UPDATE: So I’m running a 3-part LIVE workshop that takes us on… A Time Travel Through Vintage Electronics. We’ll rewind the clock, dive into the tech of the times… (and study the very history of how things were broken and repaired has evolved) The workshop is coming soon, but if you're reading this then you're in luck (or not)... And there's still time for you to sign up using the link below: www.menditmark.com/mend-mark-workshop The workshop dates are mentioned in the link above too.
Is there anything that you don't look forward to more than a new Mark video? Keep them coming please!! Also, it would be great to hear how you gained your knowledge. Electronics, chemical, mechanical, you know it all!
I don't know if anyone else notices the superb editing & audio on Mark's videos? Just the little touches like changing the sine audio level as it's varied on the amp, sublime.
I recognise that amp as one from Birmingham Repotory theatre. It came into where I was working at hte time for service. The initials JD belonged to John Deakin one of the service technicians. A long time ago in the seventies. He has since passed away sadly.
I knew John quite well. He did most of the large heavy audio equipment repairs in the midlands. Nice guy, always helpful. Sorry to hear of his passing.
If it’s the same John I knew him too, I was an AV tech at Gear House in Birmigham and he would come in and service the broken equipment. I think his sons name was Ziggy.
Let's get this man some more subscribers. There are a lot of channels that are really crap that have more subscribers than he does. Mark is the real deal when it comes to repairing electronics! This man takes so much time and effort in putting these videos together. In such great detail, next to nothing skills and when something is not available, he makes it himself. Mark is such a nice guy, great knowledge and very entertaining to watch. Every time he puts out a new video like this, you can take your popcorn and drinks and watch this from start to end like you watch a new episode from your favorite series. Keep up the good work Mark, great to hear you move to a new workshop.
I couldn't agree more - unfortunately due to the stupidity of the vast majority of the human race most are drawn to the loud, flashy dumb stuff. This of course applies to all walks of life, not only TH-cam videos.
WOW ! 100 years ago I picked up a P2200 (same amp only with VU meters) in my last year of high school. I lugged that beast and a pair of Klipsch LaScallas around for years. All through college, got married moved into a brand new home they were with me every step of the way. Fantastic amp, never had a single problem. Makes me sad to see the condition of that old girl that you were working on but you brought her back to life good for another 50years. Great job, respect. I'm in Phoenix, Arizona and enjoy your accent and even temper. Thank You for posting.
@OldFatBubba many of these techie type people are kinda grouchy. Mark has got the best, most refreshing personality that Ive experienced. His channel should be in the millions of subs. Its money in the bank when he uploads a video. Hes the best by far. One of the main reasons I do TH-cam.
The sticky residue on the cables is from the smoke, not dry ice 😁 . The smoke fluid is water and glycol, and the glycol is the thing making the smoke white. If the smoke is used in a nightclub without any ventilation, the glycol will condense on stuff. A typical fault on movingheads is the condensed glycol on the cables inside, making the dust stick on them, and making them brittle.
Glycol is in "vape" smoke. Doubt there was much of that in the '70s and '80s. I think the sticky goo is phthalate plasticizer in the clear PVC tubing, which gradually sweats out to the surface (making the tubing itself gradually become more stiff.) That's why it's only the tubing that has sticky crud on it. It's an easy-to-replace item.
If it was gigged, it's probably real smoke.. I replaced the pickups in a Strat I used to use before smoking bans last month and it still stunk of cigarette smoke.
A great end to a hot and sunny weekend. I like the way Mark goes the extra mile to ensure that all repairs leave in a safe condition. Best of luck moving to your new workshop.
And a power amp is ready to re-enter service! Power amps are among the most useful pieces of vintage tech there is. Even a really good one from the '70s or '80s, once properly sorted, is really good even today.
Great job fixing this amp. These old Yamaha's perform extremely well and are of much higher build quality than what you'll find today. I actually have the model P2250, which is very similar to this one. Thanks for saving this one from the junk heap!
Toured in the 80's early 90's with racks of these running massive tour systems and monitors, I cannot remember one failing , rigged through a Trainor tour console, with a complete Shure Microphone's, FX from Peavy, nothing wireless at all, did not exist in my world. Best touring package I had in 25 years on the road. Thanks Yamaha, you made sure a lot of us tour techs looked good to our employers.
Mark, You've even made it to the Netherlands. I find your videos so informative and well-explained. It's just a positive therapy to watch you while doing the work you perform.
Thorough job Mark as always, you didn't cut any corners...fake parts are a real problem...came across it when trying to source some 2SC2922 and 2SC1905 Sanken devices....The real problem is not finding modern equivalent devices that can deliver the power, but can match the Early Voltage characteristics as well.
Not only are you extremely talented in electronics but you also understand how to make things from sheet metal and how to measure correctly. Absolutely awesome and I appreciate your TH-cam channel one of the best around.
I know sod all about electronics but I'll happily sit watching Mark carry out his repairs, a true craftsman at work! Love the intro music too! Look forward to seeing the new workshop. Thanks Mark!
I really like how absolutely every single thing that was done in this repair is left in the final edit. Really gives you a good idea of what's happening that a lot of other channels don't provide
I think when the former repairman found out that the blown transistors were out of production, he didn't bother to look for replacement, like Mark did.
@@drummerhammar It was very different 25 years ago. We don't appreciate how easy it is to source parts these days. I had to basically give up on quite a few things back then because parts simply were not available.
Mark's a gentleman leaving out displaying his underlaying knowledge and the judgement, though he sometimes subtle hints of what he thinks about other techs' solutions. In this case one cannot know the reason behind not finishing the repair by the previous tech, I know just to well that sometimes projects of gear you don't really use gets pushed behind.
I really admire the methodical way you work, your patience and your perfectionism. Your love of bringing back to life packages that no one else would repair. I don't think there are many like you. Even the videos are well taken. Thanks for what you do.
Genuine shock when Mark said he'll be moving shops, I thought he loved the clutter! Extremely organized, however the lack of space is only somewhat evident(;
Marvel at the professionalism and attention to detail in Marks repairs. I know absolutely nothing about electronics, but know Mark is an expert. Keep up the good work.
That is the sibling of the P-2200. That was a gorgeous amp with Awesome meters. Its downfall was, Yamaha made custom meter drive amp IC, an IG0.... something or other, that tended to fail and render the meters useless. It had a big Toroid transformer for mains. I never have seen a P-2201, but I can guarantee you that Yamaha would never leave their output transistors open on external heat sinks. This is a case where some lame servicer lost that stuff.
I can't believe I spent nearly an whole hour watching this, but I enjoyed it. Only tiny mention, I tend to preclean all soldier connections and avoid reusing any existing used solder, but not a big issue at all now is it 🤠 "73" from California
The abject anxiety I get watching Mark completely dismantle these old buggers is offset by the dopamine blast I get when it comes back together and actually works.
Hi Mark, I have this exact same amp and have had it from new when I bought it in the 80's. It still works brilliantly, it is built like a battleship! Thank you so much for uploading this video, I have learned so much from it.
For others watching - you have to be careful when substituting transistors in a power amplifier. It isn't always enough to make sure the replacements have the same or better specs on things like voltage and current - two important criteria Mark did not show here is Ft and Cob. You can have oscillation issues in some amplifier circuits if the outputs arent of similar speed or there is more/less Cob capacitance.
Yes, seemed all too simple a sub. Was there a step missing from the work - to match the amps output gain? After all, the driver and output transistors were substituted.
@@BTW... Negative feedback makes the transistor gain characteristic less important -- as it is somewhat close. Gain varies more than that difference from part-to-part.
@@BTW... No issue with gain as negative feedback deals with that, but stability can be an issue. I might have considered replacing the transistors in both sides just to make them a matched pair, though i doubt it is really neccesary.
what Mark might have done off camera, is tested with a square wave into a load, and looked at the scope. You'd see potential instability as severe over/undershoot on the waveform, with ringing. You'll always get some peaking but as long as it's not excessive and there is little to no ringing, you are OK. The original 2SC1586 transistors had an Ft of 10MHz and Cob of 110pF, where as the MJ15023 has an Ft of 4MHz and Cob of 600pF. Unfortunately there's no fast/low capacitance power transistors made in the TO-3 package any more. I also noted that the working channel had a failed Zobel network resistor. That's usually a sign that the amplifier has been oscillating. Maybe that's what took out the channel that had no parts in it.
This is my first time coming across your channel, and what a pleasure! Your repairs are so thorough, and your positive attitude is a joy. It's always satisfying to see old equipment being repaired instead of just thrown out. Excellent work.
I aquired a P2201 in 1986. Legendary. Indestructable. Great sound at home in the HiFi and kicked ass in school gymnasiums, weddings and hockey arenas. That and the P2200 are some of Yamaha's best work.
Having worked with that model in the early 1980s, I can't agree with your assessment at all. Yamaha makes some excellent drums, great brass instruments, very good motorcycles, and they make amps. Not great, not good, but adequate. Yamaha's amps have rather a lot of negative feedback which gives them decent harmonic distortion specifications, but they are an unpleasant source of phase distortion. Cheers, Alan Tomlinson
@@diegorhoenisch62 _Phase distortion?_ What? I mean, with the undegenerated BJT input stage it's not going to be a slew rate king, though relatively high gain ought to help with that, pulling off an amplifier this powerful with an EF2 seems like a bit of a stretch, and the output stage is a tad underbiased as they usually are... but it is a PA amp after all, they're not expected to be the last word in fidelity, and this one still easily qualifies as hi-fi. If you want a model that's beyond reproach by any standard, the ones to look for would be from their mid-80s lineup, like the P2250. Later ones went back to being a bit more on the rustic side, and by the mid-'90s even the noise level had begun to suffer.
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???
Outstanding work Mark, just outstanding. A master of many, many talents. I think I'll miss the current/old workshop, it has such a one man in a shed vibe, a bit of a cosy warm feel to it. However, I can't wait to see the new workshop, you might even have enough space to swing a cat and have a bit of elbow room.
yo sueño con tener un taller asi, y por supuesto, tu nivel de conocimiento para hacer tus trabajos... es impresionante, no conozco a nadie en Chile que llegue a ese nivel. Saludos Maestro!
That looked like a right basket case, but you sorted it all out very confidently and professionally. Love these videos and the "professional" gag at the start of this one. Would love for you to feature the cat more often!
Very impressive work you do not everyone can do...fantastic building of the Transistor shields...cool.. nice Equipment you have either...and a great knowledge in Electronics...
After watching the video again, I suddenly thought that you could have bought two sets of drivers and output transistors, with one set for the good channel. I've always been a fan of ON/Motorola transistors, particularly where reliability is concerned. I built my own class A amplifiers with MJ15003's in the output stage. The amps - monoblocks - have never missed a beat over many years of operation and sound superb.
Good Lord!?! What a toroidal transformer! Unlike any other transformer that I’ve ever discovered in any other piece of appliance. Nice. Balanced inputs. Your workshop is always pristine. You figure any engineer with an antique transformer curve tracer has had for himself a pretty long history of experiences in electronics. Mark, I don’t know where you got it from, but your English is the real treat of your channel! Wherever you’ve been, you really have a pleasant voice!
Great informative video Mark, thank you. One thing i would do differently than u for the power transistors is, i would split the mica insulation to the half thickness and premount them on the transistors with thermal grease applied on both sides, then only will mount the transistors on tje heatsink.
Greetings: A fine gem that is. U picked a great unit 4 the presentation. Yamaha, 70s and the problem were great combinations. I miss that era. Things were simple, durable, great quality and function by Ppl and companies that had pride. Now, not the case. All is crap. I serviced that model and many more in the day. Nearly a pleasure 2 service. U did a great job. Thx 4 the share.
So nice to see vintage lab equipment. I used to fix amplifiers and build tube amps and this gives me memories. Replacing power and driver transistors can be problematic sometimes with old amps but you made it look easy!
What a thrill to watch your vids. Someone also called Mark who still uses an analog 'scope and has a copy of Towers. Though I'm now retired (semi) I love watching someone else work; especially with the talk that accompanies it.
During the early 80's i used these amps in my touring PA system, It was a combination of P2200's which had meters on the front, P2201's like this which was the same but with no meters, And also some later P2200 which had 8 output devices per side and could also do a 2 ohm load. All in all i had 48 of these , they are loverly sounding amps.
Beautiful repair! Especially those folded metal covers are a nice touch, looks like brand new. I did cringe at the soldered leads into terminals though! Solder tends to exhibit quite a lot of creep, so a connection now can loosen up over a couple of years. Some people believe this to be the case, but I have seen it plenty of times myself, and even NASA says to avoid soldered wires in terminals (in their wiring guide). Nowadays I personally always go for the ferrule crimp tool, cheap as chips, solid, reliable, quick, easy and looks professional.
I don't get any of the technical stuff but somthing about Marks videos make it compeling viewing. Like many comments on here, I really look forward to the days these come out.
I have to commend Mark again, not just for the diag and repair work, but for the camera work and editing. He doesn't just record one camera angle, but usually gets a close-up of every single step. Like adjusting the pots, he often shows a shot of the pot itself, then a shot of the multimeter. In this video, he showed BOTH pots, the inrush current, a close-up of turning the power switch on and off, plugging in the jacks, adjusting the volume, showing the o'scope, showing the distortion meter, and even making new cover plates for the transistors. I can't imagine how long it takes to make one of these vids. lol Great channel.
Very encouraging video. I have a 1970s Sansui Ba-f1 power amp I have been struggling with for weeks after recapping it and causing shed loads of issues. But compared to this thing it looks brand new. I won't give up.
Thanks for sharing this thorough cleaning and repair. I love your attention to detail. I was surprised that you tinned the wires for the power cable. I was taught that any wire that goes into a screwed terminal must not be tinned/soldered. The solder will move under constant pressure over time and the connection can become loose. Better crimp a ferrule onto the wire.
Talk about going above and beyond!! I must admit to having very little clue about the technical stuff - but I look forward to every video! Thanks Mark.
every time i watch one of Mark's videos i end shaking my head and saying something like "how good is this guy at what He does" ...surely one of the very best of all time.
I am always blown away by your attention to detail Mark. And this Vid even more. Not only the electronics! Transistor covers gave an “Out of the Park” look of professionalism. Wow)
Just loved watching thisv-Takes me back to my Royal Navy Days doing component repairs to communication and Radar Systems. What a beautiful trip down memory lane.
I've still got my C64. It's still working after all these years. I think i should do a capacitor replacement for the old girl soon. My grandfather bought it for me back in 83. Love my grandfather. Oooo YT put the right comments on the wrong channel again. Still love your videos though Mark😊
Mark, you are reMARKable, makes me wanna take up electronics full time, but ive really been annoyed by some circuits ive come across lately...anyway sir really enjoyed your video, watched it all, i have really learned from you....never saw you on youtube before now, but you have a new fan....give thanks for knowledge,and thank you for sharing....dont know why you dont have a million views,,,,but keep up your good work sir. blessings.
Mark questa volta vedere questo video è stato assolutamente fantastico. Le cover Autocostruite sono di una spettacolarità assurda. Hai talmente tantissima competenza in ciò che fai ché di una professionalità inarrivabile da poche persone. Con una maestria e una tranquillità in ciò che ripari, mette di un buon umore chi guarda i tuoi video. Io da tecnico elettronico posso soltanto inchinarmi a cotanta tecnica ed imparare ancora di più da te. Ti mando un'abbraccio dall'Italia caro Mark. Sei il numero uno veramente.
This is the most impressive one I've seen from you so far. It is really inspiring to see all the steps, including the making of custom parts. Makes me also dream of having a bigger shop and some more testing equipment and specialized tools. Looking forward for your Time Travel live workshop
They're beautiful brutes of amplifiers. Many years ago I repaired one of these that had suffered a "thermal event" that blew up one of the sides. It has a very nice safe operating area limit circuit that limits the output current near zero volts. This will prevent the amplifier overheating during normal operation with a blower passing considerable air over the cooling fins. The amplifier in question was being used in a practice room and the fans were turned off since they were noisy. This would have been OK, as the power out was probably around 10 watts instead of its usual flat-out front of house duty. The speaker wire was a bit dodgy and shorted out. The safe operating area circuit would have prevented any damage, had the blowers been running but... The thermal switch on the heat sink only lights up the over-temp indicator and doesn't shut the amplifier down. The output stage and the output drivers were all blown up. After the repair, I installed thermal switch buttons on the heat sinks to prevent this recurring.
Another cracking video, no covers just make them, you are so skilled and proven that most.things can be repaired rather than dumped. Please do a tour of your new workshop when it's done keep up the great work
UPDATE:
So I’m running a 3-part LIVE workshop that takes us on…
A Time Travel Through Vintage Electronics.
We’ll rewind the clock, dive into the tech of the times…
(and study the very history of how things were broken and repaired has evolved)
The workshop is coming soon, but if you're reading this then you're in luck (or not)...
And there's still time for you to sign up using the link below:
www.menditmark.com/mend-mark-workshop
The workshop dates are mentioned in the link above too.
I signed up immediately! I didn't understand a word because I don't speak English but I'm sure it will be great!
? M)) p)ft
I signed up, can't wait. Greetings from Milan, Italy.
Is it going to be on youtube, or is this going to be somewhere else like Twitch or something?
of course, for me in German 'VE99' and 'curious marc' is nr 1, than 'mr carlsons lab'..
Is there anything that you don't look forward to more than a new Mark video? Keep them coming please!! Also, it would be great to hear how you gained your knowledge. Electronics, chemical, mechanical, you know it all!
Absolutely - go straight there when there is a new one!
Totally agree!
I'm so happy when a new video is uploaded!
I agree!
I don't know if anyone else notices the superb editing & audio on Mark's videos? Just the little touches like changing the sine audio level as it's varied on the amp, sublime.
Fabricating those transistor covers is just next-level refurb; not only painting, but matching the text. Awesome.
Mark has the skills and tools for every problem. He even has a labeling machine for this very purpose that cuts out the warning labels per spec.
I would have used TO-3 plastic covers!
I recognise that amp as one from Birmingham Repotory theatre. It came into where I was working at hte time for service. The initials JD belonged to John Deakin one of the service technicians.
A long time ago in the seventies. He has since passed away sadly.
I knew John quite well. He did most of the large heavy audio equipment repairs in the midlands. Nice guy, always helpful. Sorry to hear of his passing.
"A long time ago in the seventies. He has since passed away sadly." But his amp lives on, we should call it 'John's amp' serviced by Mark
Wow, that's bizarre.
If it’s the same John I knew him too, I was an AV tech at Gear House in Birmigham and he would come in and service the broken equipment. I think his sons name was Ziggy.
@@robnickels7267 It is indeed sir, and I remember you being there also under the supervision of the "Fat Controller". Mr Mandeville.
Let's get this man some more subscribers.
There are a lot of channels that are really crap that have more subscribers than he does.
Mark is the real deal when it comes to repairing electronics!
This man takes so much time and effort in putting these videos together.
In such great detail, next to nothing skills and when something is not available, he makes it himself.
Mark is such a nice guy, great knowledge and very entertaining to watch.
Every time he puts out a new video like this, you can take your popcorn and drinks and watch this from start to end like you watch a new episode from your favorite series.
Keep up the good work Mark, great to hear you move to a new workshop.
Totally agree. I’m sure he’s a guy you could have a drink and share a laugh with too.
Yep, I can think of one with double the subs and I don't get it !
Spot on! Let's get him more subscribers
Like watching a whodone it on telly
I couldn't agree more - unfortunately due to the stupidity of the vast majority of the human race most are drawn to the loud, flashy dumb stuff. This of course applies to all walks of life, not only TH-cam videos.
Dare I say that Mark's videos are on the edge of being therapeutic to watch! Thanks so much, Mark!
He is such a positive guy!
Absolutely! I 100% agree!
He's in my top 3 list here on YT for sure. He should have a million subs and his channel will grow and grow if he stays with it.
it's approaching an addiction for me. I love this guy. Every aspect of his uploads are excellent.
Agreed - I'm working my way through all the past episodes.
WOW ! 100 years ago I picked up a P2200 (same amp only with VU meters) in my last year of high school. I lugged that beast and a pair of Klipsch LaScallas around for years. All through college, got married moved into a brand new home they were with me every step of the way. Fantastic amp, never had a single problem. Makes me sad to see the condition of that old girl that you were working on but you brought her back to life good for another 50years. Great job, respect. I'm in Phoenix, Arizona and enjoy your accent and even temper. Thank You for posting.
Mark exudes confidence and competence. You know he’ll sort this disaster
Mark is one of my favorite net personalities. Straightforward with no mucking about. Can't wait to see the new digs.
@OldFatBubba many of these techie type people are kinda grouchy. Mark has got the best, most refreshing personality that Ive experienced. His channel should be in the millions of subs. Its money in the bank when he uploads a video. Hes the best by far. One of the main reasons I do TH-cam.
Mark shows us a level of craftsmanship that many ‘repair shops’ don't even know exists.
The sticky residue on the cables is from the smoke, not dry ice 😁 . The smoke fluid is water and glycol, and the glycol is the thing making the smoke white. If the smoke is used in a nightclub without any ventilation, the glycol will condense on stuff. A typical fault on movingheads is the condensed glycol on the cables inside, making the dust stick on them, and making them brittle.
Imagine what it does to ya lungs.
@@BTW... and yet some people are now carrying around pocket sized smoke machines to suck on them at any free moment they have
Glycol is in "vape" smoke. Doubt there was much of that in the '70s and '80s. I think the sticky goo is phthalate plasticizer in the clear PVC tubing, which gradually sweats out to the surface (making the tubing itself gradually become more stiff.) That's why it's only the tubing that has sticky crud on it. It's an easy-to-replace item.
If it was gigged, it's probably real smoke.. I replaced the pickups in a Strat I used to use before smoking bans last month and it still stunk of cigarette smoke.
@@BTW... it's also used in inhalers
A great end to a hot and sunny weekend.
I like the way Mark goes the extra mile to ensure that all repairs leave in a safe condition.
Best of luck moving to your new workshop.
You won’t find anyone as professional as Mark he’s the best !
This is more than just mending. To see someone taking care to recreate missing parts from raw steel is truly a labor of love.
And a power amp is ready to re-enter service! Power amps are among the most useful pieces of vintage tech there is. Even a really good one from the '70s or '80s, once properly sorted, is really good even today.
No surface mount items, no chips...ah the joy of components that can be examined, tested and replaced without magnification!
Built when amps were designed to be fixed before tomorrows gig.
@@alfsmith4936 Nooo, these are built to be fixed during the gig ;)
Great job fixing this amp. These old Yamaha's perform extremely well and are of much higher build quality than what you'll find today. I actually have the model P2250, which is very similar to this one. Thanks for saving this one from the junk heap!
Toured in the 80's early 90's with racks of these running massive tour systems and monitors, I cannot remember one failing , rigged through a Trainor tour console, with a complete Shure Microphone's, FX from Peavy, nothing wireless at all, did not exist in my world. Best touring package I had in 25 years on the road. Thanks Yamaha, you made sure a lot of us tour techs looked good to our employers.
Mark,
You've even made it to the Netherlands. I find your videos so informative and well-explained. It's just a positive therapy to watch you while doing the work you perform.
Mark, your attention to detail and general knowledge and professionalism never ceases to amaze. Good luck in your new workplace
It's better to watch you working than to watch a Hollywood action movie. Lots of love and regards from Pakistan. Stay blessed.
Thorough job Mark as always, you didn't cut any corners...fake parts are a real problem...came across it when trying to source some 2SC2922 and 2SC1905 Sanken devices....The real problem is not finding modern equivalent devices that can deliver the power, but can match the Early Voltage characteristics as well.
Not only are you extremely talented in electronics but you also understand how to make things from sheet metal and how to measure correctly. Absolutely awesome and I appreciate your TH-cam channel one of the best around.
I'm American and I love your accent. You are my current favorite TH-camr. Awesome job, I was mesmerized.
I know sod all about electronics but I'll happily sit watching Mark carry out his repairs, a true craftsman at work! Love the intro music too! Look forward to seeing the new workshop. Thanks Mark!
I really like how absolutely every single thing that was done in this repair is left in the final edit. Really gives you a good idea of what's happening that a lot of other channels don't provide
Meaning to say this for a while. Whoever designed the sound for your videos is a genious. The precision, but also calm inducing.
Your cheerful confidence seems born of experience and a good attitude. Most of us would be scared to tackle the projects you take on in stride.
Mark, you make these repairs look so easy! The missing parts is simply amateur workmanship and unforgivable.
I think when the former repairman found out that the blown transistors were out of production, he didn't bother to look for replacement, like Mark did.
@@drummerhammar It was very different 25 years ago. We don't appreciate how easy it is to source parts these days. I had to basically give up on quite a few things back then because parts simply were not available.
Mark's a gentleman leaving out displaying his underlaying knowledge and the judgement, though he sometimes subtle hints of what he thinks about other techs' solutions. In this case one cannot know the reason behind not finishing the repair by the previous tech, I know just to well that sometimes projects of gear you don't really use gets pushed behind.
Also possible that the amp was cannibalized for parts (those rare transistors in particular).
Back in the day, If it works for tonight's gig, it works until it needs fixing again.
I really admire the methodical way you work, your patience and your perfectionism. Your love of bringing back to life packages that no one else would repair. I don't think there are many like you. Even the videos are well taken. Thanks for what you do.
Genuine shock when Mark said he'll be moving shops, I thought he loved the clutter!
Extremely organized, however the lack of space is only somewhat evident(;
Marvel at the professionalism and attention to detail in Marks repairs. I know absolutely nothing about electronics, but know Mark is an expert. Keep up the good work.
Good afternoon Mark! I can relax, cuppa tea, and watch your great video!
That is the sibling of the P-2200. That was a gorgeous amp with Awesome meters. Its downfall was, Yamaha made custom meter drive amp IC, an IG0.... something or other, that tended to fail and render the meters useless. It had a big Toroid transformer for mains. I never have seen a P-2201, but I can guarantee you that Yamaha would never leave their output transistors open on external heat sinks. This is a case where some lame servicer lost that stuff.
I’ve watched the Yamaha repair again for the third time. So enjoyable to watch. Like rereading a good book and you still pick up new things from Mark!
Those transistor covers were such a clever idea. The printer trick was clever as well.
Absolutely amazing repair! You can't admire more that these amps never get old!
Thanks Mark
Cover fabrication at the end was just amazing. Really rooting for this channel to grow big.
I can't believe I spent nearly an whole hour watching this, but I enjoyed it. Only tiny mention, I tend to preclean all soldier connections and avoid reusing any existing used solder, but not a big issue at all now is it 🤠
"73" from California
The abject anxiety I get watching Mark completely dismantle these old buggers is offset by the dopamine blast I get when it comes back together and actually works.
I know exactly what you mean
I mostly have no idea what you are talking about but your style is very engaging so I keep watching
New workshop coming !!! Interesting Mark.
I prefer to keep things as they are. It is difficult enough to keep track of where I put stuff 😄
Hi Mark, I have this exact same amp and have had it from new when I bought it in the 80's. It still works brilliantly, it is built like a battleship! Thank you so much for uploading this video, I have learned so much from it.
I bet if you sent Mark a shoebox and told him it was a McIntosh amp, you’d get a McIntosh amp back in 10 business days 😂
😂😂😂
I'll be sending him my Dumble next week then.. I don't know why it's not working. It's very light too..
LOL!!!!
I can just hear him say, " some parts were missing so I had to improvise with a bit of wood and metal work here in the workshop." LOL!
7 days on a Sunday 💯😂
For others watching - you have to be careful when substituting transistors in a power amplifier. It isn't always enough to make sure the replacements have the same or better specs on things like voltage and current - two important criteria Mark did not show here is Ft and Cob. You can have oscillation issues in some amplifier circuits if the outputs arent of similar speed or there is more/less Cob capacitance.
Yes, seemed all too simple a sub. Was there a step missing from the work - to match the amps output gain? After all, the driver and output transistors were substituted.
@@BTW... Negative feedback makes the transistor gain characteristic less important -- as it is somewhat close.
Gain varies more than that difference from part-to-part.
@@BTW... No issue with gain as negative feedback deals with that, but stability can be an issue.
I might have considered replacing the transistors in both sides just to make them a matched pair, though i doubt it is really neccesary.
what Mark might have done off camera, is tested with a square wave into a load, and looked at the scope. You'd see potential instability as severe over/undershoot on the waveform, with ringing. You'll always get some peaking but as long as it's not excessive and there is little to no ringing, you are OK.
The original 2SC1586 transistors had an Ft of 10MHz and Cob of 110pF, where as the MJ15023 has an Ft of 4MHz and Cob of 600pF. Unfortunately there's no fast/low capacitance power transistors made in the TO-3 package any more.
I also noted that the working channel had a failed Zobel network resistor. That's usually a sign that the amplifier has been oscillating. Maybe that's what took out the channel that had no parts in it.
A sunday with Mark! Splendid
This channel is criminally under appreciated, when you reworked that motor a few videos ago that hooked me in.
This is my first time coming across your channel, and what a pleasure! Your repairs are so thorough, and your positive attitude is a joy. It's always satisfying to see old equipment being repaired instead of just thrown out. Excellent work.
Can we all admire what appears to be masking tape with “nope!” written on it :D
"Nope!" ... We can't!
I do that at the Cooker before the wife begins
I aquired a P2201 in 1986. Legendary. Indestructable. Great sound at home in the HiFi and kicked ass in school gymnasiums, weddings and hockey arenas. That and the P2200 are some of Yamaha's best work.
Having worked with that model in the early 1980s, I can't agree with your assessment at all. Yamaha makes some excellent drums, great brass instruments, very good motorcycles, and they make amps. Not great, not good, but adequate. Yamaha's amps have rather a lot of negative feedback which gives them decent harmonic distortion specifications, but they are an unpleasant source of phase distortion.
Cheers,
Alan Tomlinson
@@diegorhoenisch62 _Phase distortion?_ What?
I mean, with the undegenerated BJT input stage it's not going to be a slew rate king, though relatively high gain ought to help with that, pulling off an amplifier this powerful with an EF2 seems like a bit of a stretch, and the output stage is a tad underbiased as they usually are... but it is a PA amp after all, they're not expected to be the last word in fidelity, and this one still easily qualifies as hi-fi.
If you want a model that's beyond reproach by any standard, the ones to look for would be from their mid-80s lineup, like the P2250. Later ones went back to being a bit more on the rustic side, and by the mid-'90s even the noise level had begun to suffer.
i watch his videos only for pleasure..this guy seems very humble and nice...
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???
Outstanding work Mark, just outstanding. A master of many, many talents.
I think I'll miss the current/old workshop, it has such a one man in a shed vibe, a bit of a cosy warm feel to it. However, I can't wait to see the new workshop, you might even have enough space to swing a cat and have a bit of elbow room.
yo sueño con tener un taller asi, y por supuesto, tu nivel de conocimiento para hacer tus trabajos... es impresionante, no conozco a nadie en Chile que llegue a ese nivel. Saludos Maestro!
He’s so clever. It seems like there is always something new to learn in each video.
I don't know much about electronics, but it's always like a thriller to watch you; your skills are fascinating.
Looking forward to seeing the new workshop.👍🇩🇰
That looked like a right basket case, but you sorted it all out very confidently and professionally. Love these videos and the "professional" gag at the start of this one. Would love for you to feature the cat more often!
I'm kind of sad that you're moving to another shop yours has such honest character
This is some serious workmanship. Mark you are amazing.
He’s Mend it Mark AND Bend it Mark…!!! those covers are awesome! 👏 🔥
Mend it, Bend it and Print it Mark!
Very impressive work you do not everyone can do...fantastic building of the Transistor shields...cool..
nice Equipment you have either...and a great knowledge in Electronics...
I am a hard man to impress but you impress me very much Mark
I'm sure that Mark is not that wayl inclined
After watching the video again, I suddenly thought that you could have bought two sets of drivers and output transistors, with one set for the good channel. I've always been a fan of ON/Motorola transistors, particularly where reliability is concerned. I built my own class A amplifiers with MJ15003's in the output stage. The amps - monoblocks - have never missed a beat over many years of operation and sound superb.
Excited to see the new workshop!🙂
Good Lord!?! What a toroidal transformer! Unlike any other transformer that I’ve ever discovered in any other piece of appliance.
Nice. Balanced inputs. Your workshop is always pristine. You figure any engineer with an antique transformer curve tracer has had for himself a pretty long history of experiences in electronics. Mark, I don’t know where you got it from, but your English is the real treat of your channel! Wherever you’ve been, you really have a pleasant voice!
Thanks Mark. Real entertainment on a sunny Sunday afternoon in North west Germany
Superb video - it certainly brought back memories of casting envious eyes over Yamaha amps back in the 1970s, which seemed very classy at the time.
I'll miss the old workshop for sure, Mark. Quaint. Calm. Homey.
Great informative video Mark, thank you. One thing i would do differently than u for the power transistors is, i would split the mica insulation to the half thickness and premount them on the transistors with thermal grease applied on both sides, then only will mount the transistors on tje heatsink.
It feels like Christmas! Mark has turned up!
Greetings: A fine gem that is. U picked a great unit 4 the presentation. Yamaha, 70s and the problem were great combinations. I miss that era. Things were simple, durable, great quality and function by Ppl and companies that had pride. Now, not the case. All is crap. I serviced that model and many more in the day. Nearly a pleasure 2 service. U did a great job. Thx 4 the share.
New workshop?.......looking forward to it!
I didn’t have a clue what you were doing from beginning to end. But I still watched in fascination.
Sunday is complete… cold beer sitting in the garden with Mark… 🎉😂
The making of the heat sink rail covers was great alone.
Excellent video and skills in a fun presentation.
Bien, otro maravilloso video 👍
It is remarkable how he remembers to reassemble everything how it was. I use don’t know how he does it. What a genius he is and funny also.!
MARKKKK!!!! 😊
Mark sei il più bravo, competente, professionale riparatore elettronico al mondo. I tuoi video mi incantano.
So nice to see vintage lab equipment. I used to fix amplifiers and build tube amps and this gives me memories. Replacing power and driver transistors can be problematic sometimes with old amps but you made it look easy!
What a thrill to watch your vids. Someone also called Mark who still uses an analog 'scope and has a copy of Towers.
Though I'm now retired (semi) I love watching someone else work; especially with the talk that accompanies it.
During the early 80's i used these amps in my touring PA system, It was a combination of P2200's which had meters on the front, P2201's like this which was the same but with no meters, And also some later P2200 which had 8 output devices per side and could also do a 2 ohm load. All in all i had 48 of these , they are loverly sounding amps.
Beautiful repair! Especially those folded metal covers are a nice touch, looks like brand new.
I did cringe at the soldered leads into terminals though! Solder tends to exhibit quite a lot of creep, so a connection now can loosen up over a couple of years. Some people believe this to be the case, but I have seen it plenty of times myself, and even NASA says to avoid soldered wires in terminals (in their wiring guide).
Nowadays I personally always go for the ferrule crimp tool, cheap as chips, solid, reliable, quick, easy and looks professional.
I don't get any of the technical stuff but somthing about Marks videos make it compeling viewing. Like many comments on here, I really look forward to the days these come out.
I have to commend Mark again, not just for the diag and repair work, but for the camera work and editing.
He doesn't just record one camera angle, but usually gets a close-up of every single step.
Like adjusting the pots, he often shows a shot of the pot itself, then a shot of the multimeter.
In this video, he showed BOTH pots, the inrush current, a close-up of turning the power switch on and off, plugging in the jacks, adjusting the volume, showing the o'scope, showing the distortion meter, and even making new cover plates for the transistors.
I can't imagine how long it takes to make one of these vids. lol
Great channel.
indeed. The viewer almost has a better view than the engineer!
Very encouraging video. I have a 1970s Sansui Ba-f1 power amp I have been struggling with for weeks after recapping it and causing shed loads of issues. But compared to this thing it looks brand new. I won't give up.
Thanks for sharing this thorough cleaning and repair. I love your attention to detail.
I was surprised that you tinned the wires for the power cable. I was taught that any wire that goes into a screwed terminal must not be tinned/soldered. The solder will move under constant pressure over time and the connection can become loose. Better crimp a ferrule onto the wire.
Talk about going above and beyond!! I must admit to having very little clue about the technical stuff - but I look forward to every video! Thanks Mark.
every time i watch one of Mark's videos i end shaking my head and saying something like "how good is this guy at what He does" ...surely one of the very best of all time.
I am always blown away by your attention to detail Mark.
And this Vid even more.
Not only the electronics!
Transistor covers gave an “Out of the Park” look of professionalism.
Wow)
Just loved watching thisv-Takes me back to my Royal Navy Days doing component repairs to communication and Radar Systems. What a beautiful trip down memory lane.
I've still got my C64. It's still working after all these years. I think i should do a capacitor replacement for the old girl soon. My grandfather bought it for me back in 83. Love my grandfather. Oooo YT put the right comments on the wrong channel again. Still love your videos though Mark😊
Mark, you are reMARKable, makes me wanna take up electronics full time, but ive really been annoyed by some circuits ive come across lately...anyway sir really enjoyed your video, watched it all, i have really learned from you....never saw you on youtube before now, but you have a new fan....give thanks for knowledge,and thank you for sharing....dont know why you dont have a million views,,,,but keep up your good work sir. blessings.
Mark questa volta vedere questo video è stato assolutamente fantastico.
Le cover Autocostruite sono di una spettacolarità assurda.
Hai talmente tantissima competenza in ciò che fai ché di una professionalità inarrivabile da poche persone.
Con una maestria e una tranquillità in ciò che ripari, mette di un buon umore chi guarda i tuoi video.
Io da tecnico elettronico posso soltanto inchinarmi a cotanta tecnica ed imparare ancora di più da te.
Ti mando un'abbraccio dall'Italia caro Mark.
Sei il numero uno veramente.
Wydaje się użycie niewłaściwego wkrętaka. Gniazda wkrętów jak widać są typu philips, a wkrętak pozidriv. Super blog.
Mark, you go after these complete basket cases! Once I saw all those transistors missing, I was yelling TRASH IT! You are amazing!
I'm an EET student and I share your videos with my fellow students. You are the reason I got into working on legacy equipment!
This is the most impressive one I've seen from you so far. It is really inspiring to see all the steps, including the making of custom parts. Makes me also dream of having a bigger shop and some more testing equipment and specialized tools. Looking forward for your Time Travel live workshop
They're beautiful brutes of amplifiers.
Many years ago I repaired one of these that had suffered a "thermal event" that blew up one of the sides.
It has a very nice safe operating area limit circuit that limits the output current near zero volts. This will prevent the amplifier overheating during normal operation with a blower passing considerable air over the cooling fins.
The amplifier in question was being used in a practice room and the fans were turned off since they were noisy. This would have been OK, as the power out was probably around 10 watts instead of its usual flat-out front of house duty. The speaker wire was a bit dodgy and shorted out. The safe operating area circuit would have prevented any damage, had the blowers been running but...
The thermal switch on the heat sink only lights up the over-temp indicator and doesn't shut the amplifier down.
The output stage and the output drivers were all blown up. After the repair, I installed thermal switch buttons on the heat sinks to prevent this recurring.
Another cracking video, no covers just make them, you are so skilled and proven that most.things can be repaired rather than dumped.
Please do a tour of your new workshop when it's done keep up the great work