Hey Mark. I have a B&K 1550 bench supply I suspect got wacked by an inductive load. It's been sitting for years. I almost threw it away because I couldn't find a schematic for it. You inspired me, so today I dug into it and found a shorted FET that switches the output on and off. Replaced it with a similar part I had on hand, and it works perfectly. Love your show. Thank you!
72 year old ex repair guy from the 80,s . Only things I can add are use capton tape around before air gun desoldering and a drop of liquid flux on the pins to help desoldering . What amazes me most is your dogged patience . I would have thrown half the stuff out the window ........................... respect !
The attention to detail while filming is amazing. I can't imagine how many times you have to move between shots just to show a bolt being unscrewed. Excellent production value, guess you go 110% on everything you do. Congrats.
if there were more people like you, the world would be a much better place. While i am interested in what you're doing, who you are as a person is why i keep coming back. All the best from Australia mate
Sliding it back onto the shelf, and the moment when you push it back and forth a few times just for the joy of hearing the rubber feet squeak... small things like that make life worth living. You are my favorite Internet technician with your deep and useful skill set, the cheerful and dogged determination with which you attack any problem, and your respect for vintage electronics... even a few things we recognized as 'cheaply made' back in the day. You shrug with every new challenge, fix it right, repair the hinges and recast the knobs. You give it your all which exceeds 150%.
Sir I have been a tech retired worked for 40 years. You are a natural. Very bright and the fastest I have seen at troubleshooting. You are still young I hope you get rich. W5DN
Between the 25 quid for the replacement chip and the value of his time… well, it *might* be less expensive than buying a new one, it is after all a 1200W jobbie, but I wouldn’t put money on it.
It's amazing to think that Mark's skills include the knowledge to diagnose and repair his own test equipment. Warranties on electronics mean nothing to this guy. :)
I was thinking when I saw you hot air soldering, I made a foil shield with a rectangular hole for the IC I was after heating the legs on, last time I did some thing like that as not to melt adjacent components! That said my diagnostic skills and knowledge are zero compared to yours! Good to see you are still human 😛
I really believe you'd get 250,000 subscribers easily if you keep posting. The editing of your videos is probably more of a hassle than fixing the equipment but I really see you getting a significant group of followers. Extra cash flow is always nice as well! Would like to see you try again fixing that unreleased Bose that stumped you!
Hi Mark , good to see an excellent engineer at work . Just to say that I designed the main power PCBs . The front panel circuit was a successful legacy design and used on many of the other TTi PSUs . I am not on the TTi staff , rather an external designer . The company is very helpful if you ever require schematics etc .
The magamp affords a very easy method of synchronous post regulation . The control of the reset current is very simple , the switching is very soft thus not causing EMI and it is virtually indestructable . A semiconductor implementstion is considerably more complicated and no-where as robust . Over the last 30 years , I have used magamps in various different TTI designs putting the quantitiy of magamps out in the field in the hundreds of thouthands .
@@ekus6196 Interesting :) When I first came across the schematic I started looking for info about how magamps work - and just couldnt find anything much other than them being "historic" components!
I saw the thumbnail and witout reading the caption I knew it was the supply under the knife. I don't think any engineer can face doing a job until their own kit is fixed and back up in its rightful place.
I always enjoy watching your fixes. I'm a fixer myself, but with less experience in certain areas. I appreciate your attentiveness to diagnose the issue in an efficient manner. It keeps things in a watchable manner.
Hi Mark Just a small gift from one repair guy to another, I only started watching you a couple of weeks ago, Now I watch you all the time! I have a youtube channel but it has remained dormant for ages. Thanks for the great videos & the inspiration. Paul from Edmonton, UK
That setup procedure reminds me of CDC band printers around 1980, 12 25-turn resistors to get it set up, and nearly all of them mutually dependent, even the +5 and +2.5 rails. Oh, what fun we had.
Outstanding fix as usual. You have such a relaxed, deliberate and effective approach to troubleshooting. This is the South Main Auto version of electronics repair
I picked up a dead one of the exact same power supply that was being thrown out at work. Haven't confirmed the fault symptom yet but this has inspired me to open it up and have a look :)
great to see a uk repair channel ! love your optimism , if i see a pic micro i think bugger thats the end of that then! ive been haunted by pics suffering amnesia in arcam amps and tti psu,s keep up the good work , youd be a hero if you keep saying "esd protection ? dont need that nonsense here in the uk ! no one believes me, rain earths out esd
Hey Mark - thanks for saving me hundreds at a repair shop and hours of continued pure frustration. I am an avid watcher of your great videos. I had a problematic onkyo amp with a bad volume dial which has a servo. One channel kept cutting in and out when the volume dial was moved or sometimes dropped in and out at random. Not great. You showed how amp module cards can be just easily removed on some amps, so I just pulled out (unplugged) the volume card module unit and cleaned it (over cleaned it with contact spray :). Having said that now works 100% 📟. Cheers from Australia !!
Well, I have watched almost all your videos since finding you a short while ago. Besides having great videos, One thing that sticks out to me is, You seem to have everything (not hyperbole either) , tools/equipment/gadgets, even cast your own parts. I was amazed when you rebuilt a transformer. The more I watch the more you blow my mind with everything you have at hand for the repair. Amazing! Nice work Sir.
TY Mark for another great video! When you speak the langauge of Ohm's Law, everything just clicks into place! I am so envious of your work bench, all the test equipment and your understanding of the language! More importantly, I am envious of your ability to have a "clutter-free" work bench without 30-40 projects going on at one time awaiting parts! Well done sir!
The simple joys of fixing things. I have the newer version of the same PSU, so it is good to know what's in there. I use square gutter downpipe brackets to space my DMM off the top of the PSU. That's what happens when rack mount kit gets bench mounted on a budget. Great video.
Excellent video, showing all the steps to fix & calibrate the power supply. It does help that it is a dual output unit, making it possible to not only compare readings from side to side, but also verify the diagnosis by swapping components between channels. Well done, sir. Great video. Liked, subscribed.
Nice video again mark. Absolutely love these vlogs of yours. I've not been electronics engineer for some time 37 years to be exact. Bringing back good and bad😮 memories.cheers😊
I enjoyed this video so very much! I will have to keep coming back for more!! Thank you for sharing your talent and passion for what you do with us Mark.
I really enjoyed this one. Pleasantly surprised that it was just that one chip which needed changing and that PSU was spotless inside, looked brand new. Beautiful. Best tech repair channel on the web.
There are a lot of good repair channels on UA-cam but this one is one of the top 5. Your expertise is amazing. keep up the good work we really like it ;-)
Well done, Mark. I had no doubts you’d fix it, and thanks for the tips on the hot air chip exchange and air temperature. Useful to know. Catch you next time !
We have a few of these at work, and someone kept blowing them up! Turned out to be when one particular person was plugging in a load of PCB's that were going on overnight burn-in, they kept shoving the plug in backwards on one or more PCB's, which sent 12V @10A back to one of the other power supplies the wrong way, and frying the diode across the output terminals, there was a tell tale brown burn just between the output sockets! New diode and they would be back up and running in no time.
Great video mate. Learnt how I failed to repair a guitar pedal some years ago. Didnt know the correct process to fault find the chip. You made it look easy. Thanks 😅
So, what we also can learn from this is that multi-channel power supplies are excellent self-donors of parts and have built-in reference for when only one of the channels goes bad!
New subscriber here from Texas. Love your work/videos. I'm an avid viewer of Uncle Doug, Mr. Carlson's Lab and Northridge Fix channel's videos. Your channel is added to my Notifications. Keep up the great work. Thanx!
I've learned a lot of trouble-shooting steps watching Mark's channel. Mark's laughter is part of the appeal, so genuine and infectious. I'm really glad discovered this channel. PS - The test eq in Mark shoppe must have been 2x a small fortune !- some excellent kit in there for sure !
Wow those PSU are complicated I am going to tot up how much all your test gear will cost out of my league glad I am out of the trade now and dont have to use a microscope to repair things great job as usual Mark
Love your videos Mark. Don't know what it is! This was quite a lot more involved than I had imagined! And isn't it great to fix other peoples stuff and be able to fix your own when they break in the process? Fantastic!
Very logical and meticulous approach. great video for budding electronics engineers. I would confidently give my Vintages systems to Mark for repairs. unfortunately based in Bangalore, India
great to see you fixing the test equipment, surprised it was just the display measurement.. quality kit mind withe the comprehensive data and calibration.
I love watching his video. It's his personality and the way he does things that gets me interested. I get happy and laugh. He is the best guy on youtube. P.S. Have you seen the other technical repairmen on UA-cam, wow, they are dry and talk so much that I have to go to the toilet at least 3 times.
Nice work there Mark. Folk shouldn't be overly concerned if a PS is accurate 'only' to within 1%, and your variable PSU seems much batter than that; somewhere around 0.2%/0.1% ... wow that's good enough for anyone.
hope you'll be back to making videos soon.I've run out after watching them all.I've learnt soo much.thanks mark.look forward to your next video.10 out of 10 :)
Very enjoyable to watch. Thank you for making the time to film each step. I'm sure your time is valuable and it takes you at least 3 times as long to do the job on camera.
Who goes through the work of unsoldering a potentiometer beforehand to solder a chip, now you had double the work lol. I wouldn't have thought that adjusting (calibrating) the laboratory power supply would require such effort. The nice thing is that you are happy to have a functioning device again. LG
Kapton tape is your friend when using hot air to remove components. Looks like a high quality product! Looking around your lab I have test equipment envy...
Thank you very much for this video. I have the same power supply but branded Sorensen XPF 60-20. My unit is also out of calibration. So it looks like I now have what I need to calibrate it. I dont have the service manual yet, so I at least have two possible makes and models to look for. Thanks again, Subscribed ! P.s. You only really needed to transfer the good A-D to test your theory.
Hey Mark. I have a B&K 1550 bench supply I suspect got wacked by an inductive load. It's been sitting for years. I almost threw it away because I couldn't find a schematic for it. You inspired me, so today I dug into it and found a shorted FET that switches the output on and off. Replaced it with a similar part I had on hand, and it works perfectly. Love your show. Thank you!
72 year old ex repair guy from the 80,s . Only things I can add are use capton tape around before air gun desoldering and a drop of liquid flux on the pins to help desoldering . What amazes me most is your dogged patience . I would have thrown half the stuff out the window ........................... respect !
The attention to detail while filming is amazing. I can't imagine how many times you have to move between shots just to show a bolt being unscrewed. Excellent production value, guess you go 110% on everything you do. Congrats.
VVman. You are a gentleman and a scholar Just saying :)
I’d be dreading fooling with that chip and Mark is like whatever, let’s move em around for kicks. Dude is amazing. Love this channel.
I was thinking the same, I wondered how many cameras were in use and what sort of mount to get in behind the equipment on the bench.
I would have been scared to swap the chips as Mark does in the video using just hot air. Very gutsy repair.
if there were more people like you, the world would be a much better place. While i am interested in what you're doing, who you are as a person is why i keep coming back. All the best from Australia mate
Sliding it back onto the shelf, and the moment when you push it back and forth a few times just for the joy of hearing the rubber feet squeak... small things like that make life worth living. You are my favorite Internet technician with your deep and useful skill set, the cheerful and dogged determination with which you attack any problem, and your respect for vintage electronics... even a few things we recognized as 'cheaply made' back in the day. You shrug with every new challenge, fix it right, repair the hinges and recast the knobs. You give it your all which exceeds 150%.
Sir I have been a tech retired worked for 40 years. You are a natural. Very bright and the fastest I have seen at troubleshooting. You are still young I hope you get rich. W5DN
Nobody gets rich repairing hardware like this. It's a vocation.
Between the 25 quid for the replacement chip and the value of his time… well, it *might* be less expensive than buying a new one, it is after all a 1200W jobbie, but I wouldn’t put money on it.
It's amazing to think that Mark's skills include the knowledge to diagnose and repair his own test equipment. Warranties on electronics mean nothing to this guy. :)
Well done Mark. Excellent diagnostic skills! Handy to have lab equipment to help you check your lab equipment 🙂
I was thinking when I saw you hot air soldering, I made a foil shield with a rectangular hole for the IC I was after heating the legs on, last time I did some thing like that as not to melt adjacent components! That said my diagnostic skills and knowledge are zero compared to yours! Good to see you are still human 😛
I really believe you'd get 250,000 subscribers easily if you keep posting. The editing of your videos is probably more of a hassle than fixing the equipment but I really see you getting a significant group of followers. Extra cash flow is always nice as well!
Would like to see you try again fixing that unreleased Bose that stumped you!
Hi Mark , good to see an excellent engineer at work . Just to say that I designed the main power PCBs . The front panel circuit was a successful legacy design and used on many of the other TTi PSUs . I am not on the TTi staff , rather an external designer . The company is very helpful if you ever require schematics etc .
@ekus6196 out of interest, why was a magamp chosen for the design? It's not something you see very often!
The magamp affords a very easy method of synchronous post regulation . The control of the reset current is very simple , the switching is very soft thus not causing EMI and it is virtually indestructable . A semiconductor implementstion is considerably more complicated and no-where as robust . Over the last 30 years , I have used magamps in various different TTI designs putting the quantitiy of magamps out in the field in the hundreds of thouthands .
@@ekus6196 Interesting :) When I first came across the schematic I started looking for info about how magamps work - and just couldnt find anything much other than them being "historic" components!
Of course now I've searched again, I've found a paper at TI called "Magnetic Amplifier Control for Simple Low-cost Secondary Regulation" :)
I love this guy. His happy face shows how much he loves his job.
This is one of the best things to watch on the telly.
That power supply is actually a really nice piece of equipment; dual 1200 watt channels 60x20…definitely worth the effort to fix that. Nice unit
It had better be nice, and worth repairing, since they go for about $1500.
I saw the thumbnail and witout reading the caption I knew it was the supply under the knife. I don't think any engineer can face doing a job until their own kit is fixed and back up in its rightful place.
hell yeah! was hoping this would get a follow up.
you are by far one of my favorite repair channels on here. keep it up
I always enjoy watching your fixes. I'm a fixer myself, but with less experience in certain areas. I appreciate your attentiveness to diagnose the issue in an efficient manner. It keeps things in a watchable manner.
Hi Mark Just a small gift from one repair guy to another, I only started watching you a couple of weeks ago, Now I watch you all the time! I have a youtube channel but it has remained dormant for ages. Thanks for the great videos & the inspiration.
Paul from Edmonton, UK
Hi Paul, I just found this in the comments! Thankyou very much! A bit late, I know... Mark
Yes! A new video from Mark, just in time for some nighttime relaxation. Thank you Mark. 👍
That setup procedure reminds me of CDC band printers around 1980, 12 25-turn resistors to get it set up, and nearly all of them mutually dependent, even the +5 and +2.5 rails. Oh, what fun we had.
Outstanding fix as usual. You have such a relaxed, deliberate and effective approach to troubleshooting. This is the South Main Auto version of electronics repair
My 'go to' is PHAD, got to clean those green crusties!
Great to see you upload! I can't wait to see how you fixed the decapitated rocking horse.
Very satisfying watching you mend test equipment, nice one Mark
I picked up a dead one of the exact same power supply that was being thrown out at work. Haven't confirmed the fault symptom yet but this has inspired me to open it up and have a look :)
They say the dumbest people are the happiest. To be as smart as Mark and still have a smile and attitude like that, he must be truly happy.
great to see a uk repair channel ! love your optimism , if i see a pic micro i think bugger thats the end of that then! ive been haunted by pics suffering amnesia in arcam amps and tti psu,s keep up the good work , youd be a hero if you keep saying "esd protection ? dont need that nonsense here in the uk ! no one believes me, rain earths out esd
Wonderful electronics repair channel. Good thing you have other Lab testing equipment to re-calibrate the repaired dual power supply.
I have to say I admire your confidence and skill. If I had tried to swap chips I would have two knackered channels and probably a few broken tracks.
Me too.
I would have waited for the new chip to arrive having confirmed that was the faulty part
Hey Mark - thanks for saving me hundreds at a repair shop and hours of continued pure frustration. I am an avid watcher of your great videos. I had a problematic onkyo amp with a bad volume dial which has a servo. One channel kept cutting in and out when the volume dial was moved or sometimes dropped in and out at random. Not great. You showed how amp module cards can be just easily removed on some amps, so I just pulled out (unplugged) the volume card module unit and cleaned it (over cleaned it with contact spray :). Having said that now works 100% 📟. Cheers from Australia !!
The attention to detail while filming is amazing.
I wish mark was in south Essex. We have a lot in common. Such good videos and a fabulous man cave workshop
Casually changes several SMD ICs. I love it Mark, you’re a hero!
Well, I have watched almost all your videos since finding you a short while ago. Besides having great videos, One thing that sticks out to me is, You seem to have everything (not hyperbole either) , tools/equipment/gadgets, even cast your own parts. I was amazed when you rebuilt a transformer. The more I watch the more you blow my mind with everything you have at hand for the repair. Amazing! Nice work Sir.
I love the fact you don't give up
Excellent discipline and knowledge
Good show for everyone
Mark....i held my breath....metal screwdriver tip! how about a plastic pot adjuster? great channel
Watched all your videos Mark. I am now watching them all again. Fascinating stuff. I'm hooked.
Nothing is more satisfying than having your own tools work.
Good job , Mark 😎😎👍👍
Man truly knows his stuff absolute pleasure to watch thank you Mark
I never cease to be absolutely amazed by your incredible skill, knowledge and talent Mark.
I watched you break it so I had to come and see what the problem was. Again, nice work. 👍
Mark. Another exceptional view, many thanks , pls keep them coming!! Your channel, is immense . Pure inspiration and joy!! Wonderment ⚡️⚡️
Awesome as Always... Great Update Loved this.
amazing tool the TTI, I have two myself someone was throwing away! They're smaller and much older but amazing! Great video I enjoyed the cal process!
TY Mark for another great video! When you speak the langauge of Ohm's Law, everything just clicks into place! I am so envious of your work bench, all the test equipment and your understanding of the language! More importantly, I am envious of your ability to have a "clutter-free" work bench without 30-40 projects going on at one time awaiting parts! Well done sir!
The simple joys of fixing things.
I have the newer version of the same PSU, so it is good to know what's in there.
I use square gutter downpipe brackets to space my DMM off the top of the PSU. That's what happens when rack mount kit gets bench mounted on a budget.
Great video.
Excellent video, showing all the steps to fix & calibrate the power supply. It does help that it is a dual output unit, making it possible to not only compare readings from side to side, but also verify the diagnosis by swapping components between channels.
Well done, sir. Great video.
Liked, subscribed.
When I see your smiling face at the preview, I know. Will be fun. Good job Mark!
Superb content and video quality- in awe of your microsurgery skills!
Nice video again mark. Absolutely love these vlogs of yours. I've not been electronics engineer for some time 37 years to be exact. Bringing back good and bad😮 memories.cheers😊
Excellent video, thank you Mark.
hi mark watching in new zealand just love watching your videos
Great job, very nice power supply , high-quality electronics
I enjoyed this video so very much! I will have to keep coming back for more!! Thank you for sharing your talent and passion for what you do with us Mark.
I really enjoyed this one. Pleasantly surprised that it was just that one chip which needed changing and that PSU was spotless inside, looked brand new. Beautiful. Best tech repair channel on the web.
Super.Szanuję ludzi z pasją.A do tego taką, jaką sam posiadam.
Uwielbiam elektronikę audio, zwłaszcza tą z duszą.Pozdrawiam z Polski.
There are a lot of good repair channels on UA-cam but this one is one of the top 5. Your expertise is amazing. keep up the good work we really like it ;-)
Great to see you again Mark thanks for sharing 🦘
I really enjoy this channel... not just electronics, but machining and general restoration too! I've binge watched every video. Keep them coming Mark!
Well done, Mark. I had no doubts you’d fix it, and thanks for the tips on the hot air chip exchange and air temperature. Useful to know. Catch you next time !
We have a few of these at work, and someone kept blowing them up! Turned out to be when one particular person was plugging in a load of PCB's that were going on overnight burn-in, they kept shoving the plug in backwards on one or more PCB's, which sent 12V @10A back to one of the other power supplies the wrong way, and frying the diode across the output terminals, there was a tell tale brown burn just between the output sockets! New diode and they would be back up and running in no time.
Your channel is going to grow huge in time Mark, amazing content.
Very nice diagnostic tips and great videography as usual Mark. Thank you
Great video mate. Learnt how I failed to repair a guitar pedal some years ago. Didnt know the correct process to fault find the chip. You made it look easy. Thanks 😅
Hello from across the pond. Love you channel, your setup and knowledge is OUTSTANDING. Thank you for sharing
It’s always a joy to see you’ve posted a new video Mark, thank you.
Hi Mark! Love you're channel, Can you please do a tour of you're workshop and how some things work? That would be great! 👍 Anyone else like that?
So, what we also can learn from this is that multi-channel power supplies are excellent self-donors of parts and have built-in reference for when only one of the channels goes bad!
New subscriber here from Texas. Love your work/videos. I'm an avid viewer of Uncle Doug, Mr. Carlson's Lab and Northridge Fix channel's videos. Your channel is added to my Notifications. Keep up the great work. Thanx!
I've learned a lot of trouble-shooting steps watching Mark's channel.
Mark's laughter is part of the appeal, so genuine and infectious.
I'm really glad discovered this channel.
PS - The test eq in Mark shoppe must have been 2x a small fortune !- some excellent kit in there for sure !
Wow those PSU are complicated I am going to tot up how much all your test gear will cost out of my league glad I am out of the trade now and dont have to use a microscope to repair things great job as usual Mark
Love your videos Mark. Don't know what it is! This was quite a lot more involved than I had imagined! And isn't it great to fix other peoples stuff and be able to fix your own when they break in the process? Fantastic!
Mark, I always learn something new from watching your videos. Thanks 🙏
Very logical and meticulous approach. great video for budding electronics engineers. I would confidently give my Vintages systems to Mark for repairs. unfortunately based in Bangalore, India
Best electronic repair channel also have so much smile too lol
Always a pleasure watching your videos. That load device is a thing of beauty!
What an incredible channel. Love your enthusiasm in the videos.
Congratulations! You are an excellent technician! You pay a lot of attention to every detail! But also in the quality of the videos! Good job!
I really love your energy and positive attitude 😊
Thank you Mark, another beautiful video.
great to see you fixing the test equipment, surprised it was just the display measurement.. quality kit mind withe the comprehensive data and calibration.
I love watching his video. It's his personality and the way he does things that gets me interested. I get happy and laugh. He is the best guy on youtube. P.S. Have you seen the other technical repairmen on UA-cam, wow, they are dry and talk so much that I have to go to the toilet at least 3 times.
Nice work there Mark. Folk shouldn't be overly concerned if a PS is accurate 'only' to within 1%, and your variable PSU seems much batter than that; somewhere around 0.2%/0.1% ... wow that's good enough for anyone.
Good Power Supply, I had an issue with mine and the same chip, letting it stay turned off for a day fixed it.
hope you'll be back to making videos soon.I've run out after watching them all.I've learnt soo much.thanks mark.look forward to your next video.10 out of 10 :)
Very enjoyable to watch. Thank you for making the time to film each step. I'm sure your time is valuable and it takes you at least 3 times as long to do the job on camera.
Oh no your bench power supply broke - good thing you're mend it Mark! No problem.
Time to grab a cuppa and watch
At 11:36 I shouted at the screen that the chip was round the wrong way, at 11:39 it was correctly orientated, so you heard me then.
You have some great kit there.
Who goes through the work of unsoldering a potentiometer beforehand to solder a chip, now you had double the work lol.
I wouldn't have thought that adjusting (calibrating) the laboratory power supply would require such effort.
The nice thing is that you are happy to have a functioning device again.
LG
Kapton tape is your friend when using hot air to remove components. Looks like a high quality product! Looking around your lab I have test equipment envy...
Thank you very much for this video.
I have the same power supply but branded Sorensen XPF 60-20. My unit is also out of calibration. So it looks like I now have what I need to calibrate it. I dont have the service manual yet, so I at least have two possible makes and models to look for.
Thanks again, Subscribed !
P.s. You only really needed to transfer the good A-D to test your theory.
Thanks for the video and the insight into your repairs. Great footage and editing by the way 👍
Great video. I really like TTI kit, normally very high quality.
very enjoyable repair much learning Merry christmas Happy Newyear for 2024
Very thorough, reminds me of my test/fault finding and calibration days. You're getting me back into repairs again lol
Friend, great maintenance and calibration class.
Every time I see you I remember Star Trek actor Brent Spiner (date)
That unit is $1500! Wow great save Mark 🤠
old tool its very accurate, I remember my oscilloscope in 1999 at electronic school laboratory.
Thanks Mark, You are a master technician