Vintage Sunmark AM FM Transistor Radio Repair A Tough One To Diagnose
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- Опубліковано 7 вер 2024
- A challenging diagnosis of the AM band in this old portable transistor radio. Bad electrolytic capacitors as usual but then so much more to get it fully functional.
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"I have a really cool resurrection tv set on the bench that I'm afraid will turn to dust if I move it"
You really know how to get us excited
1:28
The apparent oxidation on that tiny tubular capacitor actually *did* look like silver-mica disease. Even though this was a low-budget receiver, I believe this was *more than* worth the effort because of Shango's ability to demonstrate his formidable troubleshooting skills. Through methodical trial-and-error, he logically deduced it down to this tiny component.
I object your honor! That calls for speculation on Mr. Mason’s behalf. What are Mr. Masons qualifications? Has Mr Mason proven himself a qualified expert in the field of electronics? How do we know the capacitor didn’t fail BEFORE silver mica disease set in? Your honor,I request that Mr Masons comments be stricken from the record until such time that he can provide this court with adequate proof qualifying him as an expert in the field!
Sorry,Just kidding! ,I agree completely with you. I saw your Perry Mason profile photo and couldn’t resist playing “Hamilton Burger” for laughs. I should know after all these years that Perry Mason is always right.
@@Suddenlyits1960 LOL! Both of our profile images and your UA-cam handle are *definitely* period-correct regarding the Prosecution's statement!
@@chetpomeroy1399 Thats true! I had just watched Perry Mason the other day on one of my predictas.. The episode had Noah Berry jr and Strother Martin in it. Noah Berry jr was accused of marrying a woman and then killing her to inherit her estate. It was odd to see him in a role like that after years of seeing him portray Joseph “Rocky” Rockford, Jim Garners dad on The Rockford Files. He was always trying to talk “Jimmy” out of his dangerous job and into truck driving.
"capacitors exceed value of radio when new" That really cracked me up!
Thanks Shango066 for sticking with it until you figured out the problem. I have actually seen this problem before more than once. The silver paint on those dog bone caps actually oxidizes away, reducing the capacitance which, in your case, caused the IF to oscillate (as verified by the squealing). Even though those IF transformers are so low cost, the quality is surprising good (when they are new of course). The internal capacitor is actually matched to the coil's temperature characteristics, resulting in minimum temperature drift in the finished product. The coil Que is also surprising good for how small coil is.
My weekend's happiness is directly proportional to the lenght of your videos.
Always waiting for them to arrive on Sats and Suns to relax in the couch with a cup of tea and just forget about the past and the future (your videos make me achieve what meditation just cant't).
Gratitude and admiration! You are generating much more than you think out there.
Thanks! Good Karma for you :)
Shango, thank you for taking this repair to completion. I admire your skill and patience to root out this sort of problem. Who would have thought that such a cheap radio would yield such a great learning experience.
Party on, my friend.
-Chaos
and I would like to thank you for your comment that you have said just what I would like to say.. this man skillful and amazing professional man he deserves all our respect and appreciation.
Whenever the radio was squealing, a bunch of mosquitos started to gather around me & started biting me from head to toe. If I get malaria, that’s on you Shango !
The chrome/nickel pin holed speaker grills were really cool 😎
Good job. Super educational. Thanks for posting this. Loved the "I Did That !" easter egg.
Cap wizard saves you time! I like mine. Even though this was a Hong Kong radio at least they did take the time to put insulating tubing on all of the resistors and cambrick tubing coming from the antenna coil. There were at least was an effort at some level of quality. Many later sets just use paint over the resistor leads.
I really enjoyed this one. As a bonus, I’ve got a Hong Kong radio with a similar circuit, and you explained how the FM and AM circuits work in it too. I’ve got the schematic, but since I’m new to this I found it confusing.
Hey 👋, Shango066!! Almost 😅 like 👍 a pocket TV 📺!! That sucker’s packed with GREAT 👍 capacitors. Although they need replaced, this is a fantastic Japanese radio 📻. It looks like 👍 some pride went into it. I like 👍 the aluminum speaker 🔊 grille. Give it a squirt spritzer!! Your friend, Jeff.
One teeny tiny 167pF crapped out capacitor can ruin your whole day. Took a big dose of frustration,skill and patience to
get this sucker working again. Reminds me of 1950's era IF transformer SMD but with a modern IF transformer. Quite the detailed learning experience for the viewers. Many would have thrown in the towel and chucked it in the bin. You got it
fixed and it sounds great.
The subtle cues as to the 'cut of your jib' 10:25 are a constant source of humor, Shango. And relief!
I really enjoy your in depth troubleshooting. I have never seen someone go as far as to use relacementcans in the IF to prove out a belief! Keep it up!
10 transistors, 4 diodes and 50 bodges
Looks assembled with care. Careful use of insulative sleeves. And not even completely dead. I believe Radio Shack sold a version of this board. I bought it in the 70s.
Your jibber jabber still made more sense that the one standing at the podium with the seal. I really enjoy the videos. I learn while being entertained. You make it fun.
Wow, I sat through the whole thing and I barely know anything about electronics.... You just make it interesting somehow Shang! 🙂
I enjoy all your videos, but this was one of the best. Your a smart guy finding that fault, it doesn’t matter that it’s only a cheap radio. I learned from it Regards Mike 🇬🇧
One of the best radio repair videos you've made.
The repair went so well the sound even turned into stereo right at the end... :)
Your unmatched perseverance paid off on this one! Most people would give up and strip the thing for parts if a recap didn't fix the problem. Thanks for the circuit description and alignment. Those help a lot with my understanding, too.
It’s amazing the amount of different am/fm turds out there! Those little radios stank with brand new parts when they were made in the 1970’s!
Shan go, you are the man! Love your patience and show! Thanks for all your hard work and great humor throughout:)
I really admire your tenacity to repair this radio, Shango!
Sure do enjoy my time being educated/entertained by Shango.
I love it when a new Shango video hits my feed. The first thing I do is click the Like button. Then I look at the length. I saw this was over an hour so I knew Shango was going to be challenged. Shango’s OCD really kicked in on this one. Great great video! 🎉❤
One of the best fault finding videos I've seen on transistor radios with weird oscillator faults. Definitely worth bookmarking.
No one can touch the "gloved one" with his extraordinary powers! Another fine "plumbing" job! Enjoyed watching!!!!! Thanks..
I have no idea what you're doing but thank you for the pleasure of letting us watch your talent at work. Just fun stuff. 😊
43:34 Wow, i'can't belive you find those parts in my country, good to know. And yes, those yellow things are crystals for 455 MHz IF for more modern "chinko-dwinkler" radios and all kind of TV remote controls :p
Wow wow excellent resurrection. I never had/ thought those encapsulated capacitor could go wrong.
Pronounced Bull-O-Va . They made nice watches at one time. That was 60 years ago when my Grandfather had one among his watches. Argentinean parts, imported by the Nazi's from Europe... JK, probably came from the far east long ago, maybe. Love the diagnosis on this challenging Sunmark Hong Coidial way to stick it out there Shango my man! Cheers !!
Pretty & tiny nostalgic radio. I like it very much! It is still alive and well preserved!
shango066, The only radio repairman who manages to make the broadcast band sound like the dentist's drill 😅
Man you would not believe what that squeal does to my hearing aides! BTW thanks a million for this video, I have a recently acquired Sharp AM/FM transistor that had a leak that was so bad even the antenna for the FM is frozen all the copper wires have corroded and the battery case is so bad that I have removed it and replaced it with one 4.2 V Lithum battery that seems to replace the 6 volt system that used to power it. The FM is pretty dead on it so this will help with my troubleshooting on that problem even though we only get one AM and one FM station in our little corner of God's Country here in South Dakota.
Shango, ever thought of just getting some chip capacitors? They are small enough to tack in across the dead cap,
I'm thinking he just did that a couple videos ago... The Russian radio?
Its never a good idea to parallel good part with a bad one(bad cap can fail dead short)
I like the miniature dim bulb 💡 for current limitation protection.
Thanks for going the extra mile on this one. I feel like you just fixed my Philco T500-124.
Great stuff! I pretty much live for these videos - lather, rinse, repeat until Saturday and/or Sunday when the next installment airs.
Just another Shango006 spectacular and educational learning experience. The phone video was actually pretty D@mn good. Close ups were exceptional! Thanks for all you do for your subs and take care!
Another triumph for Captain Shangoo - Fantabulisticrustacious!!
Hi Shango0. Thank you for another cool Sunday video. Never had a radio act like that before. All my best.
an excelnt repair. though i am at a loss to understand why a fault in the first IF would cause the osc to stop working. glad you were able to fix it
Shango066 - You are a radio and tv Sherlock Holmes 👍 I really like your humor.
Excellent "all the way" repair!
I love those sweet radio sounds in my headphones 🎧😍
Excellent Video. Love the new stickers on the Cap wizard. LOL
Really enjoy watching your diagnostic skills and I am learning from them too. Thank you!
Outstanding video. As always Shango, I have learned so much. Thank you for another great ride!
Circuit Bending with Shango066! Those are wonderful sounds! Super hi-fi squeals! Love it
That radio probably is way more sensitive and selective than it ever was since it's meager beginning. Maybe it's utilizing all 10 transistors now! Another repair challenge well done!
Well done finding that little cap!
I once troubleshoot a no audio radio with Freeze spray. Found it worked when I hit one of the black open caps when cold. I squeezed it with pliers and started to work. I was a rookie and left it and it worked...
Maybe the oscillator frequency jumps into the signal (reception) frequency, if bad rotor contact for example, Sounds like that. You don't give up easily, you'll fix this one also. Big fan of your page for many years!
I did that... LOL nice! I love it!
I've had one of those plastic adjuster drivers for a while now. It's stamped "General Electric". I didn't know what it was besides something to do with electronics. Now I know!
I would never guessed it is the yellow IF can (more precisely the tubular capacitor). I have seen those IF cans on ebay, the shipping cost prevented me to buy any of them.
Nice challenging repair!
I love the filming with the phone, the zoom is amazing.
The sound is way better too, maybe because you are getting closer to the phone.
Fond of those "I did that" stickers. They're everywhere here....especially on the gas pumps.
Excellent find on that I F cap. Makes sense....something in the I F that prevents oscillation has to be something in the I F circuitry. But it takes a master to arrive and find it. Again....EXCELLENT FIND. Always enjoy.
Great video and a nice dig. I had to show that to the XYL. I saw one on a pump here in CT. 73 Leo
OMG, What an utter pain in the arse to work on. Great job at fixing it.
I think its a very attractive design. I LIKE IT!
made the mistake of not paying attention to capacitor polarity on a 1970s japanese multiband radio myself, the thing was drawing over 1 amp DOH! changed the caps round and it worked, i'm amazed there was no other damage luckily.
what a challenge and wow I learned so much I cant thank you enough for your time. This was very enjoyable to watch It will help me on my repairs. There is hope that it can be fixed. Your my favorite to watch. Enjoyed it more than you know.
8:55 "I finished my kit radio! Check out my work!"
Stunning work, BOSS!
Wow! Even have FM today!
Sometimes components can go bad with unwanted rectification diode like behaviour introduced into the circuit throwing dc bias causing this very problem, diodes were invented by accident when whiskers of certain tin would create rectification it is a junction problem, could be caused by a bad cap or even a some types of resistor, or dry jointed solder joint. That carbon on one end means material is being deposited on the black end, like happens with battery plates ionisation from rectification.
8:30 That's an impressive looking speaker for a near-pocket radio; maybe it will sound lost bearable once everything is in spec. I wasn't expecting the bird's nest on the solder side of that board since the top looked fairly neat.
38:57 That's a cute little thing; it almost resembles a chipmunk.
as always very interesting
Great video as always .Would never have known you were using your phone. Looks fantastic.
9:50 . . . *"I DID THAT!"*
I thought it was the tuning capacitor at first. I never thought it would turn out to be silver mica disease
Great video, amazing repair
i don't even understand what you do. i just like you're attitude.
That was a good one. Not that your others aren't.
Excellent, these capacitors are mostly damaged.
Is there anyway to diagnose these internal transformer capacitors without removing the transformer? I purchased a Grid Dip meter a while back thinking it would be a valuable asset for working on transistor radios until I realized the the transformers are shielded😬. It does help out with the antenna circuit though. I always learn so much from these videos. Thanks Shango!
Yes sir your Sunmark transistor radio is repaired and ready to go,,,,,,,, that'll be $1170.00 ....
Muito bom!!! o seu desempenho técnico .....
I enjoyed this video . Seems those I.f cans are a problem now due to there age . I learn alot from watching your videos. I'll use alot.of your tips in my own repairs . Looking forward to the next video
That was a nice one !!!
A picture-taking, video-recording camera without a pause feature is criminal. Pause is a basic feature it must have!
A Xicon datasheet for these types of IF transformers state that the internal capacitor is 180 pF. It seems to me that it should be OK to use 180 pF and adjust the core.
Pretty dang impressive.
Excellent video as always. I have a query though..why does the IFT's cap being bad cause the oscillator frequency to not change? Since the IFTs job is to just select the IF and pass it onto the next stage. Isn't the oscillator tuned circuit seprate, so I would have expected that the oscillator frequency would be changing correctly but the IFT would have not been passing it on.
Bravo.....ti seguo sempre
Hitachi sold some of their gear under the Sun Mark brand.
The phone video looks fine to me. If it makes pausing/ light video editing easier for you, I think you should continue using it. Thanks for doing these videos for us.
Man, if I saw those traces, I would give up within a second.
Is that really how things worked back then??
Wish I had your skills Your the last of the last who knows how to do stuff like this.
Excellent !!!
that was interesting. thanks!
Great job on the diagnosis and repair. It might seem like a waste, but there are people who have a lot of sentimental attachment to their old transistor radios and would have problem putting 10 hours and $20 in parts into one.
Shango is it normal for a radio like that to have so many caps? Don't think i've ever seen anything like it before. Thanks for the videos every week.
Thanks!!!
I have a small Sangean radio that I listen to a few times a week. It's so old that I bought it at Fry's in Manhattan Beach, where I spent many thousands of dollars upgrading my PC's for twenty years.
I can't help wondering how long my capacitors will keep working.
Shango Rules!!! 🍻
@@TheMikeMan777 I am buddy, I think I've seen just about every video.
Some of them I've watched a few times, but I figure a guy still likes to
hear it.... LOL Cheers! 🍻