Absolutely love that somebody wants to dial down deep into these vintage electronics. I hate to see waste and love it when somebody can make an old amp new again.
Thank you for restoring the Universe's balance. No technician should abstain from yelling obscenities when things don't work. Mark laughing about them could cause a crack in the space/time continuum, or something.
The younger generations nowadays don't worship much anything, if it's being broken, it's being trashed out, and bought new! Into the 80-90s, we've had serveral good electronics repair stores, but into 2024...go figure...most of them are all gone...sad, but true. It's simply great, to watch Marks videos.
People these days are lazy, they love convenience, they don't care about waste (or wasting their money) and the big corporations, which have created this environment, are of course more than happy to feed their own greed and supply expensive, non-repairable crap to the hungry masses.
The SU 3500 , which I sold when they were new , was 43W/channel RMS into 8 ohms , nowhere near 100W/ch . That one must have been a US import because they were never sold in the UK with black front panels . I had one many years ago , along with the matching ST-3500 tuner .
What I like about this, apart from the mad skills the dude has, is when things aren't working he's very philosophical, just chuckles and tries something else. Even when I'm attempting easy jobs I get the hump something fierce if it isn't going to plan.
It's about time you got a tricky one. I was beginning to think you only filmed the easy ones, haha! Almost all of my repairs are as bad as this or worse. Suppliers have almost given up on support for repair now so it's up to us to fix them any way we can.
@andrew_koala2974 Please accept my SINCERE apologies for OFFENDING you. I shall attempt never to comment near you again so that you do not have to put up with the filth that is my ill-educated self.
G, day Mark from Sydney Australia. I really enjoy watching your circuit board investigations, testing; * Diodes * Capacitors * Resistors * Integrity of traces and solder connections * Oscilloscopes (frequency peak to peak) two independent channels. * Flow of voltage and amperage to specific specs of each component. * Dis- assembly and assembly of cabinets ( with repair and manufacturing of controls) Thank you for your time in producing these videos, sir. 🌏🇭🇲🤨
Very nice mark. Takes me back to when I didn't have the circuit diagram and just used a multimeter to track the components and drew my own diagrams. Thanks and stay safe you and yours.
I love to watch at the slowest speed of you getting ZAPED in the opening Mark! Its a hoot to watch your reaction! Merry Christmas and love your videos! Keep up the great work.
Thanks so much. Love this stuff, for me takes me back 70's early 80's 12 years old. Cor, wish I had videos like this back then!! All I had was the local library and pestering the local tv repair shop owner...Ended up doing an electronics apprentiship and like many of us ended up in IT...
2sc4793 has high hfe and freq limit. That makes it prone to oscillation if not compensated with higher capacitance c403 and c404. It depends on how much local feedback the circuit has, whether it will be an issue. Problem is sometimes you won't see oscillation on a straight output load resistor but it can show up with an actual speaker load. I never substitute transistors on these older amps unless its been tested with an actual speaker load and measured to be sure it will last.
Love your little chuckle when you detect an obvious fault, then you explain it and instantly fix it! You are speaking a language I don’t understand, but wish I did. Ha ha! I enjoyed this vid. Thank you.
I love these videos, really fascinating. I came here after watching the Louis Rossmann video and have been working my way through your back catalogue ever since. Many thanks!
Cliff hanger....... ohhhh mannnn.... I repair stuff from time to time, nothing like you, just my own junk usually, but I would never have found that transistor with the thermal fault. I would have put it on my atlas tester, it would have probably said it was fine and I would have moved on. Brilliant job sir and great videos.
Hey, Mark, another great journey on repair, Thanks! Those three pushbuttons on front are for matching the output impedance of the phono cartridge, usually magnetic to the phono input of the amp. I still have a ton of vinyl records, especially 45s. Cheers............
I have an early 80s Harmon Kardon amplifier that has 2 phono inputs and selectors for the different cartridges, hi and low filters etc. Lovely sounding old amp. Love your videos. Keep up the good work, sir!
Mark, many years ago I discovered a really good alternative to using a multimeter to test components. It required a 'scope to display the test results but it was quick and effective. The 'scope displayed the properties of the component under an AC test current. A diode gave a right angle, a resistor a diagonal, a capacitor a circle. Subtle differences in the display revealed leaks, high ESR, etc. A great bit of kit.
it's a curve tracer, it's actually built in on some old Hameg scopes labeled as component tester. you can have any scope to display a curbe trace in X-Y mode using an ''Octopus'' circuit
@@mohsentabouna6401 No, that Hameg scope has a component signature analyzer and not a "curve tracer". Many other people mistake that as well. You saw a real curve tracer in this video @24:30, the type 576. Look at that point again. It is plotting a series of steps of operating points to display the characteristic curves of a device in current / voltage axis. A signature analyzer is looking at devices in a single operating point area. Even the DCA75 transistor analyzer that was shown in this video has an actual real low current curve tracer that you can use by USB to see the characteristic curves of devices displayed on your computer. But the DCA75 can't source enough current to be useful for matching output transistors and is only good for small signal devices. Transistors need to be tested and measured at their intended operating point in the circuit for current and voltage to find a matched pair with similar curves or to get a good reference check.
I just love this channel! 30! years after getting my AAS in Electrical Instrumentation Technology, I can follow along while you troubleshoot cool stuff. I don't work on electronics for a career. I am more of a CNC repairman and Industrial electrician, but watching you patiently go through these old amps and other audio gems brings me back to my college days. And thank you for leaving your infrequent mistakes in! We all make them, so its good to be reminded that sometimes s%*t happens, but its ok, just carry on. Cheers from Long Island, NY.
I would be ecstatic if I could get my old 70s amplifier down to -10 mV DC offset. The fact that you got that thing down to 000.33 is freaking amazing. This is a testament to the old early to mid 70s gear. And of course your knowledge and ability to do the repair!
Someone gave Mark a beautiful mind and fantastic hands. He can fix everything. He s a master. He s a celebrity of these thematic channels. And as for all the celebs we want to watch more and more: Mark at the grocery store for example, or Mark taking a boat. That would be brilliant.
Mark, you're the best, hands down! I'd love to purchase an older Sansui receiver from you if you ever come across one or have one! I've been looking for YEARS! ANYBODY???
Excellent as always, I like your honesty, others would blame faulty chips etc but not you, I've used the wrong resistor is your reply. That puts confidents in people knowing that they are dealing with an honest person, but in the same sentence, I wouldn't like to play you at cluedo, your like a real investigator, no stone is unturned.
Great video Mark, always good to see fix's are not straightforward but, by process of elimination combined with your knowledge it makes for a captivating video.
Wow been a tough one so far! I'm amazed at your ability! When you held up something black and Technics I thought I knew what was in store, but I was wrong! It was a lot older than I expected. Love the construction of that amp and how over sized and understressed it is for 100w
Those Technics Amps were gold when it came to audio equipment. I'm a product of the 70's and 80's so I remember them well. Was hoping you were going to test it by cranking up some Led Zeppelin. Technics amps were meant for listening to Zeppelin tracks. I wish those were still around new. Such an iconic piece of equipment for audio.
Made In Japan 1:31. Something we all hold very dearly in our hearts. I can't say the same for Chinese made goods, despite the many years of experience they've learned from Japan. Comes down to culture and habits or ignorance, close enough doesn't make it good enough.
Awesome! I love seeing the use of the curve tracer and how as great as the dca75 is, a real curve tracer still has its uses. I had a similar experience recently with an intermittent transistor that the 575 helped me find
For some strange reason I can’t help but keep watching your content Mark and the strangest thing is I’m not even into electrics or electronics as classic dirt bike motorcycles is my bag but you certainly know your stuff and are far to intelligent for the likes of me to try and decipher what the hell your on about when you get technical and start talking ohms and other stuff, but a great channel and interesting content keep it up.
Mark, I can relate to your repair work on newer and vintage electronics. Had that happen to me, find the problems only to have something else needed fixed, when you think it's all fixed and then find out you screwed up something. Can't wait for your next video on what happen to the Technics stereo amplifier.
Mark, love your videos, but you've certainly got to change your name to "the Jolly Fixer"! Love how you're always chuckling during your repair - quite the opposite of my efforts; constantly cursing ;) All the best mate!
These videos of yours are at the top of my list for 'handling real world examples' because of your presentation, documentation and editing. Also it sounds like you are using a venturi de-soldering, which is something I've only imagined before. I did build a similar device for killing poisonous spiders long ago (equally effective), but it's comically enormous for electronics de-soldering (1.5 meters long).
I always understood the 13A fuse was to protect dead shorts in the cable, and most hifi has a mains glass fuse rated correctly for the device. So the glass fuse is the device protection really, and non UK versions won't have any such fuse in the plug. Also, the ceramic sand fuses only go down to 3A which would still be too high a rating for many amps. Great vids, thanks Mark!
In a Japanese amplifier, I have seen a plastic transistor become intermittant and put the entire supply voltage on the speaker. Several angrily placed taps with my Widlarizer rapidly changed it's geometry.
I always look forward to seeing your videos - totally absorbing to watch. It’s almost worth me blowing something up just to see you repair it. Great stuff Mark👍🏻👍🏻👍🏻👏🏻👏🏻👏🏻
I'm a big fan of your videos, I never seen so much attention and care for the details. Your dedication is far beyond to what an equipment owner usually expect. For not tell anything about amazing sense of humour, maybe the most happy technician around the globe.
The stereo mode switching is probably great for those 60’s mixes that have instruments/vocals hard panned. The L+R mono would stop you having Jimi coming out of one side, the drums out of the other… Or the individual L or R mono modes would let you isolate the hard panned instruments.
If I recall correctly one of the argument for that switch (which was popular on amps of the period) was that you could use two amps as individual mono blocks and double the power.
Mark i just really enjoy your repair videos. I still don't understand how you are able to keep track off all those screws taking apart all this stuff ;) Cheers!
I don't have a transistor tracer, but i have one of those old Sencore Cricket testers. It tests the transistor as an audio amplifier with a beep and reads out gain and leakage in a meter. Pretty quick to use. You don't have to worry about the lead configuration, as you merely turn the main rotary switch around until you get the readings. Of course it's best to just know the correct config, but if you don't, it will show the correct configuration.
Great vid Mark. I owned one of these back in the day and loved it. I have also repaired a few. It was much easier back then because all the semiconductors were available from Technics. It has reminded me that I must get round to repairing my old Sugden power amplifier and pre-amp unit. It's only been broken for about 12 years, so no rush! Incidentally, I have 2 sets of the Sugden test equipment, low distortion signal generator, AC millivoltmeter and distortion analyser, don't know if you've come across them or remember them. I live in Huddersfield and Sugden were based just a few miles away in Cleckheaton, so a lot of old Yorkshire engineers used to have these. The sig gens are quite amazing for their day at 0.02% THD as I recall.
I love watching your videos and I wish I had your skill and knowledge!. My family also like to watch even tho they aren’t particulary interested in electronics. You are so positive and it affect us all😊
looking at those diagrams is like looking at a wizards spell book, i was an engineer and can read any drawing, but this stuff is like magic i love it !
hello, very nice video, it's a shame that I don't understand English when I'm watching. I learned a lot from you, the problem shift is not in electronics but also in passive mechanics. keep filming and take care master. Luboš. Czech.
Love the channel, great stuff! When it comes to working on these power amps is there a set process you have for discharging anything, large caps spring to mind. I like the Idea of trying to fix an old amp but the HV components scare me 😂
Brilliant video and and you explain so well. I'm only a hobbyist but as I teach myself I watch your videos and slowly the stuff you don't explain in your choices I am answering it myself. You would make a very good teacher and you convey brilliantly the practical application on the bench of just repeating the basic questions of simple circuits. It years and a long time to have the faith on the meters to actually repair stuff as you do, but it's good to see great knowledge applied and make it accesable for the journey. Inspiring stuff mate x
I always follow your work, I'm passionate about electronics here in Brazil and it's very rare to repair older devices, congratulations on the work......beautiful bench, my dream, God willing, with my oscilloscope....
very cool Technics - it has options that my Crown IC 150A has on it.. I love the ability to tune each channel frequency and quick reverse stereo or mono dial ..but the Crown is a Pre-amp super clean .
I know next to nothing about electronics, but these videos are captivating. Mark's knowledge plus his pleasant demeanor keeps drawing me in. 😀
You will eventually learn!
@@hernancoronel I used to know Ohm's Law. Maybe that will help. 😀
@@Flavum It will eventually wear down your resistance. You might even meet a few cool conductors along the way.
I agree with you. I have a basic understanding of electronics, but Mark makes it more accessible.
Doesn't he just...It's years of experience right before your eyes. Can't learn that from a book....
I'm an old troubleshooter of electronics from the 80's. I miss those days and I relive them through these videos. More please ...
Same repair tech 80's - 2000 it brings back memories for me too.
You are a liar and a fantasist.
Same here.
Same here.
This is my new favourite channel
Absolutely love that somebody wants to dial down deep into these vintage electronics. I hate to see waste and love it when somebody can make an old amp new again.
The suspense! Fascinating work Mark!
I like playing a game in my head - Everytime Mark laughs when something doesn't work, I yell obscenities. Love the content Mark!
Thank you for restoring the Universe's balance. No technician should abstain from yelling obscenities when things don't work. Mark laughing about them could cause a crack in the space/time continuum, or something.
Mark is a Laughing Buddja with the sweetest smile !! Well done on the beautiful moulding !!
The younger generations nowadays don't worship much anything, if it's being broken, it's being trashed out, and bought new! Into the 80-90s, we've had serveral good electronics repair stores, but into 2024...go figure...most of them are all gone...sad, but true. It's simply great, to watch Marks videos.
People these days are lazy, they love convenience, they don't care about waste (or wasting their money) and the big corporations, which have created this environment, are of course more than happy to feed their own greed and supply expensive, non-repairable crap to the hungry masses.
I'm blown away with your test equipment. It's a great video 👍
The SU 3500 , which I sold when they were new , was 43W/channel RMS into 8 ohms , nowhere near 100W/ch . That one must have been a US import because they were never sold in the UK with black front panels . I had one many years ago , along with the matching ST-3500 tuner .
Mark, you're Wonderful. You've Won the Watson Watt Outstanding achievement award !
What I like about this, apart from the mad skills the dude has, is when things aren't working he's very philosophical, just chuckles and tries something else. Even when I'm attempting easy jobs I get the hump something fierce if it isn't going to plan.
The Towers International Transistor Selector ... wow, you've brought back memories! I've not seen that for .... many decades!
These videos are so soothing, restores my faith in humanity
You really got me with that cliffhanger! Can't wait to see what happens next, love your videos!
It's about time you got a tricky one. I was beginning to think you only filmed the easy ones, haha! Almost all of my repairs are as bad as this or worse. Suppliers have almost given up on support for repair now so it's up to us to fix them any way we can.
@andrew_koala2974 Please accept my SINCERE apologies for OFFENDING you. I shall attempt never to comment near you again so that you do not have to put up with the filth that is my ill-educated self.
@andrew_koala2974 Nice example of pedantry
Nothing EASY about any of these repairs
@@BryantBrothers-gm1qx he makes it look easy or is it that hes at ease with the work:)
@andrew_koala2974lol imagine getting this angry and sanctimonious about a TH-cam comment
Always a pleasure Mark! Looking forward to your next. Cheers!
Mark, you really know your stuff, and you got all the fancy tools that help!
The SU3500 is a super amp. Rated at 43W into 8 ohm and capable of driving 4 ohm loads with ease. Did a full recap on mine and it sounds wonderful.
А есть люди, которым не нравится его звук.
When in doubt recap it out😅
A mend it Mark video on a Monday evening. What a treat.
Interesting amp there and what a cliff hanger.. can't wait for the next episode
G, day Mark from Sydney Australia.
I really enjoy watching your circuit board investigations, testing;
* Diodes
* Capacitors
* Resistors
* Integrity of traces and solder connections
* Oscilloscopes (frequency peak to peak) two independent channels.
* Flow of voltage and amperage to specific specs of each component.
* Dis- assembly and assembly of cabinets ( with repair and manufacturing of controls)
Thank you for your time in producing these videos, sir.
🌏🇭🇲🤨
Great stuff Mark, very entertaining. Wish you could fix my 90's Technics stuff.
Woohoo! I'm such a fan, thrilled to see a new video from you. Thanks for sharing your knowledge.
Great work! Waiting for the missing knob replacement!
I like your smile and positive attitude throughout your repairs, even when things get difficult you never swear or anything
Oh yes he does lol it's what we all sit on the edge of our seats waiting for #*@& 🤬
I was missing your videos Mark! Regards from Brazil 🎉
Very nice mark. Takes me back to when I didn't have the circuit diagram and just used a multimeter to track the components and drew my own diagrams. Thanks and stay safe you and yours.
I love to watch at the slowest speed of you getting ZAPED in the opening Mark! Its a hoot to watch your reaction!
Merry Christmas and love your videos! Keep up the great work.
Thanks so much. Love this stuff, for me takes me back 70's early 80's 12 years old. Cor, wish I had videos like this back then!! All I had was the local library and pestering the local tv repair shop owner...Ended up doing an electronics apprentiship and like many of us ended up in IT...
Beautiful amp! Great repair! Thanks Mark and i hope you are doing well!
It is always a treat when you release a new video Mark and you really didn't disappoint with this one!
Can't wait for the next installment.
2sc4793 has high hfe and freq limit. That makes it prone to oscillation if not compensated with higher capacitance c403 and c404. It depends on how much local feedback the circuit has, whether it will be an issue. Problem is sometimes you won't see oscillation on a straight output load resistor but it can show up with an actual speaker load. I never substitute transistors on these older amps unless its been tested with an actual speaker load and measured to be sure it will last.
Agreed, also MJE350 is very slow...
Love your little chuckle when you detect an obvious fault, then you explain it and instantly fix it! You are speaking a language I don’t understand, but wish I did. Ha ha! I enjoyed this vid. Thank you.
I'm going to use "knackered" for something. As always, great video, Mark.
Great work as usual a master in electronics can’t wait to get my device back. 👍
That was a tricky one, Mark. Thanks for sharing. Looking forward to seeing if the repairs worked...
Great vid Mark. The golden age of Technics amps.
I love these videos, really fascinating. I came here after watching the Louis Rossmann video and have been working my way through your back catalogue ever since. Many thanks!
Cliff hanger....... ohhhh mannnn.... I repair stuff from time to time, nothing like you, just my own junk usually, but I would never have found that transistor with the thermal fault. I would have put it on my atlas tester, it would have probably said it was fine and I would have moved on. Brilliant job sir and great videos.
Hey, Mark, another great journey on repair, Thanks! Those three pushbuttons on front are for matching the output impedance of the phono cartridge, usually magnetic to the phono input of the amp. I still have a ton of vinyl records, especially 45s. Cheers............
Cliff-hanger! Great repair and I love the modular construction!
I have an early 80s Harmon Kardon amplifier that has 2 phono inputs and selectors for the different cartridges, hi and low filters etc. Lovely sounding old amp. Love your videos. Keep up the good work, sir!
Mark, many years ago I discovered a really good alternative to using a multimeter to test components. It required a 'scope to display the test results but it was quick and effective. The 'scope displayed the properties of the component under an AC test current. A diode gave a right angle, a resistor a diagonal, a capacitor a circle. Subtle differences in the display revealed leaks, high ESR, etc. A great bit of kit.
it's a curve tracer, it's actually built in on some old Hameg scopes labeled as component tester.
you can have any scope to display a curbe trace in X-Y mode using an ''Octopus'' circuit
@@mohsentabouna6401 No, that Hameg scope has a component signature analyzer and not a "curve tracer". Many other people mistake that as well. You saw a real curve tracer in this video @24:30, the type 576. Look at that point again. It is plotting a series of steps of operating points to display the characteristic curves of a device in current / voltage axis. A signature analyzer is looking at devices in a single operating point area. Even the DCA75 transistor analyzer that was shown in this video has an actual real low current curve tracer that you can use by USB to see the characteristic curves of devices displayed on your computer. But the DCA75 can't source enough current to be useful for matching output transistors and is only good for small signal devices. Transistors need to be tested and measured at their intended operating point in the circuit for current and voltage to find a matched pair with similar curves or to get a good reference check.
I just love this channel! 30! years after getting my AAS in Electrical Instrumentation Technology, I can follow along while you troubleshoot cool stuff. I don't work on electronics for a career. I am more of a CNC repairman and Industrial electrician, but watching you patiently go through these old amps and other audio gems brings me back to my college days. And thank you for leaving your infrequent mistakes in! We all make them, so its good to be reminded that sometimes s%*t happens, but its ok, just carry on. Cheers from Long Island, NY.
These technics amps get a slating by some folk, but this seems pretty well laid out...
Great video 👍
Kind regards from Turkey 👍🇹🇷
I would be ecstatic if I could get my old 70s amplifier down to -10 mV DC offset. The fact that you got that thing down to 000.33 is freaking amazing. This is a testament to the old early to mid 70s gear. And of course your knowledge and ability to do the repair!
Someone gave Mark a beautiful mind and fantastic hands. He can fix everything. He s a master. He s a celebrity of these thematic channels. And as for all the celebs we want to watch more and more: Mark at the grocery store for example, or Mark taking a boat. That would be brilliant.
Mark taking it up the back passage?
Mark, you're the best, hands down! I'd love to purchase an older Sansui receiver from you if you ever come across one or have one! I've been looking for YEARS! ANYBODY???
Excellent as always, I like your honesty, others would blame faulty chips etc but not you, I've used the wrong resistor is your reply. That puts confidents in people knowing that they are dealing with an honest person, but in the same sentence, I wouldn't like to play you at cluedo, your like a real investigator, no stone is unturned.
Fascinating process for the trouble shooting, but also an amazing but tedious job of setting and resetting camera angles!
Great video Mark, always good to see fix's are not straightforward but, by process of elimination combined with your knowledge it makes for a captivating video.
You make everything look so easy .. we viewers feel very helpful too 🙂
Really enjoyed this. One of the better fix it editing I've seen. Love your little chuckle too Mark, lol.
Wow been a tough one so far! I'm amazed at your ability! When you held up something black and Technics I thought I knew what was in store, but I was wrong! It was a lot older than I expected. Love the construction of that amp and how over sized and understressed it is for 100w
Great video, even greater news there is a second installment coming.
Those Technics Amps were gold when it came to audio equipment. I'm a product of the 70's and 80's so I remember them well. Was hoping you were going to test it by cranking up some Led Zeppelin. Technics amps were meant for listening to Zeppelin tracks. I wish those were still around new. Such an iconic piece of equipment for audio.
Ahhh YES! I cherish these repair vids!
Made In Japan 1:31. Something we all hold very dearly in our hearts. I can't say the same for Chinese made goods, despite the many years of experience they've learned from Japan. Comes down to culture and habits or ignorance, close enough doesn't make it good enough.
Thoroughly enjoyed this video - great work Mark!
There is always a small dead transistor hiding somewhere ;) Tricky one ! Perfect job.
I really love to see the way you work.........
Note: the 2SC4793 is an obsolete part. You can use a MJE15034G - cost about $1.50 U.S.
Thanks!
My goodness you have to have the patience of a Saint sometimes in this job!
Awesome! I love seeing the use of the curve tracer and how as great as the dca75 is, a real curve tracer still has its uses. I had a similar experience recently with an intermittent transistor that the 575 helped me find
That is such happy restoring! Nice job!
great Mark, can't wait to see part2
For some strange reason I can’t help but keep watching your content Mark and the strangest thing is I’m not even into electrics or electronics as classic dirt bike motorcycles is my bag but you certainly know your stuff and are far to intelligent for the likes of me to try and decipher what the hell your on about when you get technical and start talking ohms and other stuff, but a great channel and interesting content keep it up.
Like watching a mix of dogged detective, electronics Guru, gifted artisan and cheery friend.....just great!❤
Mark, I can relate to your repair work on newer and vintage electronics. Had that happen to me, find the problems only to have something else needed fixed, when you think it's all fixed and then find out you screwed up something. Can't wait for your next video on what happen to the Technics stereo amplifier.
Mark, love your videos, but you've certainly got to change your name to "the Jolly Fixer"!
Love how you're always chuckling during your repair - quite the opposite of my efforts; constantly cursing ;)
All the best mate!
Cheers Mark really enjoyed the video, can see from all the cuts a lot of work goes into the video editing. All the best.
A pleasure to watch your expertise.
These videos of yours are at the top of my list for 'handling real world examples' because of your presentation, documentation and editing. Also it sounds like you are using a venturi de-soldering, which is something I've only imagined before. I did build a similar device for killing poisonous spiders long ago (equally effective), but it's comically enormous for electronics de-soldering (1.5 meters long).
I always understood the 13A fuse was to protect dead shorts in the cable, and most hifi has a mains glass fuse rated correctly for the device. So the glass fuse is the device protection really, and non UK versions won't have any such fuse in the plug. Also, the ceramic sand fuses only go down to 3A which would still be too high a rating for many amps. Great vids, thanks Mark!
In a Japanese amplifier, I have seen a plastic transistor become intermittant and put the entire supply voltage on the speaker.
Several angrily placed taps with my Widlarizer rapidly changed it's geometry.
In that case you should have diffused its junction around the whole workshop.
I'm really impressed, you looked at a circuit on a board and then drew it out....
I always look forward to seeing your videos - totally absorbing to watch. It’s almost worth me blowing something up just to see you repair it. Great stuff Mark👍🏻👍🏻👍🏻👏🏻👏🏻👏🏻
You explained everything very well, Mark. That's what I expected. Bravo, thank you.
I'm a big fan of your videos, I never seen so much attention and care for the details. Your dedication is far beyond to what an equipment owner usually expect. For not tell anything about amazing sense of humour, maybe the most happy technician around the globe.
The stereo mode switching is probably great for those 60’s mixes that have instruments/vocals hard panned. The L+R mono would stop you having Jimi coming out of one side, the drums out of the other… Or the individual L or R mono modes would let you isolate the hard panned instruments.
If I recall correctly one of the argument for that switch (which was popular on amps of the period) was that you could use two amps as individual mono blocks and double the power.
@@SierraLimaOscar Ah yeah that makes a lot of sense!
It's also great for when some muppet youtuber takes an unnatural liking to one channel or the other.
@@godfreypoon5148 That *my left ear loved this video* issue seems less common now, think it must’ve been a video editing/codec issue.
love the repair vids please keep doing them.
Thank my lucky stars !!!! Another mend it Mark video !!!!! Best Monday ever !!!!!
Mark i just really enjoy your repair videos. I still don't understand how you are able to keep track off all those screws taking apart all this stuff ;) Cheers!
I don't have a transistor tracer, but i have one of those old Sencore Cricket testers.
It tests the transistor as an audio amplifier with a beep and reads out gain and leakage in a meter.
Pretty quick to use. You don't have to worry about the lead configuration, as you merely turn the main rotary switch around until you get the readings.
Of course it's best to just know the correct config, but if you don't, it will show the correct configuration.
So nice, amazing troubleshooting 👍👍👍
Greetings Alexander
That was quite the mystery from Mark - The Electronics Whisperer (y) Thank you very much! I understood nada, but really enjoyed it 😁
Great vid Mark. I owned one of these back in the day and loved it. I have also repaired a few. It was much easier back then because all the semiconductors were available from Technics. It has reminded me that I must get round to repairing my old Sugden power amplifier and pre-amp unit. It's only been broken for about 12 years, so no rush! Incidentally, I have 2 sets of the Sugden test equipment, low distortion signal generator, AC millivoltmeter and distortion analyser, don't know if you've come across them or remember them. I live in Huddersfield and Sugden were based just a few miles away in Cleckheaton, so a lot of old Yorkshire engineers used to have these. The sig gens are quite amazing for their day at 0.02% THD as I recall.
I'm a vintage tech and worked on valve and transistor and digital gear since the 70s. This guy knows what he is doing
I love watching your videos and I wish I had your skill and knowledge!. My family also like to watch even tho they aren’t particulary interested in electronics. You are so positive and it affect us all😊
looking at those diagrams is like looking at a wizards spell book, i was an engineer and can read any drawing, but this stuff is like magic i love it !
hello, very nice video, it's a shame that I don't understand English when I'm watching. I learned a lot from you, the problem shift is not in electronics but also in passive mechanics. keep filming and take care master. Luboš. Czech.
Love the channel, great stuff!
When it comes to working on these power amps is there a set process you have for discharging anything, large caps spring to mind. I like the Idea of trying to fix an old amp but the HV components scare me 😂
I'm still at the office but wanted to give you a like and a comment. I'll finish watching later this evening.
This amp and the tuner that went with it were in the same look as a reel to reel tape recorder RS 1500 US. When stacked together, they looked amazing!
Brilliant video and and you explain so well. I'm only a hobbyist but as I teach myself I watch your videos and slowly the stuff you don't explain in your choices I am answering it myself. You would make a very good teacher and you convey brilliantly the practical application on the bench of just repeating the basic questions of simple circuits. It years and a long time to have the faith on the meters to actually repair stuff as you do, but it's good to see great knowledge applied and make it accesable for the journey. Inspiring stuff mate x
Great video and great repair,
I'm not far away from you, in Penn!
I always follow your work, I'm passionate about electronics here in Brazil and it's very rare to repair older devices, congratulations on the work......beautiful bench, my dream, God willing, with my oscilloscope....
Learning as much as I can. Thanks for the videos!!!
very cool Technics - it has options that my Crown IC 150A has on it.. I love the ability to tune each channel frequency and quick reverse stereo or mono dial ..but the Crown is a Pre-amp super clean .