Mike, thank you so much for your time and expertise. The new video repair series will be a hit for sure. I can't be the only newbie out here, calmer ing for more. I for one want to say Thank you "Teacher". I will be on time to class. Joel
i've bought almost all my equipment just never used it yet, watching videos like this will make it to when i finally start doing my own repairs. just picked up an almost complete set of sam's..i got the bk precision dynascan cb service center and signal generator and freq counter. got a 100 mhz oscilloscope
This is great stuff Mike. Doing a series on troubleshooting cb radios will bring your already great channel to the top of UA-cam. Even I enjoyed watching this type of video. Keep them coming brother.
I commend you for your enthusiasm as well as for wanting to educate your application in a broad scope. I myself started out as an FCC license first class technician. But this is not about me it's about the subject matter in question. Please elaborate on certain loading and burdens that test equipment can provide or in this case abstract and subtract one's critical findings. You may want to let the observer know that he or she must be aware of the equipment that they're using, that it can absolutely cause a irregularity and what we would take for granted as a normal reading such as an old v o m Simpson is an example. "Ohms per volt". Keep up the good work and may the electron force be with you....!!!
Mike this repair and troubleshoot series will be come populair. Good solid information. Fast troubleshooting. Excellent. The advice to buy a simple broken radio got me started and it worked. so it will work for other people. About equipment, fancy stuff does not make a better service man. I love equipment but as you stated a voltmeter and a scoop tackled many problems. Down the road of experience i bought better equipment. Keep it coming Mike i look forwar to it.
Thanks Mike - this one was more help than either of us could have imagined! I was given a box of CB radios to play with - most of which were dead. One, in particular, is labelled Korinna KSB-18. I found one old source of schematics but they haven't replied. I have been a long time follower of yours and, tonight, this video popped up on my UA-cam feed - and I recognised the board! - OK mine is the 18 channel and this is the 40 - but I now have a digital copy of Sams manual that will assist in getting the thing to transmit again. Many, many thanks from Australia!
Always nice having a Schematic- especially a "service schematic" that shows test points and voltages etc. It is troubleshooting and repairing electronics WITHOUT any supporting documents that I'd like to see. That is were the real expertise is shown. Instruction and helpful cct troubleshooting shortcuts/hints/tips would be most appreciated for those situations.
Mike my name is Mike also. Oh my god you are wonderful. I have loved to work on CB almost for ever. I have always want to be taught how, but never found anyone who would. Now I have Thank you so much for spending you time to show us how its done. I will consider helping you out also. Everyone should also. Keep up the great work you are doing. I cherish these videos. Thanks again..................................................
I enjoyed this video very much. Thank you for mentioning voltage levels while you are testing. Nobody else seems to do that. Hopefully, one day I will understand the part about using an oscilloscope to test the transmit output without blowing the scope. I am hoping to use an old Tecktronics dual trace 100Mhz. I still would need a frequency generator and counter before I begin. Probably an attenuater or something for the pl-259 output too. I'm finding that it can be difficult to locate schematics for old radios for free or even data sheets for IC's. Buying a $15 to $30 manual is tough when the radio is valued at $20 (I'm just tinkering, not pro repair). I got what you said about downloading manuals for other radios with the same chassis. But, how do you identify similar chassis without having seen a bunch of radios's? Does the board have some sort of ID number on it? Also, how do you visually identify smt components and their values? Because of newer smt, I am glad you are using vintage radios in your vid's.
I found this video while trying to find out why a 10.240 crystal fried. I've never seen this happen before. something created a massive amount of heat to cook the legs right out of the board. ( cobra 21 ltd ) Such a clean looking older radio too. Anyway, I'm not a tech, not even close, but tinker on my own stuff. Enjoyed the plain language run down on how to find problems. Side note: I have a friend, who, if I didn't know was not a radio tech, I would swear that was him voicing this video. You two sound identical!
I have a Washington that was modded before me. Sometimes it wont be able to put out or receive and if i tap on the middle left top of the radio it works again. Something must be loose. Buying the service book . Thanks for the video.
Thanks Mike, you are a great teacher. Time to try and fix my Cobra 89 XLR, low transmit power (around 1 Watt). I have the schematics. Ooh boy, here we go.
Hi Mike! Your disrespect for the extra channels was hilarious. Ive got a Cobra 25 doing the same thing as your radio. The last time it worked I picked up the mic and pressed to talk and the needle hung in the middle. Sunday I took it to the CB shop and it worked fine. Come monday morning mounted in the truck it was dead. Theres no squelch noice but the needle moves when the mic is keyed up.
Iv played with electronics since I was 16, im now 40. I. Still scratch my head at times but a break here and there aways works. Always have a coffee on standby. Works every time :-)
Bravo.......I'm lucky if I have wire schematic .......old school.....90 % of time its the cord.....switches.....fuse......great to see though process.....cheers
As "they" say, there's nothing to it but to do it. As I say in the beginning of the video, you have to start somewhere. Start with the basic's and look at major circuit blocks. Don't so much concern yourself with every single component in every circuit. Look at what you should see from the "output" of each major circuit. The main thing to remember is there are hundreds, possibly thousands of components between the power (13.8VDC / system voltage) and ground. Start with major blocks of the circuit, that's were the block diagram comes in handy. If you don't see what is expected from each "block" output, you have found the 'block" where the fault is. Then it's just a matter of back tracing and diagnosing what is wrong with that portion/block of the circuit. Mike KC3OSD
I find those switches and also most ptt switches have little brass rails that the copper clips slide on. They are sometimes black or green with tarnish and only disassembling them and sanding the rails clean will work. Some are not easy to replace (unobtainium) and cleaning them is pretty easy.
Really interested in seeing these type of videos. Computers are my trade but CB/HAM has always been a major interest but never seemed to have the time or spare funds to get into servicing/repairing. I have a basic understanding and can follow most everything I watch but have often thought I would like to see this type of video with a little more tutelage in it. Nice one Mike and thanks
Thanks for sharing your knowledge with us, Mike. Can you go through bringing the radio back to factory with us? That would be pretty interesting. I Look forward to learning all I can from you.
Mike, great videos. I have a question about the oscilloscope. What is the range for working on electronics. I see them for sale with different ranges. I appreciate your advice. I saw some cheaper ones that seemed to be in the lower range ie... khz. Thanks
If you want 2% accuracy or better then you want to multiply the frequency you want to sample by 5. 5 times the frequency gets you 2% or better accuracy with imperceptible distortion of the waveform. In the real world 2 times the frequency is usually all you need if your working on radios. If you only work on HF radios (30 MHz and below) a 60 MHz scope is all you need. The advertised bandwidth of a oscilloscope is the "3dB point". If it's a 100 MHz scope the signal will be 3dB down or 1/2 the amplitude when viewing a 100 MHz signal.
@@larrygreen8520 I work on pretty high frequency amateur radio equipment. L, S, C and X microwave bands or up to about 10.2 Gigahertz. Plan on getting into the Ku and K bands next year. That's up to about 26.5 Gigahertz. There's a few K band AMSAT satellites I would like to work.
Well I would say you've mastered the field. I'm a 69 yo retired hvac service man and have enjoyed messing with the circuit boards. I have a lot to learn but not sure time left to absorb. Thanks for your videos.
G'Day from DownUnder, Mike, am really enthralled with Your videos. You're Certainly a Specialist!!!, would you have a similar video, Troubleshooting no receive or transmit in a ts820s?, as that I have one of these machines, I can find one relay but not the other . I keep having Mind Blocks and it's driving Me Crazier!!!, I'd appreciate Your input, Thanks
Hey Mike I really like your videos and how you do trouble-shooting. I have a question for you... I do not repair Radios but a friend of mine brought in a Cobra 21 into my shop for repair... the question is do you need to have the Antenna plug into the radio when you are trouble-shooting and does SAM's have a manual for that Radio
I use 3 HP GPS time and frequency reference receivers into Stanford Research Systems distribution amplifiers to feed the 10MHz clock reference input on all my test equipment. They are good for accuracy of 1 X 10 to the -14 after about a week of runtime. They provide several decimal places more accuracy than I could ever possibly need. For the amateur radios I use for satellite work I use a Stanford Research Systems rubidium time standard. Think that one has a accuracy of 1 X 10 to the -11. Plenty enough accuracy for working satellites on 23cm.
@@mikesradiorepair I used a RS components frequency standard for years before the gps it was housed in a quality metal case in a nice blue colour. Never seen another like it either quite rare. But it never let me down. The older stuff was built to last. And i liked it because it was roughly the same size as my Blackstar frequency counter which isn't that big
Good stuff i like all of your videos i have watched so far , need to know how to use some of the equiment & where to hook what to ? Thanks so much for what you do ! Richard.
Good advice, Mike. I've noticed you often refer to some radios as "my radio". I'm assuming that you don't keep them all. Is there really a market for used, working CB's? I do a little repair work, mostly for fun. But, being retired I'm not opposed to making a little money to support my habit.
You were saying that you cant mess it up more..well I dont know how many times I did just that, messed it up even more...to the point that it was not worth fixing..or I did not have the money to do it..so I dont know about saying that...it was a very good video, by the way..
Disassembling the radios without damaging them can be tricky sometimes. I fixed a Motorola cb-555 that required a lot of desoldering, labeling and flipping the thing over many times just to get thing free enough to begin working on it. It's time consuming if it's your first time dealing with some models.
20MHz is useable but limits actually viewing the waveform. If you plan on working on CB's 50MHz is more than enough. The highest frequencies you will normally run into are in the 34MHz range.
Hey Mike, I really like your trouble-shooting Skills and I am just wondering... when repairing a CB radio do you need to have the antenna plug in. I am a bit confuse about how this works. I would really like if you can explain this for me. Thanks for the great Video.
+AS28g To test transmit you should have a dummy load attached. It's best not to transmit on air when working on radios. And on receive you would have a signal generator or communications test set attached to supply the input signal.
Thanks Mike, great video. I'm right at this point in my hobby. Would you have the number for the Sam's manual for a Cobra 29LTD. I'm starting with a bunch of them and the Cobra 25. Keep them video's coming.
Very clever and may I ask I do have an Icom 760 and sometime the audio recieve is working normal and okey but there are times when the audio recieve will suddenly drop meaning the audio will become low even on 12 or 3 o'clock volune settings. What can be the problem? I know a ham fellows once said that it might be the relay LY2-0-DC12 parts and I'm looking to avail one just in case. As I was watching your video I was hoping I can get your professional advise about the sickness of my radio. Thank you and will hope for your reply. 73
Hi Mike, can you advise me please, just dug out an old 80ch AM FM SSB cb radio I was given a few years ago, the radio is a Major M588 on the PLL 02A chip, this radio had a bunch of badly done and messy mods which needed removed, I started this a couple of years ago and then we had to move house due to my partner needing to be close to her parents due to illnes, just dug it out again to complete the job, It now has TX but on a different frequency to the RX, RX sounds good (removed open clarifier and put it back to stock replacing the diode and resistor, removed voltage from clarifier) sorted FM Mod to a working version FM TX audio is now good, replaced all VRs on the boards as the tops were popping off, removed a strange 10KC shift mod without transistor and resistors also removed an add on crystal trimmer tagged onto the back of the high band crystal to get the old UK 27/81 channel shift. The problems I have left is that when on USB RX the needle is pegged hard to the end of the meter scale as soon as USB is selected, AM FM and LSB are fine on RX, any idea what to look for to cure this? TX is off frequency on all modes, step one PLL alignment tunes to 10.240 MHz exactly through the recomended 1,000 pF cap and when on step 2 of the alignment of the off-set frequency alignment the max readings I can get from TP4 are around 18.020.04 MHz instead of 20.555 MHz on High band and 17.795.19 MHz instead of 20.330 MHz on Mid Band which has stopped me in my tracks? I have a scope, analog and digital MM and a 7 digit frequency counter which reads true on my amateur radios, here is a link to the schem if needed www.cbtricks.com/radios/major/m588/index.htm Another thing to note is that the NB and ANL switches are now empty and they must have been bypassed when the rig was first modified (these switches were used for mods alone) there is also no PA (wires and rear skt removed) I dont care about these missing functions. Thank you
copykon When your paying a tech to do the work it can get to that point. If it's a family heirloom price may not be of concern. It does get to a point where some radios are in such rough condition that it is honestly cheaper to buy one in better condition then it is to restore a radio in horrible condition. The advantage if your fixing it for yourself is the only cost is parts. A lot of the shops out there today don't do repairs, they just tell you you need to buy a new one from them. Those are the shops to avoid.
Best way to start is buy some faulty radios so you own them, Then try fix them. Don't go straight into other peoples radios. Even if you understand the schematic because you need to also practise soldering and neatness. Nobody likes a bad repair. Or a ton of solder.
I have found the voltage regulator dying, I don't remember numbers etc, but it was just behind the crystal section on the right , in front of and to the left of the RF section, have found the zener diode let go More than once.
great video mike ! like you say, could fix that with just a meter, always check the basics first ! tbh i think i would just short the switch as who ever uses pa anyway ? lol :)
hey Mike. My Uniden Washington is original and mint, barely used. This radio (8719 pll) has stopped showing output whatsoever when hooked up to an swr meter. meter needle doesn't move. BUT on the RF meter on the radio it still swings and bounces up on am and ssb. However I notice it has more sensitive swing on USB than on LSB... Is the damn thing fried? It's almost as if it transmits but not at the power it should. And yeah, no needle movement on my inline swr/power meter...yet it seems to be putting out power?! Perfect coax connections too. I'm stumped. It does transmit as far as a couple streets over on my b100 antenna. I'm so frustrated. I can't figure it out. Are my finals fried? Is "half-fried" a thing? What gives?
For starters test into a dummy load not a antenna. You want to eliminate any possible outside faults. If you have low or no output power into a known good test system just trace the RF power amplifier circuit with a oscilloscope to see if and where your losing stage gain.
@@mikesradiorepair thank you for the advice. I opened up the pcb area underneath and turns out one of the coils' legs was unsoldered (broken joint) and I soldered it back on. Someone had spread the coils once upon a time and while I was pinching them back together the other day I must have accidentally pressed too hard and broke the joint underneath. Works perfect now. Love your videos by the way!
I hope you can answer this. I have a cobra 139 / 23 chan ssb. I have no power to the pa/cb switch. Where does it come from? I can't tell on the schematic.
hello friend I'm from Colombia I have a radio from the general electric is the 3-5804C turns on but does not give sound has a burned resistance, could I give me the schemes to see what value is that resistance and change it?
I was un-screwing the " finals" to put new heat sinking compound behind them because they were dry and one was getting very hot then the radio would not work right. I used a magnetic screw driver and now the radio sound like its off. Is it fixable and worth it. Its a General Lee
Terry Fennell Magnetic screwdriver shouldn't have done anything. What do you mean by "sounds like it's off"? Frequency off, audio distortion in receive or transmit.......
I can hear my friend talk but he sounds off Frequency and he can't hear me at all , and my meter show that I am putting out a signal. It would work untill it got hot and I did that to it
Family has been in the electronics repair business since the 1940's. Have a building full of service manuals for everything from TV's to record players to CB radios. And yes, there is pretty much a manual for every different radio.
What component is usually defective in a cobra 29 Ltd classic when the transmit LED goes out on key up mode ? I have done troubleshooting from one end to the other and cannot find out why I do not have transmit. I have voltage from the voltage regulator. I have oscillation on xtal 10.240. The keying transistor Q 21 seems ok after having tested it, yet I am losing voltage on r96, r94 and c 71 plus other areas in the vicinity. I have changed out numerous capacitors and checked others. C 112 and C 119 have also been replaced along with the audio chip. I have perfectly good receive as I can key up into the radio from a radio near by. Help please !
Can you tell me how to restore the transmit at this point in regard to the PLL ? I really don't need to restore this radio, but because of all the time I have put into it, this would be a learning curve for me and also preserve my sanity. Thanks
great vid. Can i send you a saturn galaxy base that has no trans or recev. it has worked in the past but just stoped., i dont think it has been monked with,. it does power up. id lv too see it back up and running again. 73
Mike I'm a technician and I love your video. Keep up the good work your doing helping ppl :)
You in uk
Mike, thank you so much for your time and expertise. The new video repair series will be a hit for sure. I can't be the only newbie out here, calmer ing for more. I for one want to say Thank you "Teacher". I will be on time to class. Joel
Happy to help.
i am no newbie and i am like you. i check for new videos every day. i wish i had a teacher like Mike 20yrs ago.
I wish I found Mike to do my radio work 20 years ago.... The money I could of saved and the "hacks" my radios wouldn't of suffered....
I am using Stryker SR-955 CB Radio since 4 years. No, such problem occurs till now. One of the best radios so far in have seen.
@@mikesradiorepair do you take in radios for repair got an old cobra 1000 that seems the box in an out of lock state
i've bought almost all my equipment just never used it yet, watching videos like this will make it to when i finally start doing my own repairs. just picked up an almost complete set of sam's..i got the bk precision dynascan cb service center and signal generator and freq counter. got a 100 mhz oscilloscope
This is great stuff Mike. Doing a series on troubleshooting cb radios will bring your already great channel to the top of UA-cam. Even I enjoyed watching this type of video. Keep them coming brother.
I commend you for your enthusiasm as well as for wanting to educate your application in a broad scope. I myself started out as an FCC license first class technician. But this is not about me it's about the subject matter in question. Please elaborate on certain loading and burdens that test equipment can provide or in this case abstract and subtract one's critical findings. You may want to let the observer know that he or she must be aware of the equipment that they're using, that it can absolutely cause a irregularity and what we would take for granted as a normal reading such as an old v o m Simpson is an example. "Ohms per volt". Keep up the good work and may the electron force be with you....!!!
Mike this repair and troubleshoot series will be come populair. Good solid information. Fast troubleshooting. Excellent. The advice to buy a simple broken radio got me started and it worked. so it will work for other people. About equipment, fancy stuff does not make a better service man. I love equipment but as you stated a voltmeter and a scoop tackled many problems. Down the road of experience i bought better equipment. Keep it coming Mike i look forwar to it.
Thanks Mike - this one was more help than either of us could have imagined! I was given a box of CB radios to play with - most of which were dead. One, in particular, is labelled Korinna KSB-18. I found one old source of schematics but they haven't replied. I have been a long time follower of yours and, tonight, this video popped up on my UA-cam feed - and I recognised the board! - OK mine is the 18 channel and this is the 40 - but I now have a digital copy of Sams manual that will assist in getting the thing to transmit again. Many, many thanks from Australia!
Always nice having a Schematic- especially a "service schematic" that shows test points and voltages etc. It is troubleshooting and repairing electronics WITHOUT any supporting documents that I'd like to see.
That is were the real expertise is shown. Instruction and helpful cct troubleshooting shortcuts/hints/tips would be most appreciated for those situations.
Mike, thanks for the pep talk. I like your common sense approach to trouble shooting. Just found your channel.
Hey all the way in Guyana here realy is motivated by your teaching you have truly done a whole love.Big up.
Great idea to let us join you, while you troubleshoot your your projects... You keep it simple, and not intimidating... TNX...
Mike my name is Mike also. Oh my god you are wonderful. I have loved to work on CB almost for ever. I have always want to be taught how, but never found anyone who would. Now I have Thank you so much for spending you time to show us how its done. I will consider helping you out also. Everyone should also. Keep up the great work you are doing. I cherish these videos. Thanks again..................................................
I enjoyed this video very much. Thank you for mentioning voltage levels while you are testing. Nobody else seems to do that. Hopefully, one day I will understand the part about using an oscilloscope to test the transmit output without blowing the scope. I am hoping to use an old Tecktronics dual trace 100Mhz. I still would need a frequency generator and counter before I begin. Probably an attenuater or something for the pl-259 output too.
I'm finding that it can be difficult to locate schematics for old radios for free or even data sheets for IC's. Buying a $15 to $30 manual is tough when the radio is valued at $20 (I'm just tinkering, not pro repair). I got what you said about downloading manuals for other radios with the same chassis. But, how do you identify similar chassis without having seen a bunch of radios's? Does the board have some sort of ID number on it? Also, how do you visually identify smt components and their values?
Because of newer smt, I am glad you are using vintage radios in your vid's.
I found this video while trying to find out why a 10.240 crystal fried. I've never seen this happen before. something created a massive amount of heat to cook the legs right out of the board. ( cobra 21 ltd ) Such a clean looking older radio too. Anyway, I'm not a tech, not even close, but tinker on my own stuff. Enjoyed the plain language run down on how to find problems. Side note: I have a friend, who, if I didn't know was not a radio tech, I would swear that was him voicing this video. You two sound identical!
Mike,
Look forward to those repair videos. Never know what new tidbit may be useful. And, you're never to old to learn something new. :-)
I have a Washington that was modded before me. Sometimes it wont be able to put out or receive and if i tap on the middle left top of the radio it works again. Something must be loose. Buying the service book . Thanks for the video.
Thanks Mike, you are a great teacher. Time to try and fix my Cobra 89 XLR, low transmit power (around 1 Watt). I have the schematics. Ooh boy, here we go.
Great repair video! Thanks for sharing! I'm also looking forward to some restoration videos.
Hi Mike! Your disrespect for the extra channels was hilarious.
Ive got a Cobra 25 doing the same thing as your radio. The last time it worked I picked up the mic and pressed to talk and the needle hung in the middle. Sunday I took it to the CB shop and it worked fine. Come monday morning mounted in the truck it was dead. Theres no squelch noice but the needle moves when the mic is keyed up.
Iv played with electronics since I was 16, im now 40. I. Still scratch my head at times but a break here and there aways works. Always have a coffee on standby. Works every time :-)
Mike thanks for the video it was very informative. I look forward to more how to's. Farrell
yeah.... i kinda started wiring mikerphones first then when up from there but still learning your right Mike don't give up sometimes hard to do!! 😩😁
mike this is great teaching and showing how to great job ,please do more great job
Bravo.......I'm lucky if I have wire schematic .......old school.....90 % of time its the cord.....switches.....fuse......great to see though process.....cheers
Thanks for the video im really looking forward to the repair videos.
A great instructional video. Never repaired a cb radio, but have a couple with the same problem illustrated.
As "they" say, there's nothing to it but to do it. As I say in the beginning of the video, you have to start somewhere. Start with the basic's and look at major circuit blocks. Don't so much concern yourself with every single component in every circuit. Look at what you should see from the "output" of each major circuit. The main thing to remember is there are hundreds, possibly thousands of components between the power (13.8VDC / system voltage) and ground. Start with major blocks of the circuit, that's were the block diagram comes in handy. If you don't see what is expected from each "block" output, you have found the 'block" where the fault is. Then it's just a matter of back tracing and diagnosing what is wrong with that portion/block of the circuit.
Mike KC3OSD
Hi Mike! Just wondering if you were planning on putting out anymore videos? I love your videos. We need more content. Please! Stephen KO4FYZ
You are a awesome tech. Thank you for producing these videos.
Thank you sir you helped me with my cobra 25 night watch. Thank you very much
I find those switches and also most ptt switches have little brass rails that the copper clips slide on.
They are sometimes black or green with tarnish and only disassembling them and sanding the rails clean will work.
Some are not easy to replace (unobtainium) and cleaning them is pretty easy.
❤
Really interested in seeing these type of videos. Computers are my trade but CB/HAM has always been a major interest but never seemed to have the time or spare funds to get into servicing/repairing. I have a basic understanding and can follow most everything I watch but have often thought I would like to see this type of video with a little more tutelage in it. Nice one Mike and thanks
thanks mike got an old 132 corba the receive cut's in and out great video
Again a really nice job Mike, that's the kind of stuff I like. Cheers
Thanks Mike . I enjoy your videos very much. I have a question on Tantalum Capacitors. Can you replace Tantalum capacitors with Electrolytic ones ?
Man thank you so much, just know that you are helping me a lot!! Your efforts are so greatly appreciated!
Thanks for sharing your knowledge with us, Mike. Can you go through bringing the radio back to factory with us? That would be pretty interesting. I Look forward to learning all I can from you.
Great video....but I don't have the patience!!!! Please keep doing repairs and keep my junk in good working order, thanks!!!
A great example off KISS, “ keep it simple stupid “!
Excellent! Looking forward to those videos. I have to start on my pile someday! Thank you.
Mike, great videos. I have a question about the oscilloscope. What is the range for working on electronics. I see them for sale with different ranges. I appreciate your advice. I saw some cheaper ones that seemed to be in the lower range ie... khz. Thanks
If you want 2% accuracy or better then you want to multiply the frequency you want to sample by 5. 5 times the frequency gets you 2% or better accuracy with imperceptible distortion of the waveform. In the real world 2 times the frequency is usually all you need if your working on radios. If you only work on HF radios (30 MHz and below) a 60 MHz scope is all you need. The advertised bandwidth of a oscilloscope is the "3dB point". If it's a 100 MHz scope the signal will be 3dB down or 1/2 the amplitude when viewing a 100 MHz signal.
I'm not sure I understand your 3db aspect.
OK I understand the-3db. What would be the max frequency you've worked with on these boards?
@@larrygreen8520 I work on pretty high frequency amateur radio equipment. L, S, C and X microwave bands or up to about 10.2 Gigahertz. Plan on getting into the Ku and K bands next year. That's up to about 26.5 Gigahertz. There's a few K band AMSAT satellites I would like to work.
Well I would say you've mastered the field.
I'm a 69 yo retired hvac service man and have enjoyed messing with the circuit boards. I have a lot to learn but not sure time left to absorb.
Thanks for your videos.
Mike, we did enjoy your work a lot. Is all well with you?
It sure is a victory to resurrect a CB radio from the grave, I've had more wins thans losses, and I'm a novice.
Get the books and study the rest will come naturally. Right Mike practice practice
awesome these videos are what I like to see to help me learn how to fix and tinker with cbs
G'Day from DownUnder, Mike, am really enthralled with Your videos. You're Certainly a Specialist!!!, would you have a similar video, Troubleshooting no receive or transmit in a ts820s?, as that I have one of these machines, I can find one relay but not the other . I keep having Mind Blocks and it's driving Me Crazier!!!, I'd appreciate Your input, Thanks
thank you enjoyed your video, very informative, well explained clear and to the point
Hey Mike I really like your videos and how you do trouble-shooting. I have a question for you... I do not repair Radios but a friend of mine brought in a Cobra 21 into my shop for repair... the question is do you need to have the Antenna plug into the radio when you are trouble-shooting and does SAM's have a manual for that Radio
Thou shalt check voltages! Pretty high on the debugging commandments.
good video, like the idea about ground for meter one less lead to get loose
Also a frequency standard reference oscillator to calibrate your counter etc helps. I use a GPS system.
I use 3 HP GPS time and frequency reference receivers into Stanford Research Systems distribution amplifiers to feed the 10MHz clock reference input on all my test equipment. They are good for accuracy of 1 X 10 to the -14 after about a week of runtime. They provide several decimal places more accuracy than I could ever possibly need. For the amateur radios I use for satellite work I use a Stanford Research Systems rubidium time standard. Think that one has a accuracy of 1 X 10 to the -11. Plenty enough accuracy for working satellites on 23cm.
@@mikesradiorepair I used a RS components frequency standard for years before the gps it was housed in a quality metal case in a nice blue colour. Never seen another like it either quite rare. But it never let me down. The older stuff was built to last. And i liked it because it was roughly the same size as my Blackstar frequency counter which isn't that big
Good stuff i like all of your videos i have watched so far , need to know how to use some of the equiment & where to hook what to ? Thanks so much for what you do ! Richard.
What mhz scope do you recommend. I'm looking at a 60 mhz. great video by the way!
Dude you just helped me fix my old Cobra 142
So awesome Mike!!! Great vid. Love the encouragement
Fantastic explanations
Mark, GOOD MORNING. I hope your redesigning of your work space is going GOOD. Been 4-6 week's since you were in destruction mode. Thankyou
Good advice, Mike. I've noticed you often refer to some radios as "my radio". I'm assuming that you don't keep them all. Is there really a market for used, working CB's? I do a little repair work, mostly for fun. But, being retired I'm not opposed to making a little money to support my habit.
You were saying that you cant mess it up more..well I dont know how many times I did just that, messed it up even more...to the point that it was not worth fixing..or I did not have the money to do it..so I dont know about saying that...it was a very good video, by the way..
Thanks for educational encouragement !
Omg I have the version B with the sliding mic amp bar, I love my xtra channels!
Thanks Mike, much appreciated
Disassembling the radios without damaging them can be tricky sometimes. I fixed a Motorola cb-555 that required a lot of desoldering, labeling and flipping the thing over many times just to get thing free enough to begin working on it. It's time consuming if it's your first time dealing with some models.
I did a video on a 555 and they are one of the trickier ones to work on.
nice videos mike can u do a video showing the various sections of the CB radios like the IF AF and RF ,,,sections ...thank you ...
Thank you for sharing
what mhz scope do you recommend? in looking at a 60 mhz older scope. and a new rigor 100 mhz. great video by the way!
20MHz is useable but limits actually viewing the waveform. If you plan on working on CB's 50MHz is more than enough. The highest frequencies you will normally run into are in the 34MHz range.
MikesRadioRepair great thanks
Mike's Radio Repair
Hey Mike, I really like your trouble-shooting Skills and I am just wondering... when repairing a CB radio do you need to have the antenna plug in. I am a bit confuse about how this works. I would really like if you can explain this for me. Thanks for the great Video.
+AS28g
To test transmit you should have a dummy load attached. It's best not to transmit on air when working on radios. And on receive you would have a signal generator or communications test set attached to supply the input signal.
Thanks Mike. I already has the signal Generator...just need a dummy load. Thanks again.
Thanks Mike, great video. I'm right at this point in my hobby. Would you have the number for the Sam's manual for a Cobra 29LTD. I'm starting with a bunch of them and the Cobra 25. Keep them video's coming.
Just look it up on cbtricks.com They have most factory manuals listed and also list sams manuals.
Very clever and may I ask I do have an Icom 760 and sometime the audio recieve is working normal and okey but there are times when the audio recieve will suddenly drop meaning the audio will become low even on 12 or 3 o'clock volune settings. What can be the problem? I know a ham fellows once said that it might be the relay LY2-0-DC12 parts and I'm looking to avail one just in case. As I was watching your video I was hoping I can get your professional advise about the sickness of my radio. Thank you and will hope for your reply. 73
Thanks Mike
Hi Mike, can you advise me please, just dug out an old 80ch AM FM SSB cb radio I was given a few years ago, the radio is a Major M588 on the PLL 02A chip, this radio had a bunch of badly done and messy mods which needed removed, I started this a couple of years ago and then we had to move house due to my partner needing to be close to her parents due to illnes, just dug it out again to complete the job, It now has TX but on a different frequency to the RX, RX sounds good (removed open clarifier and put it back to stock replacing the diode and resistor, removed voltage from clarifier) sorted FM Mod to a working version FM TX audio is now good, replaced all VRs on the boards as the tops were popping off, removed a strange 10KC shift mod without transistor and resistors also removed an add on crystal trimmer tagged onto the back of the high band crystal to get the old UK 27/81 channel shift.
The problems I have left is that when on USB RX the needle is pegged hard to the end of the meter scale as soon as USB is selected, AM FM and LSB are fine on RX, any idea what to look for to cure this? TX is off frequency on all modes, step one PLL alignment tunes to 10.240 MHz exactly through the recomended 1,000 pF cap and when on step 2 of the alignment of the off-set frequency alignment the max readings I can get from TP4 are around 18.020.04 MHz instead of 20.555 MHz on High band and 17.795.19 MHz instead of 20.330 MHz on Mid Band which has stopped me in my tracks? I have a scope, analog and digital MM and a 7 digit frequency counter which reads true on my amateur radios, here is a link to the schem if needed www.cbtricks.com/radios/major/m588/index.htm
Another thing to note is that the NB and ANL switches are now empty and they must have been bypassed when the rig was first modified (these switches were used for mods alone) there is also no PA (wires and rear skt removed) I dont care about these missing functions.
Thank you
What discourages me sometimes is when people tell me that things are not worth fixing.
copykon
When your paying a tech to do the work it can get to that point. If it's a family heirloom price may not be of concern. It does get to a point where some radios are in such rough condition that it is honestly cheaper to buy one in better condition then it is to restore a radio in horrible condition. The advantage if your fixing it for yourself is the only cost is parts. A lot of the shops out there today don't do repairs, they just tell you you need to buy a new one from them. Those are the shops to avoid.
Best way to start is buy some faulty radios so you own them, Then try fix them. Don't go straight into other peoples radios. Even if you understand the schematic because you need to also practise soldering and neatness. Nobody likes a bad repair. Or a ton of solder.
Mike, have you ever worked on an Olson Sidebander cb Radio? Mine has no receive. Can you point me in a direction where the issue can be?
Good video, will be of immense value to newbies .. like moi, thanks
The video poped up in my feed I was hoping it was a new one.
That would be a lot of help on the simple CB Radios . Thanks .
I have found the voltage regulator dying, I don't remember numbers etc, but it was just behind the crystal section on the right , in front of and to the left of the RF section, have found the zener diode let go
More than once.
great video mike ! like you say, could fix that with just a meter, always check the basics first ! tbh i think i would just short the switch as who ever uses pa anyway ? lol :)
I love these videos!
hey Mike. My Uniden Washington is original and mint, barely used. This radio (8719 pll) has stopped showing output whatsoever when hooked up to an swr meter. meter needle doesn't move. BUT on the RF meter on the radio it still swings and bounces up on am and ssb. However I notice it has more sensitive swing on USB than on LSB... Is the damn thing fried? It's almost as if it transmits but not at the power it should. And yeah, no needle movement on my inline swr/power meter...yet it seems to be putting out power?! Perfect coax connections too. I'm stumped. It does transmit as far as a couple streets over on my b100 antenna. I'm so frustrated. I can't figure it out. Are my finals fried? Is "half-fried" a thing? What gives?
For starters test into a dummy load not a antenna. You want to eliminate any possible outside faults. If you have low or no output power into a known good test system just trace the RF power amplifier circuit with a oscilloscope to see if and where your losing stage gain.
@@mikesradiorepair thank you for the advice. I opened up the pcb area underneath and turns out one of the coils' legs was unsoldered (broken joint) and I soldered it back on. Someone had spread the coils once upon a time and while I was pinching them back together the other day I must have accidentally pressed too hard and broke the joint underneath. Works perfect now. Love your videos by the way!
I hope you can answer this. I have a cobra 139 / 23 chan ssb.
I have no power to the pa/cb switch. Where does it come from?
I can't tell on the schematic.
YOUR SO GOOD IN ELECTRONICS KNOW HOW DID YOU GO TO TECH IN USA ??? THANKS
I need to start with buying some of your older test equipment you know what i need i dont , save me from buying what i think i need vs what i need .
One of my favorites to work on ...the g e
Fantastic tips!
Great videos Mike!!!!!
i have TM-261 KENWOOD.. the problem is the weak RX.. FINAL is Good how to troubleshoot this kind of problem ? pls
Thanks for the info on your vids.
hello friend I'm from Colombia I have a radio from the general electric is the 3-5804C turns on but does not give sound has a burned resistance, could I give me the schemes to see what value is that resistance and change it?
I was un-screwing the " finals" to put new heat sinking compound behind them because they were dry and one was getting very hot then the radio would not work right. I used a magnetic screw driver and now the radio sound like its off. Is it fixable and worth it. Its a General Lee
Terry Fennell
Magnetic screwdriver shouldn't have done anything. What do you mean by "sounds like it's off"? Frequency off, audio distortion in receive or transmit.......
I can hear my friend talk but he sounds off Frequency and he can't hear me at all , and my meter show that I am putting out a signal. It would work untill it got hot and I did that to it
could you please have some nice videos about 28 ltd classic, and maybe some just instructional audio from cb transmition
I'm curious of where do you get the manuals from and do you need one for every radio?
Family has been in the electronics repair business since the 1940's. Have a building full of service manuals for everything from TV's to record players to CB radios. And yes, there is pretty much a manual for every different radio.
How much is for the best cb radio you got there side band
How can I have 4 watts on channel 1 but only have 2 watt on channel 40 ? Any help would be appreciated or explanation cobra 25 ltd wx classic
Hi is the book available to find to trobleshut any radio
Hey Mike, how would I contact you regarding some pricing on restoration project?
How can I contact you for sending you 2 BC radios.
What component is usually defective in a cobra 29 Ltd classic when the transmit LED goes out on key up mode ? I have done troubleshooting from one end to the other and cannot find out why I do not have transmit. I have voltage from the voltage regulator. I have oscillation on xtal 10.240. The keying transistor Q 21 seems ok after having tested it, yet I am losing voltage on r96, r94 and c 71 plus other areas in the vicinity. I have changed out numerous capacitors and checked others. C 112 and C 119 have also been replaced along with the audio chip. I have perfectly good receive as I can key up into the radio from a radio near by. Help please !
+BJ S
It sounds like the PLL is out of lock and inhibiting transmit.
Can you tell me how to restore the transmit at this point in regard to the PLL ? I really don't need to restore this radio, but because of all the time I have put into it, this would be a learning curve for me and also preserve my sanity. Thanks
thanks for this video I needed to hear this.
great vid. Can i send you a saturn galaxy base that has no trans or recev. it has worked in the past but just stoped., i dont think it has been monked with,. it does power up. id lv too see it back up and running again. 73