences" to make these videos!

[@JAWS1376]

I enjoy all of your videos but this one is my favorites. I have about 20 radios in my collection and I've always wanted to do an alignment. Over the years I've purchase test equipment, only lacking a rf signal generator. I think I have everything else I need. Thanks for actually showing the testing instead of pausing the video. Could you ever show a full alignment of a cb/10m radio ?

[@roberttinsley551]

Mike you are (amazing).Lol, and today is March don't remember the day but the year is 2021 Mike you are amazing I love the way you did with this video I learned a lot and I am one that do make mistakes too and I'm going to do my best to keep from doing that thanks for your help

[@sovereignsavages5084]

My god what a beautiful bench!! Wow!!

[@TheDefpom]

You sound thrilled to have that on the bench.

[@RC-Heli835]

This is the best CB repair video I've seen yet. I like to see videos with problems that I would have never figured out and this is one of them. I want to see diagnosing, signal tracing and soldering. Hey Mike did you find a way to hook his light bulb up without it messing things up or just scrap the light bulb all thogether.

[@adrianclark9581]

An absolute fantastic lesson perfectly explained.👍

[@darynsax]

I really enjoyed this, found it very interesting. Liked and subscribed

[@sovereignsavages5084]

Common sense is not so common now days! Aloha mike for your time!

[@rockyfrance]

This is type of video I've been searching for! Thank you!

[@stevehappe8583]

Nice tutorial. Thank you. Don't have a signal tracer. Really don't know how to use one. I would like to learn how to use this along with a scope and function generator though. What is your background in radio? I heard you mention the fact that your grandfather had a repair shop. Wow! That would have been a great beginning. I am guessing you started out learning how to repair tube rigs. I have an old (1942) tabletop radio that stopped working. I replaced the power chord and the panel lights blew when I turned it back on. When it did work, it had great sound. And the fine woodwork is in pristine condition. Wish you were close by. I'd send it to you for repair.

[@opus1952]

That was a great video Mike, I learnt such a lot from you in this.Thanks.

[@cypherf0x]

You can use the diode mode on the multimeter to give transistors a quick check. It will look like diodes measuring from the base to the collector and emitter for NPN and the opposite for PNP.

[@robertschlotterbeck4314]

I built my own audio tracer with a few audio amps I got from a company in New York. ADAfruit sells all kinds of "breakout boards" that are useful. I even used one to build an amp for my base station mic. Great video. Not sure why but I always work backwards when trouble shooting, I don't know why but it always seems to work best for me, but then again, I don't work on other people's equipment, only my own.

[@lwoodt1]

Great vidoe Mike,,,how about a video tour of the tools and equipment that you use in fixing radios .

[@TheDefpom]

I have an old HeathKit signal tracer, comes in handy, and yes, a required tool at times when nothing else will work as well.

[@mikesradiorepair]

+TheDefpom A surprising amount of diagnostics can be done with nothing but a volt meter and a signal tracer. Back in the day every radio and TV repair shop had at least one if not several of them on the bench.

[@stuartprice6408]

Not wishing to teach granny to suck eggs, I found the vid very intuitive & I use my mobile phone's camera & it seems to work for me take a steady shot of a component or area I need to see for a quick reference & add a better light source a simple torch can help, then hold real steady in focus take a shot, seems to work for me without a Microscope its fast simple & 16megapixelles when you blow it up is great at seeing problems or small part no's or writing I well enjoyed the vid great stuff, & is nice to see someone at work that really know what they are doing

[@falcorthewonderdog2758]

Black box radio = job security for you You seem to handle repairing them pretty well.

[@902Steeler]

Thank you so much for sharing the knowledge Mike. So basically any semi conductor can be checked this way on both side. What about using a basic multi meter on ohms? Would that do the same thing? I just looked up how to home brew a signal tracer its really easy And I can use a guitar amp as my speaker. Can you test rf circuits with thr tracer as well?

[@martyaussie4538]

Geez Mike, you're stomping around in my territory now ;-) When you realised what the problem was, i was honestly waiting for you to say "the mode switch was still in CW mode", but you found that damn LED wire instead... I only say this, because i serviced a customers radio some years ago for many many many hours trying to find the open (or muted) audio problem, only to discover the mode switch was in CW mode right from the start. Stupid ME for not checking all the front panel controls BEFORE jumping inside with test probes. (and stupid customer for not knowing either lol) I hope this helps anyone out there to make sure they check the front panel FIRST. Doh !!!!

[@TRXLab]

oh what a nightmare the golden screwdriver is anywhere..thanks for sharing Mike!

[@roberttinsley551]

Wow Mike thank you so much for a better understanding of what I have been trying to do this video right here did give me such a better understanding if there is any way you can contact me . I don't know when you're going to be doing classes again if you're going to be doing classes again but I would like to try please let me know.

[@kennynvake4hve584]

I just got this week a Heathkit T-3 signal tracer...and going thru it, replacing the caps...IF YOU connect anything to while in the NOISE position ...it is 160 volts on that probe then..

[@cmj20002]

I love these radios. They are getting expensive to buy on Ebay. The Galaxy 95T2 is similar and also one of my favorites. This one and the 148F are the only Cobra radios that I would consider buying.

[@rpcomms1]

Ah that magic word "Common Sense",seems to lack these days Mike or not taught anymore lol Great vid and helpful for new techs. Rob 73's

[@GeorgeWMays]

Boy that was fun to watch. Are there signal tracers that should be avoided for any reason? Flakey brands? Impossible to get parts? Things like that....

[@jamesventura5106]

I asked YOU how to get Schematics on Radios and other items, but this time I like to ask if in all YOUR Stash of Books and other info if YOU might have a Schematic on a TX 800 Amplifier and if so, is it possible to purchase a Copy of as of it YOU have on it???? I just purchased one on eBay and its a complete Mess but to ME it is going to be a Project to work on, Thank YOU

[@mikesradiorepair]

What is it, a stereo, microwave RF, plasma amplifier. TX800 has been used for numerous amplifier makes.

[@robertbidot3238]

Would you be willing to do another one with the same issue. Also at least one bad pot.

[@tonyperry6702]

Nice vid. Learned a lot.

[@Justplast]

very good mick a1

[@backslider893inthebeerjoin7]

Cobra 200 GTL is one of the sexiest lookin radios😄

[@genwatie2191]

Id like to know where to get the schematic for old radios I got some rare radios but cant fix them

[@Travis141123]

How's that electronic course coming? Carlson is the only one doing anything worth paying for.

[@izzzzzz6]

What's the maximum voltage you can probe with the signal tracer? I was thinking to build a Mr Carlsons superprobe. Looks like a half decent cb radio.

[@mikesradiorepair]

Without looking at the manual I'm not sure. Never run into anything tube type I couldn't probe with it. Probe B+ rails all the time in tube type gear to check for AC hum. They were made in the day of vacuum tube equipment to work on vacuum tube equipment.

[@cw5059]

Mike, the dual op-amp you mentioned, is it the 4558 that is used in the President Lincoln + II ?

[@robertbidot3238]

On the cobra 200gtl, rv14 looks warped. I think that's the problem, but I can't find a part #. Could you please tell me what it is,or how to find it. Smd parts are hard to find if you don't know where to look for it. Or I can send it to you to fix it. Plus you would be laughing so hard after looking at the inside of the radio. Too many screwdrivers in the radio. Smd's scare me. Little to no experience with them.

[@PapasDino]

Whoever did the LED mod had to go WAY out of his way to select that as supply point! Sheesh!

[@rscelectrical7091]

Nice job buddy, I totally detest working on those radio's. Especially when it's been "Looked at", We all know those words spell trouble. Seems to be the "looked at" radio's are the only ones I see nowadays. Your lucky in the US, seems like you can still get reasonably decent service documents. Here in the UK we're lucky if we can get a half assed schematic.

[@bobsbarnworkshop]

guessing you could build a hi Z op amp audio tracer for CB voltages pretty easy...

[@kennynvake4hve584]

I really really need a probe...I made one using a oscilloscope probe that seems to work, but would like the original one..or one that works like the original...

[@Kennynva]

Do you think they wanted to see the modulation go up and down with the brightness of the LED???

[@jeffpatton2633]

I have a president Washington with no receive or transmit thing I’ll try signal tracer on receiver wish me luck!

[@Charlee2015]

Great video mike!!! Would the signal tracer work the same on the receive side of the radio? Chuck

[@mikesradiorepair]

Yes. Here's a video where I traced a static crash noise in the receiver circuit. kzbin.info/www/bejne/nnK3q2mMoN13h9U

[@Charlee2015]

@@mikesradiorepair thanks for getting back to me so quickly. Hanks for the link!!!

[@kevinrea7820]

Hi Mike, Could you let me know what the make and model of that probe is? I'd like to get one.

[@mikesradiorepair]

The one in the video is a Paco Z-80 signal tracer. Several companies made signal tracers back in the tube type era. Heathkit was probably one of the most popular.

[@kevinrea7820]

thank you Mike.

[@aoikweinstein5023]

Hey Mike, can I ask you for a favor? I've started at a CB shop and it is woefully inadequate in the schematic and service manual arena. Can I ask for some of your reference materials? I'll pay for whatever

[@DollarbillDollarbill]

You might try checking the transistor in diode mode. You maybe doing that already.

[@shotgunjim1itemsofinterest868]

Do you still work radios, if so how do I contact you

[@chrisguess1125]

Mike I really enjoy your videos... I have a question for you please sir. Do you use a iron on those SMT parts or a rework station (hot air)?

[@mikesradiorepair]

Chris Guess I use both and also hot tweezers and a Pace Thermopik. Which tool I use to remove components depends on the type and location. For everything but BGA installations I use a soldering iron for installation.

[@chrisguess1125]

Mike thank you for answering the question. I have never used the hot tweezers yet but I like the looks of them. I hated SMT when it first came out but it was mainly due to not liking change. After I got over that and started learning how to work with it I starting getting over the hate. I am getting older and I do find that just seeing the parts is only getting harder and harder lol

[@mikesradiorepair]

Chris Guess That's why I use a microscope. :-)

[@williamcolvin3609]

How is it possible to get the same power out of a microscopic circuit as a larger through hole circuit,just does not seem possible. You cannot run an air condition off an 18 gauge extension cord - according to wire size you just cannot get the power out of the micro wires in the components. Also do you show how your signal is input into the circuit,the Heathkit signal generator I have shows a 600 Ohm output and the radio is 50 Ohm antenna input. I have not checked it out to see if it work just got it and trying to figure out what I need to input the frequency for the channel 27.205 - a 1k tone - modulation?

[@mikesradiorepair]

+William Colvin In one word, technology. The first computer was the size of my house. My cell phone probably has hundreds of times more processing power than it did. Parts are smaller, more efficient and with computer aided design much more compact.

[@jamesventura5106]

Like to know where I can down a good Copy of a Schematic online for any Radio or any other Electronic Item that I may need???? What I have found are Schematics that are Poorly done and when I view them they are almost impossible to read????? I have been a Radio Enthusiast since I was in the Marines since 1776 but not until 1993 did I begin to really get into the Hobby, and now that I am Retired I like to learn as much as I can.... I have much of the Test Equipment needed and as I watch YOUR Videos I learn more and more what I need, can YOU help ME??????

[@mikesradiorepair]

There is no single source and many times there is none to be had. I have 10's of thousands of service manuals and that barely scratch's the surface of what there is. I have a complete set of SAMS Photofact filing cabinets (a few tons right there) that covers everything from TV's to tape recorders, radios, record players, etc. A complete set of Ryders service manuals and about 50 filing cabinet drawers full of factory literature. I have 10's of thousands of dollars invested in my service manuals and spend a on average a few hundred a month buying ones I don't have. eBay, the internet and public auctions are your friend is about all I can say. :-)

[@williamcolvin3609]

Make an Audio Test Probe.wmv Billm Audio Published on Jul 21, 2012 uses a 400 volt capacitor connected to a Radio Shack mini amplifier for a test probe.

[@paultomlinson528]

So annoying the red wire was almost next to the 12v on/off knob but it was run to the pcb else where..... those leds take about 60mA

[@gmcjetpilot]

What is a "Black Box Radio"....

[@philp.3978]

High output 10 meter mobile radios that can be converted to 11 meter CB.

[@gmcjetpilot]

@@philp.3978 OK illiagal, got it. Enjoy reading FCC violations list. Dumb.

[@jonmullins8460]

"Last week I couldn't spell radio teknishun, now I are one" .... The LED installer ....

[@Stover159]

You should show people the proper way to install a led with a dropping resistor be sure that’s a common modification and it probably don’t get dont correctly 90 % of the time

[@miraculousadrinetteithink309]

why dose when i go to youtube it dose this

[@richardwatson8822]

I can see why you don't like working on those radios .

[@ferrariguy6389]

Wow, you made it for 5 seconds before the giggle. Stop it!

[@robertbidot3238]

I always say you can't fix stupid, ( bad screwdriver tech).

[@miraculousadrinetteithink309]

what ima kid i dislike these my dad liks em' tho