27:02 I always train my people to cut first. one part of the reason is just as you pointed out. the other reason is that there is the chance to lift up the pad (single sided mostly) by the physical impulse that is presented by the cutting action "snap". Also you provide less thermal inertia by cutting the leads off, so you can solder the components more quickly and do less thermal stress. *thumbs up*
Hi Tony, I've learned that you shall cut the leads before you solder, because the risk of weakening (cracking) the solder joint. I think it was mentioned that solder can break at only 10 grams. Your arguing capacitors reminded me of "D-Lab Electronics" (UA-cam) that sometimes also make sketches as intros.
Hi Tony just started watching the video and when you got to the part about cataracts and laser or lasik surgery I thought I would jump in with my 2cents. I’m getting ready for my cataract surgery and in the preliminary eye exam there were questions regarding having any of the lasik or laser and how that would have a concern. Now I’m going with a mult-focal lense called Vivity it’s the latest lense on the market. Due to COVID-19 my health care provider is backed up for several months but I expect to have it done this summer. You may want to research this before making the final decision. Now I’ll be 66 then and will never need to replace them. Good luck and back to video for me
Interesting that the power transistors use a common heatsink with separate sensor diodes for each channel. So if you were only driving one channel the QI on the other would also change the bias. In practice however, being a stereo amplifier both channels would see much the same average power output.
I had to think about this for a while, but I can see how this would work. All of the output transistors share a common heatsink. As such, they will all be at a common temperature. If the temperature of one channel increases, it will raise the temperature of the transistors of the other channel, which will affect the Vbe on them as well. The bias diodes are also common to the heatsink (temperature-wise), so they will change as well, which will keep the bias in order. This is a pretty common design on all of the mid-power amplifiers of this era. The higher-powered amplifiers will have a separate heatsink for each channel. Thanks for the comment!
I was working on a SR7000g which also has the stabistors one lead broke off flush . took a dremmel tool with tiny diamond bit and ground away the epoxy around the lead enough to solder and re epoxy . Totally worth the trouble sounds great
regarding eye implants; I was using multifocal glasses for about 25 years, after researching a year, I went for Johnson&Johnson's top of the line implants (5 months ago). My eyes were over 4 in dioptry + astigmatism. Doc said he prefers not to go for correcting astigmatism and I opted. Results; I need good lightning to read and do precision work. 4000+ K lights are my friends now (i hate white light normally). Other than that you will see halos (rings) around bright lights (especially LEDs), so driving at night is a little funny, stop lights and headlights disturbs a little, you feel like you are in Vegas :) Because of those rings (or halos), contrast isn't that great (that's why you need good light). So 20/20 is not possible. But doc said it's about the brain, it will choose not to see those rings with time (they will be there but brain will ignore them) Other than these, it's ok to go for it. I have replaced all of my eye glasses with sun glasses (8+) ;) So make your choice with these in mind, do not take ads and doctor's sayings.
Hey Tony, there is a guy in Germany that has the STV-3HY stabistor diodes. I have used them myself in a few Sansui receivers and they work just fine. Littlediode in the U.K. sells them too, but at a little higher price.
Having had cataract surgery several years ago, I can tell you not to wait. In time you may develop secondary cataracts, which are taken care of by a laser. I had that done on my left eye a couple of years ago. My right eye doesn't need the laser treatment yet. Insurance doesn't pay for Lasik, but it does pay for cataract surgery.
I now have visions of you in a orange colored suit of armor straddling a capacitor/horse via Monty Python style skit. Thoose old BBC shows are still on PBS generally on Saturday night.
Tony interesting you showing the internals of the power transistor and compared it to those that are high quality ones. Those made in Japan are of very high quality. I am at the age where I remember when we in the US was complaining that Japan did not make good quality components. Well, it's a rarity to find stuff that says made in japan, let alone made in the USA. I have my doubts China would reach to the level of the same quality of what was made.
Another little "tip" for the transistors on the heat sinks. Unscrew the transistors (when feasible), then unscrew the heat sinks. Remove the heat sink without desoldering the transistors. That is as long as you know the transistors are good. If you need to replace the transistor, without the heat sink allows you to "wiggle" the transistor while desoldering with the Hakko making it easier to remove when the leads are folded over so bad. Wiggling the transistor towards the "fold" will lift it enough the Hakko can suck the solder up.
Tony, Monty Python +, I find this very interesting because I have a Pioneer SX737 that needs to be brought back to life. I am learning a lot of tips on what to do and what not to do. I'm very interested in your oscilloscope setup. I have tried to setup using a modern Chinese 50W audio amp driving across an 8 ohm wire wound ceramic resistor. The resistor is rated at 100W. I would appreciate it if you would give details about your setup in the next video. My setup is picking up a lot of noise. My experience in electronics dates back to my high school days back in the 60s. I dropped it as a hobby when I started in aviation for the next 48 years. Now that I'm retired I've picked it back up and having a lot of fun. Keep up your great video work, you are the best!
27:30 I don't think that copper being exposed is any issue. Corrosion on copper has the special characteristic that it builds a protective coating on the surface of the copper that stops any further corrosion. It's not like rust on iron that just eats away on the metal until it's all rusted away. That's why they used sheets of pure copper on the roofs of churches in the old days. It would corrode and turn green in the beginning, but then would stop corroding and then last almost forever without the need for any maintenance.
When I build gear, and I build a lot of recording equipment, I don't like to bend the leads over on the solder side for most common components. I don't like to do it so it's easier to desolder, should I, or another tech have to do it in the future.
Whoa! Lots to comment on in this video! Who doesn't love all the Monty Python stuff? The Life Of Brian is still one of my favourite! I was showing my kids the bigges dickes scene just a few days ago LoL. Your voice acting was spot on! I definitely had a good laugh 😂. Eye surgery might appear to be way off topic but try doing this sort of work with your eyes closed! I think that it's part and parcel of this profession! I had really good eyes till I was just over 40 something and then my ability to focus on things near and far went up the proverbial creek without a paddle! I need two different pairs of glasses now, one to see things up close and the other to see everything else, the only time I I don't need glasses to see is when I'm asleep and having a dream, strangely though, it appears that the dream that I'm seeing is actually being seen with my eye's, almost like the eye's are both the receiver and the processor of vision! In when the image gets processed and shipped out into memory and then later recalled to the eye's, reprocessed, CGI added and then resent into storage! Yeah! Dreams are really strange! And finally, that potentiometer, you mentioned a loudness tap? I know that I have given who a loudness circuit would be controlled but that was a very long time ago and haven't really thought about it since. Does that potentiometer have three pot's inside it or something? This isn't something that is discussed much, more like there's nothing on UA-cam on this topic alone! Another circuit that has always fascinated me is the stereo wide circuit that was fitted to many boomboxes throughout the 70's and 80's, I have tried to search for that type of circuit but I haven't really found one. My boombox used a switch and gave a choice of mono/stereo/stereo wide, but there were some that had a potentiometer where you could continually adjust to what sounded best but as I said earlier, I have yet to find such a circuit diagram anywhere... Capacitors capacitors capacitors! It's a never ending topic! I watched a recent video on a subwoofer amplifier repair, I watched as the person went through checking capacitors in circuit with his Bob Parker ESR meter and claiming that they are all excellent even though he himself mentioned that a few of them were expanded! He's a great guy and works on a lot of interesting things but I often find myself screaming at the screen out of frustration! Why have a lot of people fallen into the ESR trap? There's just no easy way around it! The only thing that an in circuit ESR tester is actually good for is checking capacitors in the power supply where ESR is a critical factor and the other is seeing if a capacitor in circuit is failed open or short! Leakage or EPR or Vloss or disapation or whatever you want to call it can only be measured out of circuit! There's no free lunch! They have to come out to be checked otherwise you have no idea of their actual condition! And when it comes to replacing capacitors, I have a golden rule! If I value the equipment that I'm working on, it takes longer but I always check to see if I can get a higher voltage rated capacitor at the same capacity to fit in the same location, especially if it is located next or near a heat source!!! This golden rule will ensure that the equipment will live a lot longer than what it already has! When it comes to old capacitors like the paper in wax, I saw a video in where RCA Victor was testing those things at twice their rated voltage! Think about that for a minute! It's rating printed on it's side is probably 400V but they are putting 800V across it, try that with today's capacitors!!! I dare you! And if anyone has been following Mr Carlson's Lab, would have seen him test capacitors on old Heathkit and various other old test equipment, and you would have seen that even a bad capacitor only start's showing it's point of failure at the top end of it's voltage rating! This I believe is the same failure mode of modern capacitors also! They always fail from top down! So then! If you go up in voltage on the replacement capacitor, it's going to last a lot longer than the original one! And going up in voltage also means it's going to be physically larger and provide both better thermal insulation and disapation at the same time, an 85°C rated capacitor at 350V will be like 105°C rated capacitor when used in a 50V circuit (the voltages are just a hypothetical situation) but I'm sure that you get my point, if you have a look at the Panasonic capacitor datasheet, you can see that this effect is true and correct. I just want to see all ESR meters banished, to many people are using them incorrectly and teaching everyone else this bad practice! This is giving the industry a bad name! The customer has watched someone go over the equipment with an ESR meter on a many videos and now wants to know why you took so long? Do you want it repaired or do you feel like bringing it back in a month's time to spend some more money on it? Yeah I'm ranting but capacitors are a touchy topic for me! I'm just trying to get the awareness out there that there's a better way to do it, going by this golden rule, you can get away with using no name brand capacitors and still get great long life performance at a cheaper price for the budget conscious customer! You don't want to be working on the same equipment that you have already worked on! You want the customer to bring new challenges and know that they trust you to do the right thing! Now! That's all done ✅ Transistors!!! Have you ever tried to connect that TO3 that you have opened up it's case and connected it to the scope and see what happens when you shine a light on it's die? It's supposed to behave like a tiny solar panel, I wonder what sort of power it could put out? Same thing happens when you shine a light on an led! Although it's not very efficient at producing as it is emitting! It's a great experiment that a lot of people don't know that transistors and LEDs are able to do this, kinda like a speaker which can also be a microphone! Technically an optocoupler is the transistor that is being controlled by light!
I think the Elna caps your referring to Tony is the Silmic II types. Great for audio and my first choice over the Nichicon gold types but larger values can be too big for certain applications, which is the only draw back.
In Sweden when i was young i learned that you always cut the leads when you repair/ manufacture military equipment. Since i heard that (30 yrs ago) i've done it everyday and i've seen some amps i've repaired/ restored have had issues with corrosion when leads been cut after soldering so yes you're doing the right thing. Another thing; Try out Elna Silmic II, available from mouser and digikey. I've done sound comparions and i rank the caps in this order; 1. Elna Silmic II . Warm sounding with good detail, almost like a filmcap. Elna Cerafine; Very clear and detailed but can be too clear. Can do wonders sometimes. Cerafine hard to get. 2. Nichicon KZ "Muse" I call this the Rock n' roll cap. Big and bould sound. 3. ES " Muse" (green ones) Bipolar. 4. Fine gold (Neutral but a bit boring) Above ones are most better for signalpath. 5. FW - Yamaha uses tones of these and Fine gold in their new premium amps btw.. 6. KA (blue sleeve as KT) 7. KT (KT is actually worse/older version of KA) -Use KA when you can. -Nippon has a audiocap that being used by Sony, Yamaha and others, Nippon ASG. -Never use Nichicon VR/VZ in signalpath. Horrible dark sound and no bass. Arcotronics/ Kemet R-series are ofcourse better when they fit. Actually prefer them instead of Wima MKS. But the best is nos ROE (Roederstein) for example MKT 1813/1818/1822/1826. You're a fun dude. Good videos. Learned a lot. Many thx!
You are absolutely delusional with those remarks that you can remember how a song sounded with certain caps, then replace them with other and hour later retest with the new caps and tell the difference. I don't know how are there still people that believe that crap. But again, people buy Obscurum rocks and directional power cables, so untill there are sheep there will be wool.
@@mitkothemacedonian Seriously, my experience is based over about 8 yrs with cap testing, with many different amps, dacs, preamps, etc… results differ. Sometimes a bigger difference, sometimes a smaller difference in sound. Many of my customers have experienced what delusional change a cap can do😉👌
I got lens implants as well, 4 years ago. I went from +9.5 on each eye, to 0 (means I'm not wearing glasses anymore). I can confirm it's well worth it.
Do your cousin's lens implants flex to accommodate different focusing distances? I think some of the new ones are made to flex like the natural lens, in response to your eye's muscles, so they adjust somewhat for focus distance.
see my comment... those muscles are useless. brain somehow knows where to focus. those lenses are like fresnel lenses and depending on where you look through (automatic thing) brian knows what to focus on... strange thing.
@@murat.eraydin The muscles work until you pass 40 years of age or so. Then the lens loses flexibility and the muscles can't make it change shape anymore, so the lens doesn't adjust to different focal distances.
I thought the Monty Python thing was a funny break in the middle of the repair. I do have a serious question about dim bulb; what is the purpose and do you buy them or build them
@@BruceNitroxpro Well, they didn't have computers back then and all the schemos were hand drawn. Thousands of them over the course of just a couple of years. There were lots of "service bulletins" where many of the mistakes were rectified, but only "authorized" repair facilities got them. Although "some" were included as an "addendum" with some models, most were tossed as "eh, I don't need this"... My Sansui 9090DB came with the "updated" schemo, but back then I was one of those "dummies" that lost it. lol!
And yes...... yes you have lost your mind, but you're in good company so no worries. I actually had a chuckle when you stopped and said 'get on with it' but I do see it, far to often. Stupid arguments about speaker cable quality, keeping old ass leaky caps in tube amps for that "special sound"... ohhh it's a bumble bee cap that delivers the epic soundZZZ (never mind that I'm always replacing burnt out tubes).. and the list goes on...
Regarding de-soldering the transistors to re-apply heatsink compound. Are you not applying heat which will reduce their lifetime? Can you not just undo the screws and put heatsink on with them in situ ? Probably too much of a squeeze trying to undo the screws? Re dropping components on the floor. I'm thinking of sitting in a huge budgerigar tray. (The tray, not the budgerigar would be huge - I wouldn't use a huge budgerigar that would be cruel and pointless).
Ahh python, the madness is always enjoyable to watch :-D I imagine you might like "The upper class twit of the year show" very silly. The "Four Yorkshire men" (many versions) Each one trying to show how bad life was for them, one upmanship sillyness. "The Fish-Slapping Dance" obvious. And "Fawlty Towers" a t.v show about a mad hotel owner called basil Fawlty.
Hi Tony - what temp are you running your soldering iron in this type of situation? I'm liking that your dwell time on the component is low but joint is good. If you answered this before, sorry.
Hi Tony, I want to ask about the under biasing. Is it not the case that Pioneer biased it at at level where cross over distortion is lowest across all output levels. If we were to isolate the output stage, the Pioneer spec would yield best distortion, at the cost of dissipating more heat. Is it not the case that global negative feedback is making us see no cross over distortion at lower bias? Would we not bias each stage optimally and let the remaining budget of negative feedback correct other non linearities in the circuit? Thanks.
Funny. In the small number of schematics I've seen, the wires that terminate just short of an intersection with a little orthogonal stub denoted an underpass, or culvert, under the cross wire. Here that appears not to be the case. Maybe the artist forgot the local argot a couple of times? I used to say that the makers of equipment like old 64k modems and the like, or consumer receivers for that matter, would assign the user interface design to the new guy -- don't get me started on some of the idiocies. Maybe the published schematics fall to the same noob?
What was the deal with some of the vintage to3 transistors having a loose piece rattling inside but were just fine electrically. If I remember right was the sanken ones that did that. Anyone dissect and figure what that was.
@@MichaelBeeny Strange as I have come across a MARANTZ Class A amplifiers and they sound like you are in the studio they are that good but they cost 2-3,000£ or 3,000$-4,500$
@@DAVIDGREGORYKERR Marantz may well make a class A amplifier but I assumed your question was related to THIS amplifier under repair. The only real difference between class A and AB is bias. If you turn up the QI to remove cross over distortion enough, you have class AB which will sound the same as a class A but use a lot less power in the form of heat. If this amplifier WAS class A the heatsink would be enormous, so would the power transformer and cost. All for nothing!
You better off put it in micro-cap the circuit board diagram, and it would be interesting to run it as it is the schematic and see what waveforms you get! lol plus any upgrading you do to it is so easy in micro-cap see what's happening all free now. Hopefully you're supporting Louis rossmann on his right to repair bill to congress, how do you get away in your industry because medical equipment has a lot of restrictions independent repair shops on right to repair something you would be supporting I suppose. Fawlty Towers you must have watched Fawlty Towers Tony you might like Not the Nine oclock news Blackadder 80s and 90s I was wondering if you spray the circuit board both sides with a permanent dry silicone how does that change its dielectric properties should improve it What's your feeling on splitting the Mica maybe into three parts to add better thermal coupling!
2:00 --Could this schematic be MORE bass-ackward! Not only are the + rails BELOW the - rails, but the inputs are on the RIGHT and the outputs are on the LEFT!
I've paid to have an argument, so let's argue. No you haven't. Yes I have. No you haven't Yes I have. If I haven't, why are you arguing with me. I could be arguing on my spare time... But you're not arguing, you're just contradicting. No I'm not. Yes you are. ....
27:02 I always train my people to cut first. one part of the reason is just as you pointed out. the other reason is that there is the chance to lift up the pad (single sided mostly) by the physical impulse that is presented by the cutting action "snap". Also you provide less thermal inertia by cutting the leads off, so you can solder the components more quickly and do less thermal stress. *thumbs up*
Enjoyed your Monty Python references. Right after viewing this, I went right to the parrot sketch on UA-cam to watch it.
Hi Tony,
I really enjoyed your talking caps skit!
Cheers
Mark
i love your videos this one is the one i like the most thanks for the comady and good electronics work
Hi Tony, I've learned that you shall cut the leads before you solder, because the risk of weakening (cracking) the solder joint. I think it was mentioned that solder can break at only 10 grams.
Your arguing capacitors reminded me of "D-Lab Electronics" (UA-cam) that sometimes also make sketches as intros.
Another nice restauration, Tony! And, those old Monty Python comics are great fun!
"Your leaky." "No I'm not." "Your so leaky, you have a doctorate in anthropology"
Mary Leakey, I presume?
Hi Tony just started watching the video and when you got to the part about cataracts and laser or lasik surgery I thought I would jump in with my 2cents. I’m getting ready for my cataract surgery and in the preliminary eye exam there were questions regarding having any of the lasik or laser and how that would have a concern. Now I’m going with a mult-focal lense called Vivity it’s the latest lense on the market. Due to COVID-19 my health care provider is backed up for several months but I expect to have it done this summer. You may want to research this before making the final decision. Now I’ll be 66 then and will never need to replace them. Good luck and back to video for me
I must say that you bring a considerable amount of experience to your videos. Thank you for that.
Interesting that the power transistors use a common heatsink with separate sensor diodes for each channel. So if you were only driving one channel the QI on the other would also change the bias. In practice however, being a stereo amplifier both channels would see much the same average power output.
I had to think about this for a while, but I can see how this would work. All of the output transistors share a common heatsink. As such, they will all be at a common temperature. If the temperature of one channel increases, it will raise the temperature of the transistors of the other channel, which will affect the Vbe on them as well. The bias diodes are also common to the heatsink (temperature-wise), so they will change as well, which will keep the bias in order. This is a pretty common design on all of the mid-power amplifiers of this era. The higher-powered amplifiers will have a separate heatsink for each channel. Thanks for the comment!
Great Sunday evening session. Love the humor. Learning lots. Thanks for the look.
I was working on a SR7000g which also has the stabistors one lead broke off flush . took a dremmel tool with tiny diamond bit and ground away the epoxy around the lead enough to solder and re epoxy . Totally worth the trouble sounds great
I've done that too. The leads on those are fairly delicate.
regarding eye implants; I was using multifocal glasses for about 25 years, after researching a year, I went for Johnson&Johnson's top of the line implants (5 months ago). My eyes were over 4 in dioptry + astigmatism. Doc said he prefers not to go for correcting astigmatism and I opted. Results; I need good lightning to read and do precision work. 4000+ K lights are my friends now (i hate white light normally).
Other than that you will see halos (rings) around bright lights (especially LEDs), so driving at night is a little funny, stop lights and headlights disturbs a little, you feel like you are in Vegas :)
Because of those rings (or halos), contrast isn't that great (that's why you need good light). So 20/20 is not possible. But doc said it's about the brain, it will choose not to see those rings with time (they will be there but brain will ignore them)
Other than these, it's ok to go for it. I have replaced all of my eye glasses with sun glasses (8+) ;)
So make your choice with these in mind, do not take ads and doctor's sayings.
Hey Tony, there is a guy in Germany that has the STV-3HY stabistor diodes. I have used them myself in a few Sansui receivers and they work just fine. Littlediode in the U.K. sells them too, but at a little higher price.
Do you have any contact info for this German source, please?
@@richardmarshall6751 Here is their listing on eBay.. www.ebay.com/itm/324375836304
Having had cataract surgery several years ago, I can tell you not to wait. In time you may develop secondary cataracts, which are taken care of by a laser. I had that done on my left eye a couple of years ago. My right eye doesn't need the laser treatment yet. Insurance doesn't pay for Lasik, but it does pay for cataract surgery.
Like that dialogue between your two capacitors lol.
You have good taste in comedy Tony, the BBC produced some of the best in the 70's in my humble opinion
"Practice Safe Zenering" :)
I now have visions of you in a orange colored suit of armor straddling a capacitor/horse via Monty Python style skit. Thoose old BBC shows are still on PBS generally on Saturday night.
Tony interesting you showing the internals of the power transistor and compared it to those that are high quality ones. Those made in Japan are of very high quality. I am at the age where I remember when we in the US was complaining that Japan did not make good quality components. Well, it's a rarity to find stuff that says made in japan, let alone made in the USA. I have my doubts China would reach to the level of the same quality of what was made.
Another little "tip" for the transistors on the heat sinks. Unscrew the transistors (when feasible), then unscrew the heat sinks. Remove the heat sink without desoldering the transistors. That is as long as you know the transistors are good. If you need to replace the transistor, without the heat sink allows you to "wiggle" the transistor while desoldering with the Hakko making it easier to remove when the leads are folded over so bad. Wiggling the transistor towards the "fold" will lift it enough the Hakko can suck the solder up.
Like this idea.
My favorite was Tom and Barbara Goode and Margo and Jerry Ledbetter in The Goode Life
Tony, Monty Python +, I find this very interesting because I have a Pioneer SX737 that needs to be brought back to life. I am learning a lot of tips on what to do and what not to do. I'm very interested in your oscilloscope setup. I have tried to setup using a modern Chinese 50W audio amp driving across an 8 ohm wire wound ceramic resistor. The resistor is rated at 100W. I would appreciate it if you would give details about your setup in the next video. My setup is picking up a lot of noise. My experience in electronics dates back to my high school days back in the 60s. I dropped it as a hobby when I started in aviation for the next 48 years. Now that I'm retired I've picked it back up and having a lot of fun. Keep up your great video work, you are the best!
You crack me up! I love Monty Python!
27:30 I don't think that copper being exposed is any issue. Corrosion on copper has the special characteristic that it builds a protective coating on the surface of the copper that stops any further corrosion. It's not like rust on iron that just eats away on the metal until it's all rusted away.
That's why they used sheets of pure copper on the roofs of churches in the old days. It would corrode and turn green in the beginning, but then would stop corroding and then last almost forever without the need for any maintenance.
You'd love the "Brontosaurus theory of miss Elk" skit.
That’s so crazy that the schematics are wrong right from the start! Knowledge is power. Nice job Tony 😃
When I build gear, and I build a lot of recording equipment, I don't like to bend the leads over on the solder side for most common components. I don't like to do it so it's easier to desolder, should I, or another tech have to do it in the future.
great video , specially leaking capacitor fighting
@46:52 bending lead at direction of track ,, is acutely IPC -A-610 , so Tony you are making it right
Whoa! Lots to comment on in this video!
Who doesn't love all the Monty Python stuff? The Life Of Brian is still one of my favourite! I was showing my kids the bigges dickes scene just a few days ago LoL. Your voice acting was spot on! I definitely had a good laugh 😂.
Eye surgery might appear to be way off topic but try doing this sort of work with your eyes closed! I think that it's part and parcel of this profession! I had really good eyes till I was just over 40 something and then my ability to focus on things near and far went up the proverbial creek without a paddle! I need two different pairs of glasses now, one to see things up close and the other to see everything else, the only time I I don't need glasses to see is when I'm asleep and having a dream, strangely though, it appears that the dream that I'm seeing is actually being seen with my eye's, almost like the eye's are both the receiver and the processor of vision! In when the image gets processed and shipped out into memory and then later recalled to the eye's, reprocessed, CGI added and then resent into storage! Yeah! Dreams are really strange!
And finally, that potentiometer, you mentioned a loudness tap? I know that I have given who a loudness circuit would be controlled but that was a very long time ago and haven't really thought about it since. Does that potentiometer have three pot's inside it or something? This isn't something that is discussed much, more like there's nothing on UA-cam on this topic alone! Another circuit that has always fascinated me is the stereo wide circuit that was fitted to many boomboxes throughout the 70's and 80's, I have tried to search for that type of circuit but I haven't really found one. My boombox used a switch and gave a choice of mono/stereo/stereo wide, but there were some that had a potentiometer where you could continually adjust to what sounded best but as I said earlier, I have yet to find such a circuit diagram anywhere...
Capacitors capacitors capacitors! It's a never ending topic!
I watched a recent video on a subwoofer amplifier repair, I watched as the person went through checking capacitors in circuit with his Bob Parker ESR meter and claiming that they are all excellent even though he himself mentioned that a few of them were expanded! He's a great guy and works on a lot of interesting things but I often find myself screaming at the screen out of frustration! Why have a lot of people fallen into the ESR trap?
There's just no easy way around it! The only thing that an in circuit ESR tester is actually good for is checking capacitors in the power supply where ESR is a critical factor and the other is seeing if a capacitor in circuit is failed open or short!
Leakage or EPR or Vloss or disapation or whatever you want to call it can only be measured out of circuit! There's no free lunch! They have to come out to be checked otherwise you have no idea of their actual condition! And when it comes to replacing capacitors, I have a golden rule!
If I value the equipment that I'm working on, it takes longer but I always check to see if I can get a higher voltage rated capacitor at the same capacity to fit in the same location, especially if it is located next or near a heat source!!!
This golden rule will ensure that the equipment will live a lot longer than what it already has!
When it comes to old capacitors like the paper in wax, I saw a video in where RCA Victor was testing those things at twice their rated voltage!
Think about that for a minute! It's rating printed on it's side is probably 400V but they are putting 800V across it, try that with today's capacitors!!! I dare you!
And if anyone has been following Mr Carlson's Lab, would have seen him test capacitors on old Heathkit and various other old test equipment, and you would have seen that even a bad capacitor only start's showing it's point of failure at the top end of it's voltage rating! This I believe is the same failure mode of modern capacitors also! They always fail from top down!
So then! If you go up in voltage on the replacement capacitor, it's going to last a lot longer than the original one! And going up in voltage also means it's going to be physically larger and provide both better thermal insulation and disapation at the same time, an 85°C rated capacitor at 350V will be like 105°C rated capacitor when used in a 50V circuit (the voltages are just a hypothetical situation) but I'm sure that you get my point, if you have a look at the Panasonic capacitor datasheet, you can see that this effect is true and correct. I just want to see all ESR meters banished, to many people are using them incorrectly and teaching everyone else this bad practice! This is giving the industry a bad name!
The customer has watched someone go over the equipment with an ESR meter on a many videos and now wants to know why you took so long? Do you want it repaired or do you feel like bringing it back in a month's time to spend some more money on it?
Yeah I'm ranting but capacitors are a touchy topic for me!
I'm just trying to get the awareness out there that there's a better way to do it, going by this golden rule, you can get away with using no name brand capacitors and still get great long life performance at a cheaper price for the budget conscious customer! You don't want to be working on the same equipment that you have already worked on! You want the customer to bring new challenges and know that they trust you to do the right thing!
Now! That's all done ✅
Transistors!!! Have you ever tried to connect that TO3 that you have opened up it's case and connected it to the scope and see what happens when you shine a light on it's die? It's supposed to behave like a tiny solar panel, I wonder what sort of power it could put out? Same thing happens when you shine a light on an led! Although it's not very efficient at producing as it is emitting! It's a great experiment that a lot of people don't know that transistors and LEDs are able to do this, kinda like a speaker which can also be a microphone!
Technically an optocoupler is the transistor that is being controlled by light!
British speaking capacitors have now become the new fuel for my nightmares. ;-)
I think the Elna caps your referring to Tony is the Silmic II types. Great for audio and my first choice over the Nichicon gold types but larger values can be too big for certain applications, which is the only draw back.
In Sweden when i was young i learned that you always cut the leads when you repair/ manufacture military equipment. Since i heard that (30 yrs ago) i've done it everyday and i've seen some amps i've repaired/ restored have had issues with corrosion when leads been cut after soldering so yes you're doing the right thing.
Another thing; Try out Elna Silmic II, available from mouser and digikey. I've done sound comparions and i rank the caps in this order;
1. Elna Silmic II . Warm sounding with good detail, almost like a filmcap. Elna Cerafine; Very clear and detailed but can be too clear. Can do wonders sometimes. Cerafine hard to get.
2. Nichicon KZ "Muse" I call this the Rock n' roll cap. Big and bould sound.
3. ES " Muse" (green ones) Bipolar.
4. Fine gold (Neutral but a bit boring) Above ones are most better for signalpath.
5. FW - Yamaha uses tones of these and Fine gold in their new premium amps btw..
6. KA (blue sleeve as KT)
7. KT (KT is actually worse/older version of KA) -Use KA when you can.
-Nippon has a audiocap that being used by Sony, Yamaha and others, Nippon ASG.
-Never use Nichicon VR/VZ in signalpath. Horrible dark sound and no bass.
Arcotronics/ Kemet R-series are ofcourse better when they fit. Actually prefer them instead of Wima MKS. But the best is nos ROE (Roederstein) for example MKT 1813/1818/1822/1826.
You're a fun dude. Good videos. Learned a lot.
Many thx!
You are absolutely delusional with those remarks that you can remember how a song sounded with certain caps, then replace them with other and hour later retest with the new caps and tell the difference. I don't know how are there still people that believe that crap. But again, people buy Obscurum rocks and directional power cables, so untill there are sheep there will be wool.
@@mitkothemacedonian Delusional?
😂 I’m a magician
@@mitkothemacedonian
Seriously, my experience is based over about 8 yrs with cap testing, with many different amps, dacs, preamps, etc… results differ. Sometimes a bigger difference, sometimes a smaller difference in sound.
Many of my customers have experienced what delusional change a cap can do😉👌
I got lens implants as well, 4 years ago. I went from +9.5 on each eye, to 0 (means I'm not wearing glasses anymore). I can confirm it's well worth it.
9:00 - Curious how C801 and C802 aren't identical values!
Nobody expects the Spanish Inquisition!
Do your cousin's lens implants flex to accommodate different focusing distances? I think some of the new ones are made to flex like the natural lens, in response to your eye's muscles, so they adjust somewhat for focus distance.
see my comment... those muscles are useless. brain somehow knows where to focus. those lenses are like fresnel lenses and depending on where you look through (automatic thing) brian knows what to focus on... strange thing.
@@murat.eraydin The muscles work until you pass 40 years of age or so. Then the lens loses flexibility and the muscles can't make it change shape anymore, so the lens doesn't adjust to different focal distances.
Tony, Have you worked on any Luxman equipment of this era?
I thought the Monty Python thing was a funny break in the middle of the repair. I do have a serious question about dim bulb; what is the purpose and do you buy them or build them
Some one had Schematitus when they drew this one 🤓🇬🇧
LOL! Marantz schematics are well known to have lots of mistakes. Many on-board silkscreen mistakes too. And it's not limited to Marantz.
@@JeffCounsil-rp4qv , But this is ridiculous! I mean, this went to users! God knows what they were thinking... or NOT thinking!
@@BruceNitroxpro Well, they didn't have computers back then and all the schemos were hand drawn. Thousands of them over the course of just a couple of years. There were lots of "service bulletins" where many of the mistakes were rectified, but only "authorized" repair facilities got them. Although "some" were included as an "addendum" with some models, most were tossed as "eh, I don't need this"... My Sansui 9090DB came with the "updated" schemo, but back then I was one of those "dummies" that lost it. lol!
don't worry be happy Very Good Job
If biased at 30, any guess at what the power would have been?
Keep the offtopic stuff on, makes an hour video interesting and watchable, I won't finish one of this videos if it were 80 % silence, cheers Tony!
Great content!
Can you elaborate on the ALPS pot? .Where to purchase and perhaps part number?
Cheers!
EBay, lots of suppliers, some mounted on PCBs. Part number depends on value of resistance, log/lin etc. Like ANY make or type of pot.
potentiometers.com is a great resource to find replacement pots
And yes...... yes you have lost your mind, but you're in good company so no worries. I actually had a chuckle when you stopped and said 'get on with it' but I do see it, far to often. Stupid arguments about speaker cable quality, keeping old ass leaky caps in tube amps for that "special sound"... ohhh it's a bumble bee cap that delivers the epic soundZZZ (never mind that I'm always replacing burnt out tubes).. and the list goes on...
Regarding de-soldering the transistors to re-apply heatsink compound. Are you not applying heat which will reduce their lifetime? Can you not just undo the screws and put heatsink on with them in situ ? Probably too much of a squeeze trying to undo the screws? Re dropping components on the floor. I'm thinking of sitting in a huge budgerigar tray. (The tray, not the budgerigar would be huge - I wouldn't use a huge budgerigar that would be cruel and pointless).
Going up!
Ahh python, the madness is always enjoyable to watch :-D
I imagine you might like "The upper class twit of the year show" very silly.
The "Four Yorkshire men" (many versions) Each one trying to show how bad life was for them, one upmanship sillyness.
"The Fish-Slapping Dance" obvious.
And "Fawlty Towers" a t.v show about a mad hotel owner called basil Fawlty.
They OHMitted the 5 watt resistor on the schematic??
Hi Tony - what temp are you running your soldering iron in this type of situation? I'm liking that your dwell time on the component is low but joint is good. If you answered this before, sorry.
What is odd is that 40.2V - 14V = 26.2V. I wonder if that diode is actually some kind of a voltage dropper somehow (time 4:13)
I believe its a 14v Zener.
Hi Tony, I want to ask about the under biasing. Is it not the case that Pioneer biased it at at level where cross over distortion is lowest across all output levels. If we were to isolate the output stage, the Pioneer spec would yield best distortion, at the cost of dissipating more heat. Is it not the case that global negative feedback is making us see no cross over distortion at lower bias? Would we not bias each stage optimally and let the remaining budget of negative feedback correct other non linearities in the circuit? Thanks.
Will you be publishing the updated schematics someplace?
Do you also remember "Spitting image"??
Funny. In the small number of schematics I've seen, the wires that terminate just short of an intersection with a little orthogonal stub denoted an underpass, or culvert, under the cross wire. Here that appears not to be the case. Maybe the artist forgot the local argot a couple of times? I used to say that the makers of equipment like old 64k modems and the like, or consumer receivers for that matter, would assign the user interface design to the new guy -- don't get me started on some of the idiocies. Maybe the published schematics fall to the same noob?
Nice job
Ok Tony now 30 min in I don’t know if you have lost it or I’m going crazy lol. Talking caps lol
What was the deal with some of the vintage to3 transistors having a loose piece rattling inside but were just fine electrically. If I remember right was the sanken ones that did that. Anyone dissect and figure what that was.
Tony, if you like the British comedy, look for a show on Netfix called "Still Game" you'll love it.
Which class is this amplifier? Is this a Class A, Class B, Class AB, or another type of amplifier?
I prefer my capacitators fried, with ketchup
is it a Class A amplifier as the MARANTZ is a very good make
No, it's class AB the heatsinks would need to be many times bigger for class A
@@MichaelBeeny Strange as I have come across a MARANTZ Class A amplifiers and they sound like you are in the studio they are that good but they cost 2-3,000£ or 3,000$-4,500$
@@DAVIDGREGORYKERR Marantz may well make a class A amplifier but I assumed your question was related to THIS amplifier under repair. The only real difference between class A and AB is bias. If you turn up the QI to remove cross over distortion enough, you have class AB which will sound the same as a class A but use a lot less power in the form of heat. If this amplifier WAS class A the heatsink would be enormous, so would the power transformer and cost. All for nothing!
Hyacinth Bucket is your fan (pronounced bouquet...)
Benny Hill also.
You better off put it in micro-cap the circuit board diagram, and it would be interesting to run it as it is the schematic and see what waveforms you get! lol
plus any upgrading you do to it is so easy in micro-cap see what's happening all free now.
Hopefully you're supporting Louis rossmann on his right to repair bill to congress, how do you get away in your industry because medical equipment has a lot of restrictions independent repair shops on right to repair something you would be supporting I suppose.
Fawlty Towers you must have watched Fawlty Towers Tony you might like Not the Nine oclock news Blackadder 80s and 90s
I was wondering if you spray the circuit board both sides with a permanent dry silicone how does that change its dielectric properties should improve it
What's your feeling on splitting the Mica maybe into three parts to add better thermal coupling!
I remember them all ! the WOKE community would go mad nowadays, way to risqué !...cheers.
2:00 --Could this schematic be MORE bass-ackward! Not only are the + rails BELOW the - rails, but the inputs are on the RIGHT and the outputs are on the LEFT!
Sorry Tony I should have known.
Clicking sound is me trying to subscribe AGAIN.Further I will not go in this venue.
Monty python was awesome. Half of your viewers probably don't know who he was Benny hill was great also
It's just a flesh wound!
I've paid to have an argument, so let's argue.
No you haven't.
Yes I have.
No you haven't
Yes I have. If I haven't, why are you arguing with me.
I could be arguing on my spare time...
But you're not arguing, you're just contradicting.
No I'm not.
Yes you are.
....
Your hands are trembling....you should see a doctor and fast...this may be a Parkinsons disease starting and you should have controlled medicine
How about a silly walk.
Yup.. Stavistors. Stv bias diodes.