#33 Tutorial: The bascis of troubleshooting for HAM / CB radio. Repair President Lincoln
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- เผยแพร่เมื่อ 10 ก.พ. 2025
- We explain on a President Lincoln 10m radio the basics of troubleshooting. This video is a bit longer because we really went step by step.
Hands down the best troubleshooting tutorial ever !
No nonsense, no gimmicks !
Dying Art of diagnosing to the component level !
Thank you for your work and thorough explanation !
Tip Top !
IMHO !
👍😉
Thank you!
This is truly a fascinating side of electronics , and reading the schematic road map, once you got to the 100 ohm resistor, capacitors jumped out at me, I'm sure a lot learned from this video, I'veI done this a 1000, times over 45 years, but still love to watch you working.
I fixed many hr2510 and lincolns over the years and found that Q125, Q127 and Q136 are the most common fault causing this sympthom. I have never seen the OP Amp failing when the tx/rx switching problem is present. Shorted caps droping the 8v line supply are common like C110 and the bad caps found in your video. Is very easy to find the faulty part begining from J302 8V (TX contol from CPU/PLL board) and follow it until the 8V drop. Good video and great troubleshoot process.
Again, amazing step by step troubleshooting with excellent commentary.It brings me back to my college years when we first learned to use test equipment. I have to say I watched almost with the same intensity as watching a suspense movie on tv.. trying to guess ahead of you as to what to look for, and what you'd see for measurements. Amazing use of block, schematic and component drawings.. I'd love to spend a year along your side to even learn a fraction of your expertise.
+Michelle Pucca Hi Michelle, thanks for the nice feed back and the kind words! I'm really glad that you like my videos!! All the best 73
A superb educational presentation that I see everyone here likes and appreciates. I myself gained a lot of insight into the trouble-shooting process. We are just fortunate to have someone like this fellow to guide and inspire us in the electronics art. I surely hope we see more of these as I look forward to these videos by this guy. A big thumbs up to this one!!!!!
Satellite_Guy Thanks for your awesome statement on my videos. That keeps me going!
I've watched a lot of troubleshooting videos over the past weeks, this is by far the best. Thank you so much for taking the time and effort to film this, I know it wasn't easy. Thank you, thank you, thank you.
Thank you!
Thank you for this video. My elderly uncle passed one of these radios to me with similar problems. I've enjoyed getting it working again with the help of this video!
+ledbthand Ah very good to hear!! Thanks for feed-back! 73
Awesome video. I have forgotten the basics of trouble shooting as I have been out of radio servicing for 17 years. Thanks for the refresher course.
+greasydot Thanks for nice feed-back. 73
A wonderful tutorial that teaches us the proper basics while understanding what we are doing! Please keep up the good work.
Thank you
Let me say thanks for making these videos.
You make it clear what is going on and how to take the needed steps to find the problem.
GREAT video.
Grant Fullen Hi Grant, always great to hear that you like the video! Thanks.
This is an amazing video, thanks so much for posting such videos. Thanks to Internet and youtube and knowledgeable and kind people like you, these kinds of tacit knowledge can be transmitted to people around the world. 73
Thank you!
Your pace was just right for this job. I understood everything perfectly.
I enjoy the way you take your time and explain everything in detail. Thank you, I am learning so much from you. You are a very skilled electronic technician.
Thanks for feed back 73
One of the best I've seen. Thanks for the detail, too many others I see don't show the details and details are exactly what we need to see. Thanks so much.
This is the best tutorial I have seen for radios. You have done a excellent job..
Thanks for the kind words! 73
My retirement hobby is the repair of early vacuum tube radios. I am now interested in learning to repair more modern solid state radio equipment, so I study and enjoy learning from you and wish to thank you for your excellent video. Some of the equipment that I work on is 60+ years old, the modern components have changed but what is still true is the measurements and rational reasoning involved in the repair procedure to both old and modern radio.
Thank you for your excellent work, you are a very good teacher.
Malcolm
KB1QCJ
+Malcolm Shaw Hi Malcolm, thanks for the kind words! Enjoy the hobby! best 73 Peter
Bravo! I've always wanted someone to show me the step by step troubleshooting process! Many thanks!
Glad that you liked it 73
I will thank Mr. Carlson for recommending you! Well done!
I found TRX bench via Mr Carlson too, thank goodness I did
Very good work. You got me with this one Peter, I was thinking the voltage regulator, and not a short. So I found a new technique by working towards the regulator. I hope you are well my friend and hope to see you back one day. 73 from Arizona USA.
A very good explanation step by step to find what was broken in this TX.Bravo for this do it your self demonstration !
glad that you likes it
Super video. Very clear and methodical. A teaching moment for me. I am new to the hobby and frustrated at my ignorance. You helped me in developing a plan when approaching repairs.
PaFrenchy Thanks for the nice feed-back! Keep on goining with your efforts 73
Very interesting and your level of detail is appropriate for a beginner. Thank you.
Hi Cliff, thanks for the feed back, glad that you like my videos.. All the best and Cheers.
Troubleshooting for dummies; excellent. Very much appreciate your thorough step by step process and thought process. I have watched your 4 part balun series which too is excellent, especially part 3 where you explain the basics of the math behind 4:1 and its clear how it relates to the winding.
Cant possibly thank you enough for taking all this time to educate us,thanks again.
Chrysiotis Thank you very much for your feed back!
Thank you for taking the time to do this. This is the first video of yours that I have watched and I will now start watching them all!
Thank you, glad to hear that.
Nice video Peter. I liked how you did the detective work to find the fault. Keep em comin.
Glad that you like it 73
Dear Respected Sir ,
You are great and you are very talented in explaining .
Thank you 73
Mein Präsident wurde wiederbelebt..Brilliante Fehleranalyse von bestechender Logik und ohne hochnäsiges Geschwafel .Einfach Klasse,Danke dafür.👍
LOL " Mein Präsident ist wiederbelebt"...Freut mich dass es dir gefallen hat. Danke für's feed back
I like watching your videos and Mr Carlson both of you are smart with repairing electronics
Amazing video very informative your ability to explain and describe can make even a novice understand. Keep up the good work look forward to seeing all your videos and learning in the process
john lira Hi John, thanks for your feed back! 73's
I like this video, because you explain that all the way to do plain to do repair one transceiver. It´s a good idea.
Glad that you like it. Thanks for watching 73
You are such a great teacher I wish you lived in my country
Every minuet of this video is golden. Brings back memories of the time when I bought my 2830. All those years ago. When I still had hair!! Klasse. Dankeschon Peter.
Thank you
You are a good teacher. Learning a lot from your videos. Thank You.
Thanks, glad that you liked it!
Awesome troubleshooting tutorial! Very well described all the way through. I’ve been fixing consumer electronics for about 25 years, but not so much transceivers. I was following with you with baited breath, couldn’t wait to touch the probes myself, lol. Very good explanation of how to breakdown the components through data sheet research to get a detailed understanding of function, as well as pinout of leads. Your description as how to locate components was also well explained, as well as how transistors of type npn and pnp are turned on by a high or low bias at their respective base leads. I was expecting the 100 ohm resistor to be open, or the IC supply pin to be shorted internally and pulling the 8v down. In which isolating its supply pin by unsoldering would lift the short (loading) and bring back the 8v showing the problem to be the IC. However the shorted cap ended up being the bad guy pulling the 8v to ground low. Note: I hate schematic that don’t show connection without at dot or a jump, sometimes this can confuse a person as to what trace is connected to what else. Awesome job, I felt excited like I fixed the radio along side of you! BTW, I love all of your expensive testing equipment, maybe Santa will be good to me this year like he has been to you in past, lol.
🙂👍
Thanks for the nice feed back Mike. Really glad that you like my video so much! All the best to you
Every time I Watch I Love it - the detail explanation and presentations top notch ..!!!
I first time see so clear explanation 👍, your english much better like many origin English.
Excellent video for me who have never done any faultfinding on my own yet. I learned a lot thank you for sharing.
Yann Kitson Hi Yann, glad that you like my vid. Thanks for comment!
Excellent thank you. I hope you do more of these step-by-step videos.
InTheNameOfJustice Thank you. I try my very best :-)
Excellent video and I learned something new - that electrolytics can fail short as well as the usual open, and good tip using resistor to spot where the short is. Thank you also for making this video in English.
+Kyle Morris Hi Kyle, thanks for feed-back. I'm glad that you like my videos! 73's Peter
loved this video , made easy by the way you taught us to use diagrams , thank you very much peter
Good, informative information! I'm wanting to learn basic troubleshooting and this was a nice presentation!
Just finished watching this video. Outstanding. You were very thorough with your explanations. Almost every time I thought of a question about what you were doing, you answered it! Maybe at some point, you could compile a list of your preferred sources for schematics and component data sheets. Thanks so much for taking the time to do this video!
+Mitchell Smith (KB3GKC) Hi Mitchell, thanks for comment and kind words! Well to be honest there is no list of preferred sources. I always use one of the known search engines to find the best result. That's it...73 and again thanks for stopping by!
Hello ! Electrolytic capacitors are the shortest life components in electronics and therefor they are usually responsible for most of the problems. That is why some technicians replace all of them in equipment over 10 or 12 years old. These CB models are over 20 years old, most of them, so they are ready for capacitor replacement ! Good job, you seem to be a good technician ( and with a very nice bench). Keep up the good work and the nice videos.
+CT1ELP Yes agreed, e-caps can be very nasty. Thanks for watching 73
This was the best tutorial that I have seen and you make it so easy to understand, tnx for sharing and looking forward to the next one...
Bud...
budleyca1 Hi Bud, thanks for your nice comment!
Hello Peter - Great video and process of elimination.
I very much enjoyed your video and learned lots from it. I've a similar tx problem on another radio. I will now use it as a roadmap for my own repair project. Thanks and 73's
+Colm Brazel Hi Colm, thanks for your feed-back and the best for your repair. 73
awesome video, I have a BS in electrical engineering and I am a Extra Class Ham (KK4EDE) and I have zero troubleshoot abilities, I could design a transmitter easier then fixing one, trouble shooting is really an art form, great job and I hope you do more of these type videos... the thought process that one goes through is more than half the battle.
Michael Katt Hi Michael, thanks for your feed back! It is really essential to have good service manuals, otherwise you are lost. I really would appreciate that vendors put more focus on documentation. That should really be a key selling argument!
Your by far my favorite technician to watch
Excellent video & fault finding, brilliant test set up you've got in your workshop.
Andy
A & L Appliances Hi Andy, thanks for your feed-back!
You actually made this comprehensible, even for the layman. Thanks for the video!
Thanks Bogdan for watching and feed-back. All the best and 73
great vid Peter,im ok with circuits but I no nothing about radios unfortunately, thank you for taking the time to educate us my friend.
Hi Peter, ok thank you yes it all makes sense, I don't have the radio anymore I sold it some time ago on ebay, but I was always curious about it...snowing here this morning, first snow we have had this year...look forward to more of your videos...Fred.
Really enjoyable to watch, your care and detail you took in the faultfinding was fascinating; seeing the schematic the first thing I suspected were the decoupling capacitors, but will heed your more methodical approach after many a time getting it wrong myself by using a 'blunderbuss' approach to repairs.
Hi, thanks for feed-back. I'm glad that you like my video! All the best and 73
Hi TRXBench
Sorry to say that you are completely wrong about needing a electronics background!, I am a complete novice but having watched your videos and with your amazing tutorial on this video and others, I was able to fix my President Lincoln which didn't even have the same fault.
Keep up the great work!!!!!
I would give you a million thumbs up if I could.
Justin
Justin Shears Hi Justin, okay in this case I'm okay with being wrong :-) Great that you have a use of my videos! Thanks for your feed-back. best 73 Peter
Really nice video, learning so much from your videos. No problem by the time taken to explain. Looking forward for more videos. Sorry for the other negative comments. seems that they really don't recognize the importance of basic troubleshooting.
Thanks glad that you like my videos...73
Another fantastic video, thankyou so much for taking the the time to explain your methods..
Karl Fell Thank you for your feed back.
Great video really enjoyed watching. Your videos make me want to learn more. Thanks please make more tutorials like this.
technos123 Thanks for your feed back
Vielen Danke!! Great Video. Thank you for taking the time to share with us. MFG. David.
I really enjoy these videos. Thank you
Thanks for watching
great video,you made a lot of great tips good luck with all your videos.....great job
Thank you Ray 73
I must call your approach "teaching by doing". Thanks for sharing.
+Juan Abreu Hi Juan, thanks for stopping by and comment 73
Kudos to TRX...Very, very good educational video ...THANK YOU!!!
Thank you
Very well demonstrated and explained Thank you for posting
+John Gulliver Hi John, thanks for feed back and comment 73
You are the best tech I have seen......
THANK YOU.....
Thank you for a very interesting video and I am sure we are learning a lot
Thanks for feed back
Nice video! It is more helping build my confidence and reinforcing what I should already know. Oh good, a SIP8 4558 dual op amp. That is as Japanese as they come! Roland Boss used to implement those with Roland house numbers hoping no one could fix their products. DIP8 4558s are as common as sea gulls on a garbage scow. . Cheers, happy Christmas, and 73s, KI7AQJ.
I did not hit enter for a day here, Peter. Bad mic preamp chip! $10!! Easy!
Gott Segnen Frohe Weihnachten! 73s KI7AQJ
Thanks for watching Seth and of course for you and yours happy Christmas as well! 73
Great video and good clear instruction on tracing the fault. Thanks
***** Hi John, thanks for your feed-back.
Awesome video, thank you. My radio has the same symptom/problem. 👍
now you can fix it...
Thanks for showing us the repair and hunting process. The board for the lincoln looks really nice, i have a ranger but i just can't find it right now.
Hello Carlos, the best way to test modulation is apply a sample of the mic audio to the horizontal input of a scope and an RF sample to the
vertical. The resulting trapezoid pattern will reveal not only modulation percentage, but also distortion, noise, hum flat-topping etc.
And for SSB use the pattern to adjust the balanced modulator for minimum residual carrier.
K4OF.
I enjoyed your video and I'm headed to the bench now with a 2510 that has the same symptoms . thankyou
Thank you, glad that it was helpful! 73
replaced same caps . no joy.
oops wrong channel
This was an AWESOME video! Thank you for taking the time to record and narrate it. Very informative, I will pass it on to our local Ham Radio Club members. 73's KE0EYH
+Jim Nichols Hi Jim, thanks for the nice feed-back! Take care and 73's Peter
Do U know what are u doing, an impossible work, u don't know English well like me even though u r trying to explain deeply, that is amazing, I mean amazing, I'm so exited, plz keep it up.With a lot of love n thanx.Cheers.
Thank you Abdullah! Glad that you like it! Thanks for watching 73
As usual, I enjoyed the video! Thanks, Peter, I have one of those Uniden President's that I lost the output on, so I have some work to do. 73...Dan
+Beretta96Dan Thanks you Dan and good luck with your Uniden.. 73
Very good video. Thinks for the detailed information 73s.
Joe C Hi Joe, thanks for watching!!
Great video! Very informative. The mic amp HAS to be able to switch to transmit for hands free keying or VOX.
Great explanation,thanks. I had similar problems with the President Grant: transmit/receive switching did not work, I looked for and found the first faulty capacitor, transmission worked, but was very insensitive in FM/AM, error somewhere in an intermediate stage. I didn't look any further, but replaced all capacitors (except the largest). Works great again and is very sensitive, you can hear a signal from 0.5µV.
Why not swap them all? As sets, capacitors cost me less than 2 cents per piece.
Very good tutorial.Thanks
Really great video. Please make more.
+Infinitesap Thank you! 73
Great video i worked on these several years ago and found the caps would short so there was no dc bias
Excellent job, thank you !
Thank you very much, brilliant job and extremely helpful!!
Wonderful! I believe I would need a brain transplant to be any thing like you in trouble shooting but it is good to learn to capacity any way. Thanks KI7RJS
Very nice video. Thank you for sharing!
+Brian K Hi Brian, thanks for stopping by and comment!
Just had a similar problem with a maycom em27 it had no audio on tx. I only had a circuit diagram and no board layout also it was a double sided board it was a real pain to trace without a board layout as there were no component markings on the board. service information is a big help if u have it. Great video excellent work
Gary Sanderson Hi Gerry, it is sometime a nightmare without a proper diagram. Thanks for your feed back
Thank you for your patience to teach a method and resolve problems! Can you share a video or some tips how to disassembly and reassembly a board, like this old radio. I'm go crazy with all cables and interconnections. There is a way to do properly?
The only way is to take photos with your cell phone to have a reference after repair...
Big Thumbs Up ! There you have it guys, the application of logic, coupled with fundamental knowledge of how transistors work, is used to follow ( or find !) the switched dc signal needed to enable the transmitter. I don't know where the PCB layout info came from... but it's not in the manual... but along with the data sheets on the devices, it is really an important item necessary to do this work.
+Capt Larry - Thank you Larry for feed-back! 73's
man, that is one clean looking schematic!
+Hi11ary Goddam C1itton LOL Yeah I agree :^) Thanks for watching!
Great video! When the supply voltage was discovered one side of the resistor but not the other, I assumed that the resistor had gone open circuit. Why would the voltage not drop both sides of the resistor? What made you suspect the capacitors? I was with you until then.
because the resistor was acting as a load on the +8v rail, tied to the other side, which was effectively grounded. the resistor check mainly told you where in the circuit the fault was. resistors rarely die unless they are totally fried, which is usually visually obvious.however, electrolytic capacitors die all the time and are in fact, the most common failure points of most electronics - and they very often fail as a short, which means anything on that part of the circuit is pulled straight to ground, minus whatever resistance the now shunt capacitor gives (which is why there was some minimal voltage coming across)
@@thechillhacker great, thanks for your reply Scott. Much appreciated!
Very good tutorial.
Very nice. A little slow, but thorough. Thanks!
+anydamaddress1 He goes through it very well.. and almost with the style of an instructor in university/college. In my experiences, to have the expertise is one thing, but to have the ability to teach others (who may have varying experiences), his style was perfect.
+anydamaddress1 Thanks for comment
+Michelle Pucca Thanks Michelle!
Very professional way...thanks
Thanks for feed-back Mario!
I hung in there through the whole tutorial. I am going to SAVE this one to remind me of your thought processes for tracking down the faulty components. I still need some more equipment for troubleshooting. Do you have any idea where they sell used-but-working bench equipment? Very nice tutorial and video work. 73 / Elrae / Pennsylvania / USA
Second time around. Just as good as the first. Vell done.
Love your work ...
A w2aew video also found the same problem troubleshooting a HR2510. It must be a common problem with the radio. thanks for the video
Darren Olafson Hi Darren, you are right this is a well known problem. Thanks for watching.
+TRXBench Ahhh, I wondered what made you go tracking backwards up the PTT line instead of looking at the RF driver/final section first. You've been here before in this model radio! It also explains why you zeroed in on the caps when there were several other components that could have been shorting out that power line. Checking continuity across C75 in circuit and finding a short actually wasn't very helpful, as you would have found continuity there even if the cap had been open and some other component was shorting the power line to ground as both sides of that cap would still have been grounded. I'm also curious how that 100 ohm R40 survived with nearly 8 volts across it. It should have been dissipating over 1/2W. It didn't look like a 1/2W resistor. Thanks for a great video.
Great job.😊
Thanks for the video, its very good explained, BTW you have a very nice radio lab equipement!, 73¨from XE1YZY
+Pedro Arnaud (XE1YZY) Hi Pedro, I'm glad that you like it. Thanks for comment 73
Nice job sir! Where do you get block diagrams and nice color board layouts?
Also like the beep test to see if the capacitor is shorted out.
Nice walk through - time for a complete recap on that radio (well if it was mine or the customer wanted to pay ;) )