LUXMAN Preamplifier Repair - The LUXKIT A3300 Preamp

[@MrCarlsonsLab]

To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab

[@jasonthejawman5442]

Your repair video educational

[@nyckhampson792]

Mr Carlson, no idea where to start other than I like your teachings , makes my 85-89 Physics, electronics teachings coupled with tech drawing to shame at Deyes High School, Maghull ,Liverpool.,Merseyside ,L316DE (post code / zip code Canada )England. Anyway , I'm in Republic of Ireland ,South Coast , my two kids also 11, and 13 , both gamers , however we like basic electronics .... Any advice , moreso for me tbh Why the F didn't they teach or even now teach like you do ? Ooops I know why , keep us down 👇 Mr Nicholas Hampson N

[@talents010]

This video really showcases Mr. Carlson's attention to detail. One of (if not the) most knowledgeable electronics guru's on KZbin.

[@markianclark9645]

Talents...well..he has a couple of rivals for that honour...over here in Britain near Birmingham...we have MenditMark channel...he has about as many diagnostic machines as Mr Carlson...and knows how to use them too...also an ex pat from here now lives in Canary Islands and has a channel Learn Electronics and is a teacher to subscribers...not quite as many diagnostics but it's quality over quantity as they say

[@fotoralf]

Paul "Sherlock" Carlson practising post-mortem criminalistics and inspecting fingerprints inside a power supply. 🙂 Most entertaining and thanks for showing us.

[@carolynhilliard4903]

Hi, I'm a 5 year old electrician, and I've been watching your videos with my mom and dad. I love them. My favorite part is watching you take apart components. I think it's funny when you call capacitors 'caps.' Please make more videos with your homemade leakage tester.

[@JCWise-sf9ww]

Really liked your repair work on this stereo preamp. Good job explaining the circuit and what parts was needing replaced. Thank you Mr Carlson.

[@MrCarlsonsLab]

You are welcome!

[@jaydeebishop2345]

You are responsible for my interest in electronics. Thanks for having turned your house in a movie set and allowing me the best seat for the show. Asking the right questions is the better part of learning. I appreciate the drive you bring in my experience. Cheers

[@johnparichuk8367]

I've been using a curve tracer since the early 1970s during my Navy career. Back then, it was just the basic components cobbled together, driven by an audio generator and displayed on an oscilloscope via the X and Y axes. One of the best tools available.

[@stephensams709]

Yeah, they used to call them an octopus, if memory serves me right. I later used a Huntron Tracker and it was very useful as well.

[@stevenedington6265]

Yes I was introduced to the curve tracer in the Navy in the 70s we called it the octopus. It was a staple on my bench until I retired a few years ago.

[@stevenedington6265]

The company I work for PTS electronics also made one to be attached to your o scope.

[@kevinhamming4514]

Ive never used a curve tracer. If a transistor is bad an ohmeter will reveal it . I suppose its good for trouble shooting, which I dont do much of. Is this usefull with the transistor in the circuit? In that case not having to take the transistor out to check it helps.

[@stevenedington6265]

@@kevinhamming4514 The curve tracer can be used when components are in circuit. I get better results with them out. The curve tracer will show you leaky diodes and transistors that an ohm meter won’t. It will also show a leaky electrolytic cap.

[@rsc4peace971]

I have been following your content for over 4 years. I am never disappointed with the level of detail you go through to not only explain the basics but also the meticulous way you troubleshoot and rectify (yes pun intended here) the big and small problems. You go above and beyond to even uncover mistakes in factory manuals. This one is even more interesting where you casually opened the PS to discover potential deal breakers if left to itself. Your passion for what you do is just out of the charts and your desire to share this with the masses is so beneficial to both casual enthusiasts but even some pros who do not take the trouble explaining what, why or how they fix things

[@RobertBelt-x6d]

Agree... I found Mr. Carlson's lab several years ago because I had no idea what & how a capacitor worked. I since have followed his videos for my learning and have over time taken lot's of notes. I often refer his channel to others that I come across on a couple of vintage radio Face Book pages I follow.

[@_m_ev1673]

To the beginning, a general comment about Mr. Carlsson's Lab videos: Excellent English and with excellent articulation. The vast majority of KZbin video creators should learn from this. I am not a native English speaker and I can understand Mr. Carlsson's speech perfectly. The same applies to speech parsing. Consistent and clearly progressive. A real talent!

[@billysharp3388]

I like watching you do repairs, you make it look so easy and enjoyable.

[@mkepler5861]

and yet, another great video!!! thanks Paul for showing us some more of your knowledge and skill!!! mike

[@frankpitochelli6786]

You sir are a brilliant technician, I wish I were your neighbor. I was a TV tech for 40 yrs.... Love your skills, I would be at your lab everyday..😅.. Best wishes Paul.

[@luminaetsonos4169]

As Always, Paul is not just creating video to watch, but teaches techniques, tips, what to "keep in mind", fine repairmanship and bonus incident investigation. you are a ballerina of electronics :P. Thanks a lot and keep it up, more power.

[@FelixGarcia-x3i]

Just got into antique radios. Your videos have been amazingly helpful. Thank you

[@MrCarlsonsLab]

Great to hear!

[@NullReference119]

As a long time viewer I've long since realized you're carefully selecting what you think would be the most educational for each video. That said I'm surprised you didn't express regret that whomever destroyed those screws didn't use a proper set of JIS screwdrivers which would have prevented that. It's important to remember that any gear from Japan will use JIS spec screws and that standard Phillips bits will cam out and strip those.

[@jlog7395]

Great video highlighting a great preamp. Really appreciate your schematic walkthrough and troubleshooting explanation. One thing I’d like to see you spend a few minutes comparing specs of the new transistors to find suitable replacements. Also, what you look for to decide if the bias resistors need to change for the new transistors. Thanks again for your great videos - I’m learning so much!

[@J0HN01DATA]

Critique a capacitor is an art. Great repair and debug to what seemingly would be root cause, I bet it was. Very fine line between a capacitor and a 'crapacitor'. Thank you for sharing!!

[@johnmarchington3146]

Thanks, Paul, for another fascinating video. You are an amazing person with your attention to detail. I could hardly believe it when I saw those wires trapped under the transformer bracket. How anyone could fail to see that is beyond me. All it needed was a quick check before refitting the cover and the person would see them. The sine waves looked nice and clean after you replaced all the transistors and they were obviously pretty well matched too.

[@jmasseys]

Hi Paul, I liked your choice of beginning and ending shots. Nice change from your wide shot of your bench. Oh, and your content, as always, was very informative. Cheers, Scott

[@joewharton-vy7oq]

i see the algorithms are favouring you, just a little thank you, as i was recovering from a stroke just before covid lockdown, i always seemed to by directed back to your ft-1000mp repair you gave me the idea to reactivate my ham licence M1DLS......... . the tinkering and shack fittings also helped with the recovery, i now own a ft-1000mp and a few others, my latest obsession, is to sync forgotten radio's i:e ic-735-- ft-840 with sdr software giving the old girls a face lift...... ham's dub it as a pan adapter anyway i'm rambling, thanks for the nudge, love the equipment you use lol

[@PeterEdin]

The other problem with cameras is colour balance, I've had red wires appearing pink, but there were also pink wires present as well. That lead to a "paracetamol event". 😆 This channel is the best 😊

[@hnatyshyn]

It's been a while I watched your channel. Forgot how interesting and instructive it was. And often the treat is to learn about the repair stories of the devices, like in this video. And meanwhile, I bought myself the Hakko desoldering gun. It's like a dream. Thanks for the lessons

[@mp-ov9dh]

great video,! I have jumped full in to this old tube stuff, amps and radios test gear. The depth of your videos is second to none and you have taught me so much about this dying art. I i have 1 patreon account and its your content. consider me a huge fan and thanks!

[@MrCarlsonsLab]

Thanks for your kind feedback!

[@ericfox507]

Excellent as always! Greatly appreciate seeing the mix of vacuum tube and solid state based electronics. Thank you.

[@mikefinn2101]

Another great informative video. Still waiting for the follow up on the old BC348 receivers. You very detailed and I learn so much just watching you. Thanks for the additional info on matching transistors and the freq sweep. Glad you explained that.

[@leetucker9938]

Mr C's analysis / inspection was awesome . Decoding the hidden past of the unit

[@Electronicsmusicisme]

Yesssssssssss. Hands down, the best KZbin channel. I really appreciate the effort you put into this channel

[@Rendon276]

Quality video and audio. Very articulate. KZbinrs should learn from your example.

[@MrCarlsonsLab]

I appreciate that!

[@DonaldRichards-mr3lz]

I am 61 years old I have been a student of electricity most of my life ( 3 or perhaps 2 years old ) and I have to say you have a very good work place there I have a small work / computer station a pc type Hantek scope , DMM I hope some day I will have a real Lab work station .

[@cafemolido5459]

Mr. Carlson, it's kinda therapeutic to watch your videos. Easy going, speak clearly and slowly and in simple terms

[@martinda7446]

I've come across this problem a few times over the last 40 years, it was very common to use the power amplifier to feed the preamp via an umbilical that often terminated in an octal connector. Issues were usually because someone had broken the keying peg off or the umbilical connections had become fractured with repeated movement and connections... Never had any other problems as far as I remember, nobody managed to shove/force the connector in the wrong place, and its usual to fiddle about to find the key, but unless there is another problem the connections do not make until the connector has mated with the key. But after 60 years they can look a right wobbly frayed mess! Worth checking his cable for issues. I would before I let him blow up my work on his headphone amp. Edit: then you mentioned it.

[@leonardpeters3266]

Great stuff. You can say it was "just a repair", but really it was an excellent rebuild of the headphone amp and a nice analysis of the original issue. Nice work very enjoyable. I am getting allot better at the SMD work, trying it for the first time on your Ultra Probe. On a parts hold for the amp/demodulator but the circuit board is ready. It will go in a cabinet with speakers built in. Getting excited about it.

[@joenovak6393]

Thank You for another Learning/Educational video. I am now a Patreon supporter ($10), and I look forward to your projects and videos. I am a Luxman Fan boy with a number of 70's Tube and SS gear.

[@MrCarlsonsLab]

Welcome aboard!

[@brucejenner5856]

How can we not enjoy your videos??? I'd just came home from work, put water on for me bath, put telly on, there I saw a new episode! Glass of rum and coke, and I'm in for a treat.

[@jaakkolehto1487]

Still think you and shango066 are the best channels on youtube. Commented that 5 years ago but still the best.

[@MrCarlsonsLab]

Thanks for your kind comment!

[@amitanaudiophile]

You are very rare restoration expert on earth❤❤❤

[@LeftieLouie]

Very nice work! We could benefit from your reasoning regarding replacement transistor selection.

[@saintmichael2931]

Another fantastic video for learning! The audio and video quality is EXCELLENT as is the verbal commentary made every step of the way through the repair. Looking forward to the next adventure!

[@larrybud]

12:30 I've definitely had an "oh crap" moment when I was trying to rewire stuff after taking a picture, and I couldn't tell where a particular wire actually terminated!

[@johnh5896]

Fantastic work the best job ever calm thoroughly intelligent easy to understand and meticulous precision to watch is like watching a master class in electronics bravo Mr Carlson 🎉

[@BigEightiesNewWave]

The classic 70s look outside, my favorite to this day, but with tubes inside, nice.

[@terrym1065]

Another great repair as always Mr C..👍👍 In depth explanations of circuit analysis with schematics are always a bonus in your content, thanks for that. Beautiful piece of equipment, glad it was reparable without major stress and the power supply surprises, well...wow! Thanks for the video and work, much appreciated. See you next time. 73

[@michaelcarey]

Excellent video Paul! One possible reason for the chewed out heads on the case screws of the power supply could be the use of Philips screwdrivers on a JIS head. This equipment being Japanese... I would hedge my bet that the fasteners used would be JIS. While it is common to see the tell-tale dot stamped in the head of a JIS fastener, it's not always the case. I did training at the JRC factory in Mitaka in the early 90s and was instructed that Philips screwdrivers are NOT to be used on JIS screws as they will cause damage.

[@Betterhifi]

Wow! Great job on the headphone board! I was shocked at the previous tech tightening down the transformer of the wires!

[@charlessmyth]

It's good to be able to clearly read the resistor colour codes :-)

[@kristyskirt9015]

Lucky who ever did lousy work did not get a Leathal Shock. Very nice work Mr. Carlson I lke your snazzy solder sucker you use and the tracer nice Carlson design. Thanks for Always warning everyone about The Danger of the elevated High voltage in Tube equipment.. Cheers

[@dougtaylor7724]

Mr Carlson could make tons of money on daily tour and a bed and breakfast. For $500 a night you get to met Mr Carlson, sit for a one on one white board design session, eat lunch, watch a video taping, tour the Mr Carlson personal equipment hoard and a ride in the bucket truck. Where do I put my credit card info?

[@Runco990]

The ride in the bucket truck sold me!

[@lolilollolilol7773]

He probably makes more just by doing repairs and it's less fuss lol

[@wellingtonalvesbomfim]

Thank you very much, my friend, we are from the same professional field, I am a naval technologist, in the radio field

[@toddtonis]

Thanks for the great explanation during this video of what you're doing. I learn alot watching them. Also, excellent video work showing the circuit details; very high quality.

[@johnny-z]

Nice! I love high end audio. MORE please!

[@markd.nightingale4266]

Beautiful well done and thorough presentation. Easy to younderstand and follow along. Thank you!

[@MrCarlsonsLab]

You're very welcome!

[@outthereassociates7155]

Nice change-up Paul. Always enjoyable no matter what you're working on.

[@nudebaboon4874]

Thanks for passing on your endless knowledge Paul!

[@MrCarlsonsLab]

My pleasure!

[@jessiec4128]

This was a very good video. I am learning as I watch your videos. I Love watching your videos. I was watching your videos a long long time ago. And it came up after a long time. Now I am back to watching more and more.

[@KeritechElectronics]

Ha! Back with the curve tracer action :). I built mine and use it sometimes - and I'm glad to you for the ideas! That was indeed a bunch of baaaaaaaaaadly discombobulated transistors. Nice investigation of the possible root cause.

[@user-uz1yv2oc9v]

I worked in Japan from 1985-1994 and towards the end of my contract I used to see so much faulty Luxman and Sony ES gear for pennies in the recycle stores, I was always so tempted just to fill a crate with the stuff and ship it back home but it never came to fruition. Visited a few years ago to go snowboarding and couldn't help have a spy in a junk store and they still had some luxman gear but it was top dollar now :( Nice attention to detail though on the repair of this amp and for reminding me of days gone by

[@allenjamesrooney]

I worked in a TV repair shop for 16 years, starting in 1971. One day one of the guy's routinely pulled the back off a TV set, and found a flashlight inside. It had Japanese writing on it. We all assumed that somewhere in the manufacturing process an inspector accidentally left it inside the set.

[@hughmc5419]

Nice rebuild of headphone board. I like the repurposed O'scope for trouble shooting.....

[@Skibidi_Male_X]

Respect !!! Bob Ross of electronics repair.

[@glennk1931]

Fascinating as always. Always enjoy your amazing knowledge on these projects.

[@MrCarlsonsLab]

Glad you enjoyed it

[@PatrickSilvestri-cg7bq]

You always keep us amped up very good Mr. Carlson. Love your videos.

[@dougg1075]

Luxman is definitely one of my dream jams.

[@pauleichenberger4966]

Thank you Paul, for another great video tutorial! Your test bench equipment is amazing. Looking forward to the next one. Cheers, Paul.

[@MrCarlsonsLab]

Glad you enjoyed it!

[@Greg-et2dp]

Mr Carlsons lab you are good at restoring antique radios and alignment of antique radios and restoring antique tvs and amplifiers and am fm stereo receivers

[@nathanbrassington7659]

Of course your here, beep boop!

[@apostlewoody]

I dont understand any of this. But I watch every EEFin video. I love it!!!

[@5argetech56]

I remember on the Price is Right '80's they would have Luxman component stereo systems on the show. Sheer cream of the crop!

[@juliohormilla3862]

Great detailed video as always, one idea that occurred to me is if a diode was added in line on the preamp side on the 8.5 volt from the pin to the board, if the pin with negative 80 volt came in contact with the +8v pin again it would probably save the board.

[@petercarroll684]

Hi Mr Carlson would you be able to cover everything you look for when replacing components to know what would be a suitable replacement thanks for the video really enjoyed it as always and keep up the good work

[@billrr02]

I have no idea what you're saying, and I'm not sure why, but I love your videos. Also, you have the best mic / audio setup on KZbin! Well done, sir!

[@RonHicks]

You're very thorough Mr. Carlson.

[@fkaMilo]

I learned a lot from that. The process of logic and observation

[@davido.hamilton3254]

Thanx Paul. I always enjoy your attention to detail.

[@MrCarlsonsLab]

My pleasure!

[@99thDimension]

After 25+ years of buying & paying for repairs to vintage gear I've had enough pro gear has gotten reasonably affordable and specs out better then older gear I spend more $$$ buying/repairing vintage gear then the cost of new gear. I have two Heathkit Power Amplifiers AA-1506 in for a complete rebuild mainly because I built the bi-amp open baffle speakers system to match them these will be the last of the vintage gear for me.

[@davelowets]

I like Luxman equipment. I have a Luxman TP-117 Receiver/Preamp from the late 80s, and it STILL sounds VERY nice when compared to modern Hi-Fi stuff.

[@faxcapper]

Paul that was SO interesting. I have Luxman solid state integrated Amp.

[@Geoduck.]

That was interesting thank you Mr. Carlson. Luxman makes some great sounding audio gear.

[@clintonwalker5000]

I love to learn electronics mr Carlson you’re the man 👏👏👏💪

[@alexispieltin9379]

Nice and very interesting video about those japanese components. A classic issue with these 100V supplied units is many are tempted to check if any primary winding is available for "international" conversion and other primary voltages. But hence specifically described and checked, it's rarely the case. And it could explain some bad manipulation with some direct short from primary or B+ and all these tampering with screws and wiring. Some should definitely tell to those collectors to be really suspicious about every Japanese material. They're easy to find on the net, but difficult to use if you don't have the adequate rare down voltage transformer (here in Europe with a primary 230V AC supply, it's unobtainable over a certain power limit!). And as you could expect with any tube material, the exotic and never the same B+ is even more difficult to source.

[@eDoc2020]

At least your 230v supplies usually have a different socket type. The plugs on 100v equipment are the same as our regular 120v plugs so it's easy to apply the wrong voltage without thinking.

[@martinvanek5951]

Love your videos. I'm currently building a Nelson Pass Class A amplifier (His Burning Camp design sold by DIY Audio). Next I'm going to tackle re-capping my 40 year old Hafler DH-110 preamp which has no line output although the headphone out appears OK. Cheers KN4MNA

[@harbselectronicslab3551]

Your new camera angles and shots are awesome….. great stuff

[@AudioNaut93]

I’m a young(ish) 30 year old avionics technician that works for American Airlines and my true passion is stereo gear but it goes further than just listening to music. I want to know the differences between solid state Vs tubes, class A vs class A/B, class D etc etc and how to work on them when they fail. I’m not even joking when I say I’d sign up for an apprenticeship with you in a heartbeat to really learn this stuff and I wouldn’t expect or accept any payment but knowledge. This is truly fascinating stuff here.

[@KiloKhanMax]

21:52 love the q-tip board scrubbing ASMR

[@arsimahmetaj6272]

The Electronic king is back in the house “Mr Carlson “

[@ElectronicMechanic50]

Man i love my hakko desolder gun same as you have it make repairs so much quicker!

[@4X6GP]

One additional thing to check: I would have opened that octal plug that goes into the power supply. There could be a stray strand of wire that might have shorted between the 8v and the filament line. Having said that, chances are that what happened is exactly what you described. The "technician" probably heard a pop, but then the preamp's main output continued to work, so he thought he'd dodged the bullet.

[@resipsaloquitur13]

I dont know anything about anything.. The symetry they put in that small board. I can 100% appreciate that. That means whoever designed that cared about it. At least a little.

[@davidcottee2808]

Great video & repair. I was surprised that the pilot light didn't blow if there was an over voltage to the preamp as it comes off that supply. Or maybe it did, and was replaced before coming to your workshop.

[@garyiyi]

Very professional . I really hope you are live near my place.

[@Gary-wb8qt]

This 76-year old male says your Luxman video reminds me of the Dynaco Pat-4 stereo preampifer and 60-watt Southwestern Technical Products, (Motorola?) stereo amplifier I had in the early 70's.

[@macsledge3225]

Thanks again for another informative and well produced video. Was wondering if you could explain in a future video how you go about deciding on suitable replacement transistors in audio equipment. Cheers.

[@tweedeldee8122]

We need to clone your brain Mr. Carlson. AI can't hold a candle to your knowledge.

[@dougtaylor7724]

AI has not reached this amount of intelligence yet.

[@DarrenSteele-mx3ks]

@@dougtaylor7724 LOL!

[@awakenedtotruth8419]

If I may add, you have a radio voice that can easily zen us throughout a troubleshooting process.

[@awakenedtotruth8419]

​@dougtaylor7724 That's done purposely to not take over the military where most A.I. is utilized.

[@shawnbottom4769]

The concept of actively troubleshooting electronics has nothing whatsoever to do with AI but it can help you understand how a circuit works.

[@graemebrumfitt6668]

Rite Paul, Very nicely laid out, have to start calling you Sherlock Carlson, nice bit of detective work on the ps! TFS, GB :)

[@ellisc.foleyjr9778]

Another great Video Paul. I"lm well beyond the need to do anything anymore. not a "paid bench tech. just an average Amateur Radio op for 60=yrs. made my fair shareof smoke on projects. and at 80 yrs old I can still learn things what ? for? who know I might getthe doldering iron out again before I croak. Oh! thermal bit on the diodes had an old timer (back when I was 20) toldme abut that one nice tip thanks for sharing. ECF

[@Satchmoeddie]

I bypassed the safety cover interlock on my Tektronix 567 curve tracer, and I have blown up more than my fair share of T092 sized transistors, and those hot & fast flying little pieces REALLY do HURT a lot! The switch & teat on that safety cover got wonky, so I bypassed it all. I get lazy with the T092s and often don't put that cover on. I have launched TO-3 and TO-66 tops out of other equipment, and boy am I glad that cover is on the 576 to catch those. That is like playing "bullets in the camp fire". The bullets stay behind because they are a lot heavier than the casings but the brass casings pop off with lots of energy.

[@gilbus4989]

Another excellent electronics tutorial. Thank you

[@robharley9838]

Great video as usual Paul! Just wanted to put in a request for a session with a class "D" amplifier, so common in modern popular gear these days. They seem to be a different beast. Your insights into their design and operation would be very informative no doubt. Also, wanted to let you know that I purchased a UNI-T 8803E bench DMM a while back and all I can say is "WOW!". Thank you for that recommendation and all the great content you share with us! - jrh

[@UKDrew]

Awesome as Always... Thank you for such cool content.Pleasure to watch and learn

[@clintonwalker5000]

One could definitely trust you for repairs 💪👌

[@sjaakvansoest9210]

Great video Paul many thanks!!

[@x5-acousticguitarstuff.2]

I own a Luxman L-550X Integrated Amplifier and I love it.

[@rle43]

Interesting and informative, as always, thanks Paul.

[@MrCarlsonsLab]

My pleasure!