0:00 Intro 0:20 Thank you! 0:44 Thermal Fuse talk 4:39 Removing the transformer for testing/repair 6:05 Transformer disassembly and talking about failure modes & design 9:41 Looking for the thermal fuse (and finding it!) 16:08 Bypassing the faulty thermal fuse & reassembly 24:16 A visit from our furry friend Mango ☺ 25:31 Cleaning up the rust and flaking paint 27:18 Testing the transformer & more transformer talk
I'm 26 years out from my BSEE and really didn't use it in my career, but when you go through ELI the ICE man theory, it all comes back! I can littlerally visualize my professor going through E101 material. That's a pretty cool feeling, and it brings me back to my youth! Great work, sir!
Repaired a Peavey guitar amp years ago for a friend. Same problem, a thermal fuse in the transformer blew and I had to remove the top few layers of insulation to repair the fuse. Bastard of a setup!
Tony, thank you for taking time to explain "power factor". Hams and RF engineers use SWR to basically explain the same thing, except that we are not restricted to only one frequency ie. 60Hz I'm sure that AC mains power factor can be shown on a Smith chart just like RF, but electricians probably don't do this complexity because it's unnecessary. As always, maximum power transfer occurs when the load is matched to the source...no matter what the frequency. 73 & keep up the great work.
found a defective thermal fuse in my neighbor's sprinkle timer and ever since then the whole street thinks i'm a genius and a life saver :)) his 'guy' didn't have an opening for like 2 weeks and it's like a contest here to keep the lawn lush, in the summer, in the desert. it's insane.
My KA9100 amplifier self-oscillated and the transformer died. It was not under heavy use. Now I know there is a fuse, but now the speaker terminals are crumbled. Thanks!
IM RETIRED BUT WORKED IN A POWER STATION AND THE TRANSFORMERS WE HAVE ARE AS BIG AS YOUR HOUSE, STEP UP TO THE GRID, OIL COOLED WITH A NITROGEN BLANKET, THE OIL WAS TESTED EVERY OUTAGE TO CHECK FOR SHALACK BREAK DOWN. THANK-YOU TONY FOR YOUR WORK !!
Even for an experienced Engineer/Technician like yourself Tony, having many onlookers can aid our ability to solve a problem much more quickly. When immersed in a job, we don't always see all the possibilities as we often mull over too many other possibilities. Assessing and fixing can be a like searching for a needle in a haystack, however, sometimes we shouldn't be looking for just needles. I'm enjoying this video! 5 Stars!
Wow.. Although I have heard of some transformers having thermal fuses.. I totally forgot about that. Glad a few sharp viewers caught that! Ended up being a relatively simple fix AND a "AH HA"! moment. Not to me to mention some good explanation of eddy currents, VA, power factor, and where losses come from. Excellent video Tony! Thank you!
Tony! As far as I'm concerned, you really should be thankful for who you are! There are others who also repair equipment and I along with other people have tried to get across something important and the content creator either shrugs it off or doesn't believe what the comments section is trying to tell them! I once pointed out to Techmoan that the erase head in the boombox he was showing was a permanent magnet type and they are responsible for inducing noise into a recording on a cassette tape, some boomboxes used AC biased erase head's like the majority of home hi-fi cassette decks... Well in the next video he mentioned the erase head and type and that someone mentioned it in the comments section but didn't say who! And I felt like he was talking directly to me! It's hard not to admire and be a fan of people like that... Had he actually mentioned my name! I would have fallen over! I can't believe how quick I get a response from Big Clive even though I just left a comment to a video from 5 years ago... He's awesome! Off Grid Garage channel for all your solar system information and entertainment has also made mention of things that I have brought up.... And I swear that he's named some of his solar equipment after me due to not being able to pronounce the Chinese name of it LoL... Had you not had the willingness to let the community the ability to participate, this amplifier would have ended up in the part's bin... And I was going to suggest that if you were going to swap out the transformers, and the amplifier ic was also finished, I would have loved to see you have another go at that eBay DIY quasi complimentary amplifier that you built some years ago but didn't like when completed... I called it the amplifier that beat the mighty Tony B... I really wanted to see you have a go at it and see if you could improve it! I loved the sound of the word quasi complimentary and the fact that it was using metal encapsulated TO3's.... So I purchased 4 or more of them but I have never put one together after you said that you didn't like it! I have been hoping that someone will fix it but there's been nothing thus far... I know enough about a lot of things but not enough to know exactly where in the circuit I will need to focus on to correct or adjust what I'm hearing or measuring at the output... I have all these shiny 2N3055's waiting patiently to be used but not in something that sounds terrible.... Thanks Tony once again for everything you do buddy.
Just an FYI, you can cut that copper band if necessary and then solder it back together. If fact somewhere in there the band is already soldered together.
Greetings. I am extremely grateful to you for your detailed dedication, patience, for those of us who are starting with the application of this exciting hobby. At this moment in my life and entering an age of 60 years, after a long time of saving I have been able to acquire a dream equipment for many years (Vintage integrated hi fi amplifier) and that for me is expensive because I have to import it. I learn from you so that when the equipment arrives I can provide maintenance and repair if necessary. Wishing you and your family are always well.
Great news! Hooray for TH-cam people! Thanks Tony for transformer lesson. I learned about ELI THE ICE MAN back in the mid 70’s while in basic training for the Air Force and I’m forgetting a lot of it. Looking forward to more in this series
Viste Tony, que tenia un fusible interno, en los equipos viejos casi siempre le ponían un fusible a los transformadores, por lo menos Technics, Sansui Pioneer y otras marcas mas lo hacían, ahora no lo hacen, claro hay otras formas de protección en los equipos actuales, que bien. Lo que no me gusta de ese amplificador es que usa ese IC para la etapa de potencia, prefiero lo discreto, sus transistores.
Tony, I'm glad you're going to restore and return that gen to another maybe half century of useful service! They don't make them that good anymore, unless you're willing to spring for an equivalent Accu-Phase unit that costs gazillions of bucks (and probably uses about the same design).
I looked up the TA-100WA darlington output modules, and the circuit is very simple with few parts. I would crack the case open to check for an easy repair.
Actually, I thought about a possibly open thermal fuse.. It wasn't so very hard to get to. If you wanted, you probably could have somehow fitted a replacement, but would not be necessary. Regarding apparent and real power, good explanation! As a kid I wanted to test a transformer before putting the core in.. Put a scorch mark on the table.. Later I learned about power factor and electrical calculations, have studied, later taught this for students in University several years..
I've repaired many a transformer with blown thermal fuses, but always replaced them, not bypassed them. I would be afraid of any liability after the customer burns his house down!
Wow, you really have skills to sort out the problem on that transformer. I have the same amplfier and I want to replace one of the big radiator "heatsink". Is it hard to unglue the rads from the back of the TA-100WA module. Did the thermal paste is hard to the point I could damage the module?
Congratulations Tony, I am glad you were able to repair the original transformer. I think it will be a nice restoration project overall. I am looking forward to seeing the new 'Darlington Power Packs' too. At 21m59s please inform the name (and brand if you know) of the yellowish tape you use for insulation. I need to buy that for a similar project. Thank you.
Your "transformer talk" took me back to the year 1980 when I learned "electro-magnetic impedance". Not a lot of folks know WHY the lamination's are electrically insulated from each other unless they had to learn the mathematics behind it. Did you mention why that sheet of pure copper is wrapped around the core? When you see HUGE capacitors strapped to a telephone-pole, it is to bring the Power-Factor closer to zero. (power-company cannot accurately measure your REAL power) then, there is hysteresis.
Tony I've never disagreed with you once but pulling that second transformer out for cosmetics but leaving that old thermistor in it while it's already on the bench seems like a bad idea to me...
But why didn't Kenwood indicate the thermal fuse inside the transformers on the schematics? You would think that would be useful information for someone servicing one of these units...
Those thermal fuses in transformers really piss me off. They could at least put them on the outer surface, or just behind the tape. So often they don't, and you stand a chance of ruining the transformer completely when you try to repair it. I had a transformer in a Sony amp that had a failed thermal fuse buried in the windings that had failed for no reason. Had to find a donor amp to fix that one, as there was no chance of repairing it. Awful, irritating, pointless things that facilitate planned obsolescence.
Thermal fuses as the name goes must act/ protect when they are heated beyond a particular temp. (it's mentioned on the fuse) Hence they are embedded in between the windings..It detects when the wdg. temp. is too high .. irrespective of the current .
![[#SHORTS CLIP] ครูอึ้ง กรรมการอึ้ง ฮ่าๆ l ซานิเบาได้เบา l One Playground](http://i.ytimg.com/vi/qeBTuMJs4t0/mqdefault.jpg)
0:00 Intro
0:20 Thank you!
0:44 Thermal Fuse talk
4:39 Removing the transformer for testing/repair
6:05 Transformer disassembly and talking about failure modes & design
9:41 Looking for the thermal fuse (and finding it!)
16:08 Bypassing the faulty thermal fuse & reassembly
24:16 A visit from our furry friend Mango ☺
25:31 Cleaning up the rust and flaking paint
27:18 Testing the transformer & more transformer talk
Right from the start, we knew you were going to take the other transformer out too to clean it up 😁
Me too. 🤘
I'm 26 years out from my BSEE and really didn't use it in my career, but when you go through ELI the ICE man theory, it all comes back! I can littlerally visualize my professor going through E101 material. That's a pretty cool feeling, and it brings me back to my youth! Great work, sir!
ELI the ICE man is good, but I was taught to be CIVIL - C (capacitor) I before V, V before I for L (inductor). 😊
Repaired a Peavey guitar amp years ago for a friend. Same problem, a thermal fuse in the transformer blew and I had to remove the top few layers of insulation to repair the fuse. Bastard of a setup!
Tony, thank you for taking time to explain "power factor". Hams and RF engineers use SWR to basically explain the same thing, except that we are not restricted to only one frequency ie. 60Hz I'm sure that AC mains power factor can be shown on a Smith chart just like RF, but electricians probably don't do this complexity because it's unnecessary. As always, maximum power transfer occurs when the load is matched to the source...no matter what the frequency. 73 & keep up the great work.
Talking about RF, here an old antenna matching tutorial:
th-cam.com/video/JHSPRcRgmOw/w-d-xo.html
Would of never guessed tf was the problem, good fix. Great session, thanks for the work you put in for us.
CAT Scan shows transformer ready to rock.
Excellent. Love your channel.All the best from Scotland 🏴
found a defective thermal fuse in my neighbor's sprinkle timer and ever since then the whole street thinks i'm a genius and a life saver :))
his 'guy' didn't have an opening for like 2 weeks and it's like a contest here to keep the lawn lush, in the summer, in the desert. it's insane.
My KA9100 amplifier self-oscillated and the transformer died. It was not under heavy use. Now I know there is a fuse, but now the speaker terminals are crumbled. Thanks!
Thanks! Always had these questions about transformers, but never spent the time to find the answers.
Hooray! Glad to see you went ahead with it!
IM RETIRED BUT WORKED IN A POWER STATION AND THE TRANSFORMERS WE HAVE ARE AS BIG AS YOUR HOUSE, STEP UP TO THE GRID, OIL COOLED WITH A NITROGEN BLANKET, THE OIL WAS TESTED EVERY OUTAGE TO CHECK FOR SHALACK BREAK DOWN. THANK-YOU TONY FOR YOUR WORK !!
glad to see another amp will be saved from the landfill can't wait for the part 3 video thanks Tony
Even for an experienced Engineer/Technician like yourself Tony, having many onlookers can aid our ability to solve a problem much more quickly. When immersed in a job, we don't always see all the possibilities as we often mull over too many other possibilities.
Assessing and fixing can be a like searching for a needle in a haystack, however, sometimes we shouldn't be looking for just needles.
I'm enjoying this video! 5 Stars!
Wow.. Although I have heard of some transformers having thermal fuses.. I totally forgot about that. Glad a few sharp viewers caught that! Ended up being a relatively simple fix AND a "AH HA"! moment. Not to me to mention some good explanation of eddy currents, VA, power factor, and where losses come from. Excellent video Tony! Thank you!
Tony! As far as I'm concerned, you really should be thankful for who you are!
There are others who also repair equipment and I along with other people have tried to get across something important and the content creator either shrugs it off or doesn't believe what the comments section is trying to tell them!
I once pointed out to Techmoan that the erase head in the boombox he was showing was a permanent magnet type and they are responsible for inducing noise into a recording on a cassette tape, some boomboxes used AC biased erase head's like the majority of home hi-fi cassette decks...
Well in the next video he mentioned the erase head and type and that someone mentioned it in the comments section but didn't say who! And I felt like he was talking directly to me! It's hard not to admire and be a fan of people like that... Had he actually mentioned my name! I would have fallen over!
I can't believe how quick I get a response from Big Clive even though I just left a comment to a video from 5 years ago... He's awesome!
Off Grid Garage channel for all your solar system information and entertainment has also made mention of things that I have brought up.... And I swear that he's named some of his solar equipment after me due to not being able to pronounce the Chinese name of it LoL...
Had you not had the willingness to let the community the ability to participate, this amplifier would have ended up in the part's bin...
And I was going to suggest that if you were going to swap out the transformers, and the amplifier ic was also finished, I would have loved to see you have another go at that eBay DIY quasi complimentary amplifier that you built some years ago but didn't like when completed... I called it the amplifier that beat the mighty Tony B... I really wanted to see you have a go at it and see if you could improve it!
I loved the sound of the word quasi complimentary and the fact that it was using metal encapsulated TO3's.... So I purchased 4 or more of them but I have never put one together after you said that you didn't like it! I have been hoping that someone will fix it but there's been nothing thus far...
I know enough about a lot of things but not enough to know exactly where in the circuit I will need to focus on to correct or adjust what I'm hearing or measuring at the output...
I have all these shiny 2N3055's waiting patiently to be used but not in something that sounds terrible....
Thanks Tony once again for everything you do buddy.
Just an FYI, you can cut that copper band if necessary and then solder it back together. If fact somewhere in there the band is already soldered together.
Greetings. I am extremely grateful to you for your detailed dedication, patience, for those of us who are starting with the application of this exciting hobby. At this moment in my life and entering an age of 60 years, after a long time of saving I have been able to acquire a dream equipment for many years (Vintage integrated hi fi amplifier) and that for me is expensive because I have to import it. I learn from you so that when the equipment arrives I can provide maintenance and repair if necessary. Wishing you and your family are always well.
Great news. I had forgotten about ol' ELI since the late '70s, so thanks for the reminder. Another interesting show, thanks.
I feel transformed after watching this video. Thank you. Mike. 😄
It's the primary and secondary reason I did this video in the first place. ;)
Learned a lot in 40min. I knew a lot of this back in school but haven't used it in 35yrs. Thanks for the interesting video!
thank you Tony for doing this - I'm still learning and you are an excellent teacher!
Great news! Hooray for TH-cam people! Thanks Tony for transformer lesson. I learned about ELI THE ICE MAN back in the mid 70’s while in basic training for the Air Force and I’m forgetting a lot of it. Looking forward to more in this series
Viste Tony, que tenia un fusible interno, en los equipos viejos casi siempre le ponían un fusible a los transformadores, por lo menos Technics, Sansui Pioneer y otras marcas mas lo hacían, ahora no lo hacen, claro hay otras formas de protección en los equipos actuales, que bien. Lo que no me gusta de ese amplificador es que usa ese IC para la etapa de potencia, prefiero lo discreto, sus transistores.
That was a fiddly repair process. Good to see you have the patience, steady hands and calm nerves to do it. 👍🏻
Tony, Amazon sells a thermal fuse kit, I have replaced many of these over the years.
Excellent to follow you doing this transformer repair. Looking forward to part 3!
Thanks Tony for sharing the love….and the info. 👍👍🙏
Thanks for all the info Tony, it's something to fill my brain with in this hobby of mine now I'm in retirement.👍🏻
Nice real time repair!
Thanks Tony, for your detailed explanations here! I'm learning a lot, and you make it very easy to follow along! Thumbs up!
Great job explaing VA vs watts. Thanks
I love these kinds of videos. 😊
You & TH-cam Rock ✌🏼
Wow, that was an education on transformers for this novice, glad you did that all that!
That's good they added thermal fuses. Protects transformer and amp
Merci for this video. Good job!
Good Job Tony!
Great work Tony, I don't think I would be able to resist removing the fuse on the other channel to even things up, even though it would be a PITA 😊
Tony, I'm glad you're going to restore and return that gen to another maybe half century of useful service! They don't make them that good anymore, unless you're willing to spring for an equivalent Accu-Phase unit that costs gazillions of bucks (and probably uses about the same design).
I looked up the TA-100WA darlington output modules, and the circuit is very simple with few parts.
I would crack the case open to check for an easy repair.
Or just swap them out for some modern IRS2092 boards?
Looks great and I have also save some audio gear power transformers the same way as this one !
Great job.
Actually, I thought about a possibly open thermal fuse.. It wasn't so very hard to get to. If you wanted, you probably could have somehow fitted a replacement, but would not be necessary. Regarding apparent and real power, good explanation! As a kid I wanted to test a transformer before putting the core in.. Put a scorch mark on the table.. Later I learned about power factor and electrical calculations, have studied, later taught this for students in University several years..
Woot!
awww cute cat..
Wow
I've repaired many a transformer with blown thermal fuses, but always replaced them, not bypassed them. I would be afraid of any liability after the customer burns his house down!
Wow, you really have skills to sort out the problem on that transformer. I have the same amplfier and I want to replace one of the big radiator "heatsink". Is it hard to unglue the rads from the back of the TA-100WA module. Did the thermal paste is hard to the point I could damage the module?
My vintage Harman Kardon tube amp. The main transformer gets hot to touch can barely hold palm on it.
Looks like (from your last video) that someone replaced the "glass fuse" with a higher current rating and that in turn "waxed" the transformer.
You might check the meters for proper operation. That bent front panel must have been quite a blow.
What did we do before lazy Susans ?❤🎉
Scratch the bench! Lol
Congratulations Tony, I am glad you were able to repair the original transformer. I think it will be a nice restoration project overall. I am looking forward to seeing the new 'Darlington Power Packs' too. At 21m59s please inform the name (and brand if you know) of the yellowish tape you use for insulation. I need to buy that for a similar project. Thank you.
Kapton tape.
@@rogerknapman1260 Thank you. Much appreciated!
TH-cam should require every video to include at least one kitty.
Many of us techs have little furry friends as assistants.
Your "transformer talk" took me back to the year 1980 when I learned "electro-magnetic impedance". Not a lot of folks know WHY the lamination's are electrically insulated from each other unless they had to learn the mathematics behind it. Did you mention why that sheet of pure copper is wrapped around the core? When you see HUGE capacitors strapped to a telephone-pole, it is to bring the Power-Factor closer to zero. (power-company cannot accurately measure your REAL power) then, there is hysteresis.
Technically, it's not B+ B-, as it's not valve state. It would be more common to call it the VCC/VEE line
Just bought a flea market find piece of stereo gear that turned out to be MISSING its power transformer. There's no coming back from that.
Figure out what voltages it needs and fit a few Mean Well modules in there.
Tony I've never disagreed with you once but pulling that second transformer out for cosmetics but leaving that old thermistor in it while it's already on the bench seems like a bad idea to me...
But why didn't Kenwood indicate the thermal fuse inside the transformers on the schematics?
You would think that would be useful information for someone servicing one of these units...
Some do and some don't
Older devices show them sometimes, they're usually a given in Solid State electronics
fuses don't pop they go open and clear the fault a fuse that pops means that the fuse has failed and did not clear the fault and may have flash over
Those thermal fuses in transformers really piss me off. They could at least put them on the outer surface, or just behind the tape. So often they don't, and you stand a chance of ruining the transformer completely when you try to repair it. I had a transformer in a Sony amp that had a failed thermal fuse buried in the windings that had failed for no reason. Had to find a donor amp to fix that one, as there was no chance of repairing it. Awful, irritating, pointless things that facilitate planned obsolescence.
Thermal fuses as the name goes must act/ protect when they are heated beyond a particular temp. (it's mentioned on the fuse)
Hence they are embedded in between the windings..It detects when the wdg. temp. is too high .. irrespective of the current .
The "power-factor" value is just the "cosine" of the angle difference between the voltage and current.
Now if I only knew what a cosine was.... ;)
@@xraytonyb you're a riot...a regular riot.☺