Simple fix for a blown audio power amplifier - Save your $$$!

[@alexbradley2186]

Don’t even talk yourself down about how this is boring....I came here because I needed some help and you did a better job than any other video I’ve watched and I appreciate your time for that, this video is older but I never needed anything like this until now, but this was easily one of the best transistor-fix videos out there, very, very clear and I learned quite a bit from your video. Thank you

[@SZINNAPALM]

Funny thats basicly what i just told him to right now i didnt see your re$ponse till after but i clicked the like button on your reply as well as the main video

[@donaldcatlett5850]

👍

[@Sajanmohan1]

Well said!

[@MrRadbadger]

Hear hear👍

[@riverboat28]

Fuck the haters!

[@romariogrey7271]

This is one of the best video to simplify a audio amp out transistor thanks a lot u couldn't have made it any easier thanks again all thumbs up love the video

[@Marie579]

Boy You Rock !!!!! you're naturally informative and clear in your explanation and i agree with the other comments you should be teaching.

[@St.E.V.T]

Absolutely great video.. you are a natural teacher and excellent at explaining stuff. Thankyou so much .. please make more.. ill bet you’d be really popular if you had a repair channel on here..excellent stuff! Not long not boring always moving forward in a way that makes sense. The transistor explanation was excellent and building from there was very informative .. thx again

[@Come2Lord]

I am working on an old amplifier, and this is the best information I have found to trouble shoot a dead channel...

[@johnbobbitt6470]

Just FYI, that’s not a “1” on the multi-meter. It’s an “L”. Some meters will say “OL” which stands for “out of limits”. Means the resistance is outside the limits you’ve chosen to test because the two probes aren’t actually being connected through anything - cuz the fuse is blown. If a connection is made between the two probes THROUGH the fuse it will show the value of resistance in the object that’s being used to bridge them together. Good video.

[@nickloss2377]

it's a 1 on his meter. his meter doesn't display letters.. only numbers. But 1 on his meter means the same as 'OL' on your meter. not all meters are made the same.. different displays..some are alphanumeric, but the he's using is numeric. it displays and communicates the same information though, so he was reading it correct. 1 shows there is resistance. good fuses will show continuity..just like he said. sometimes I don't understand why people feel the need to "correct" things that are not wrong..

[@mr.e695]

DUDE!!! Thank you!! I sincerely appreciate your time. I've been trying an hour per day for FIVE months now to figure out how to fix my Pops amp. He passed a couple years back and this thing is pretty much all I have that lets me feel like we're still hangin' together and jammin' ... then it croaked about 6 months ago ... well at least one channel did. I knew it was one of the damned little transistor thingys after watching so many vid's and reading so much, but this was the FIRST one that I actually understood what those 3 stupid leg thingys do and why and how to work forward or back to find the other crap they screwed up along the way, so I can FINALLY rock out with Pops again ... well in spirit anyways ... and ashes too, a bit of em anyways I put in a glass thingy I glued to the top of the sub so he can still dance to the "tight bass response" of his Onkyo he always talked about, whatever the hell that means. I just know it sounds killer when it's working right, and I think I can finally feel comfortable about digging into this little F***er that's been my nemesis for months now. So dear Sir, again, please know that my gratitude is limitless at the moment for you and your valuable time that you've freely shared here .. I truly and deeply appreciate you and your efforts along with your ability to explain it so even an idiot artist completely ignorant of any technical knowledge and skills like myself could understand. It clicked ... and I bet dimes to donuts I kick this things arse now, I just know it!! Thank you SIr!!! ✌️

[@kezzytech6998]

Nope mot long and boring. You had me interested. Am normally rushing and skipping videos but some how you got me to watch the whole thing,dammmmm how you did that😭🤧

[@robpeters5204]

I loved this video!!! I watched it right to the end and I learned a lot. I am a newbie at this field but dabbled with it a long time ago. I have the same amp, it's great a real work horse. You are a really good teacher and I hope to see more of your videos. You have a knack of explaining things that keep me and hopefully others focused to the job. Thanks again and take care.

[@shanephillips4069]

Dude, I am extremely thankful that you put this video together!! I have a similar issue but I have just started down this long and dark path that lead me down to a rabbit hole I couldn't help but dive into! I have a board that keeps blowing a fuse on a bass amp that I don't have any of those round guys that you were showing I have these square ones that are on an aluminum plate and I want to say that they're bridge transistors, but I am not sure but there is solder missing on a couple of the points and I wanna say that is the problem. But I'm just not sure.

[@LostInAce]

Wasn't boring at all. I made very good use of it and replaced power transistors on an old, but solid built power amp. So, thank you for sharing.

[@arvindgoudar1586]

The way you explained how a transistor amplifies a signal was spot on. Thanks for this video, you are a natural teacher ..😊

[@MichaelBeeny]

I think the first thing I would do before any thing else is to blow out all the dust and dirt. Quite often overheating is the issue leading to blown transistors. Air flow is very important if the amplifier is driven hard. Once fixed any air filters should be well cleaned, check the fan, apply a little oil if needed. If you don't do this, it will probably blow up again.

[@TeDubbs]

You're absolutely right. I wound up going back in and blowing it out after I replaced the transistor. This one blew after it melted a 1/4" instrument cable which was connected instead of a proper speaker cable, but I doubt the excessive dust helped things.

[@donaldcatlett5850]

Won't hurt to clean it!💯

[@nickloss2377]

​@@donaldcatlett5850that's what he said.

[@timothywalters3760]

Thx lt Help Alot l Have A Cs 800x And lm Almost Sure Now That, l Believe That's My lssue And To Think l Tuned ln Fix my Cb Linear. THX AGAIN Bigg Help!!

[@dermotgilmartin1818]

Thanks dude i have a line 6 75watt 112 with no power at all now i found one power circuit board that by looking at it seems fecked so i needed to understand how to test everything else , before i buy parts, ☘ maybe let you know how i get on and thanks for this one 😎☘🙏

[@evenmorefunTV]

You measured the Emitter and Base. Your Collector-Emitter idea is correct, but this time you got lucky with your diagnosis.

[@kennyvanh]

Some folks are just good at breaking down complicated thing so others can understand them, it’s a gift 👍🏻👍🏻

[@SleepyFishing]

I am very impressed with your skill at teaching something that you yourself had only just learned. We the audience were clueless that you were new at this until you admitted it. Thank you for taking the time to make such a great and helpful video covering a subject that you have obviously discovered that is rarely broached yet needed to be covered.

[@TeDubbs]

Sleepy Dragonfly's Fishing Adventures Glad it helped

[@gabefernandes356]

That was the best explanation of a transistor I've ever heard! I've been learning about this stuff for several years and never felt I understood transistors as well as I do now. You've earned a sub for that alone

[@50sKid]

pretty great video, bro. appreciate it.

[@marcdich9066]

Yeah I will tell you also that if you have an amplifier that is that dirty on the inside you may just want to strip it down and clean it because it’ll do a lot better in the long run than just replacing an outlet transistor

[@johncotter8434]

Just watched one video on fixing broken amps which was useless and longer, then I came here and found what I needed to understand. Thanks a lot. I've been quoted $500 to fix my amp. I could buy a new car for that.

[@gonzodetroitify]

Where you think you talking alot, and making no sense, you've just helped someone who listen alot to music but couldn't tell you why something has blown, and now I'm using TOUR knowledge you've shared to go and tackle a crown xti amp, that starts up then shuts down!!! So THANK YOU

[@Synthematix]

If you dont find all the bad blown parts in an amp, they will all blow again

[@reyzuna]

N Gauge England -Synthematix- basically if a blown resistor and transistor are replaced, then your problem is done, You can’t mess around with other components specially if it still power on just fine

[@KritanSepersad]

Hi, I am very grateful for your video. You may not realise, but you have given some very important information about how things work which are missing in other electronic repair videos. As a hobbyist, I have learnt a lot from you. Thank you.

[@mdzacharias]

The two pins for each transistor on the underneath side of the board are the emitter and base connections. Guaranteed. You can still have an emitter collector short and the E-B junction might look OK and fool you with this test. One probe should touch the top metal body (collector) to test for the emitter-collector short.

[@JoeJ-8282]

Mark Z; Yes, you are definitely correct about that! The exact transistors that the amp in this video are using are the typical older style TO-3 metal case packages, and for regular silicon bipolar transistors of this type, (and exactly these part numbers, as seen on the schematic diagram shown, I looked them up in a semiconductor cross reference book I have just to be sure), they have the case itself as the collector, one pin on the bottom is the base, and the other pin on the bottom is the emitter. His test in this case still worked for him because the bad transistors apparently were also shorted between the base and emitter, affecting the readings in the way he showed, however he should have been testing them like you said first. And another thing I have issue with in his test method is using the lowest ohm setting on his meter for this test... Some smaller, less robust, lower power transistors can be damaged by your meter itself if it isn't a high enough of impedance and the meter sends too much current through mainly the base junction, which is more delicate than the other leads of the transistor... That is more of a problem with Mosfets and the "gate" lead, but bi-polars can also sometimes be damaged through the base lead by measuring with too low of an impedance meter... I would have used at least the 2K ohm range on that meter instead of the 200 ohm setting at the very least, and even better yet, use the diode check function to safely test for effective/good junction voltage drop. (A shorted silicon transistor will indicate 0.0V in both directions through a junction that is damaged, and ~0.55-0.6V or so through a good junction one way and open circuit the other way around, (switching the leads around polarity-wise), for each good junction.

[@mdzacharias]

Nice to see a reply from a "real" technician. Too many posers on KZbin. However, a base -emitter junction of a transistor could not be damaged by this (crappy) digital meter. It does not produce the voltage or current (even on the 200 ohm range) to do that; it's limited to about 1 milli-amp tops. Even less likely on a MOSFET. Static electricity would be a more likely potential problem. Lots of old analog meters can produce lots of current, though - I've seen over 150 mA from some with shorted leads on Rx1.

[@JoeJ-8282]

True. I was talking more about the old analog meters. I had no idea what the (admittedly crappy, "Harbor Freight special") meter in this video put out when testing in that way though, so especially with cheap or unknown meters like that I'd start in a higher range with less current output... Better safe than sorry if you don't know for sure... I don't really have to worry about that though, because I always use one of my 3 Fluke meters for testing stuff. I have an older 87, a 189 and a newer 289 model Fluke, so I think I'm good!... I gotta get me an oscilloscope though! I've never been able to afford a good one, and they're very hard to find used too... Maybe I just don't know where to look for one. :(

[@mdzacharias]

For audio, maybe look for a B&K 1472 (working with a trace shown) on eBay. They're often under 50.00 plus freight. Very good for audio because they go to TWENTY volts per division. I'm a Fluke nut myself. Wearing a Fluke T-shirt right now in fact. Couldn't tell how many Flukes I own without some head scratching. Let's see. Three original 87's, an 85III, an 87III, 87V, 8840A, 77, re-branded Fluke 23 (Square D brand), a Fluke 12, a 27FM, and a couple "parts cars". That's about it, I think...

[@mdzacharias]

BTW the BK 1472 is only 20mHz. All you need unless you are working with FM front ends...

[@NNITRED]

Exlnt video mate, This a great primer for understanding transistors and looking for something other than a blown cap.

[@fins59]

Very good and clear explanation of how a transistor works and how to diagnose a bad output transistor.

[@robertholsopple9451]

Hello, im new to this but im interested in it and have repaired a few things here and there but should someone replace transistors in sets from the same batch? I heard that before I repaired one of my Kenwood km209 amps so I replaced all 4 from the same batch. The argument was that the gain wouldnt be the same on mixed batches or mixed brands of transistors. Only 1 was actually bad. But i replaced them all because i wasnt sure. Does doing that have any benefits? What are your thoughts on that? Thanks. Good video BTW.

[@TeDubbs]

You bring up a good point & several other people have mentioned this issue since I made the video. According to some online resources, unmatched transistors can cause issues as you say in certain circuits since the gain will vary. Truthfully, I am neither qualified nor knowledgeable enough to know if this is true & in what cases. I may have gotten lucky and bought transistors that matched the existing ones, but my amp is still going strong!

[@alexgreen121]

Thank you, excellent video I really enjoyed it.

[@jkylek5661]

bro thank you, you give the best explanation i have found thus far in understanding how this stuff works and why. please continue the awesome work. again, i thank you and appreciate your hard work.

[@daleswezene2076]

Driving a speaker load with a guitar cable is always s bad idea. Good clarity on your explanation of tracing out the faulty output transistor. Did you know that dust becomes conductive after heat and current flow hit a trigger point? That sends the DC rail voltage where it should never go...avalanche voltage breakdown followed by shorted output devices. Clean away the dust and check the mica wafer for cracks. Replace the wafer if it looks compromised.

[@lyyliesther3219]

Thanks Most well explained (in simple terms) video I came across so far on this topic.

[@simplisticperspective344]

Easy to understand straight to the point great vid

[@steveellington7413]

Thanks for a very quick and simple explanation. Easy to understand and very helpful!

[@chuckgilly]

You did good, I understand more now then I did before, you explained it very well in layman terms, thank you for your time.

[@samuelcajeles85]

Thank you for your effort...A word of caution though, replacing the defective output transistor without checking its forward bias whether it's within limits or not will allow the audio amp to function again but for more or less 15 minutes only because the transistor will overheat and be defective again.

[@megalodonscortex7578]

I have a bp7004 Definitive technology. The capacitor in it got replaced and upgraded. I put it back together now the power light won’t turn on. I take out and plug it back with power. I hear a little hum from it. I called support from Definitive technology they will replace both amps for $200. I’m paying for something that will have same problem down the road later. I got loud humming coming from the amp made want to fix to begin. Please help.

[@megalodonscortex7578]

$200 to replace it to get same problem later is not worth it. That is why I replace the capacitor and upgraded them.

[@gjb6177]

You helped me fix my Sansui 881 and saved me hours! Thank you!

[@christopherfogarty8142]

Thanks for posting this! Before I watched this, I’d never considered pulling a bad transistor and the amp will still work, albeit with less power output than before, but the point is, it’ll still work! I tried it on a vintage BGW amp I have with a blown channel, and transistors made of unobtainium, and it worked! I removed the same transistor from the opposite side, even though it was good, so both channels would have equal output, and Shazam! An amp that hadn’t worked in 20 years was back in service! THANKS again!😉😎👍🏻

[@reyzuna]

christopher fogarty lols if you’re just pulling out transistor that is fine but if you have a bad one it will not work basically if you pull the bad transistor it may work just like what you did

[@BrewerShettles]

Great Video. Thanks!!!

[@anthonyibrahim643]

Thanks for a great and informative video. Extremely helpful information that was very clearly explained.

[@jdrs4214]

Brother, you brought back memories of my High School Electronics classes, and you're probably better at electronics than I am. Ill tell you one thing tho. You refreshed my memory on the transistor and resistor topics. So thank you for taking the time to make this.

[@truthteller1475]

Thanks brother. I knew nothing about this circuit diagram but now I understand something new. Thanks for teaching me.

[@BoHunter2010]

Thanks for your work and the time you put into the repair and making a quality video. Just curious if the amp worked after and if it is still working today? Where did you find your schematic?

[@TeDubbs]

The amp has been working great running a practice PA setup since I fixed it 3 yrs ago. Glad I could help!

[@standyer8120]

Great video thank you for sharing. All the hours you put in to learn this has saved other people countless hours researching themselves.

[@JustinCrediblename]

thanks, man. I bought a mackie m1400i on ebay and it's not outputting sound. There's definitely sound coming out of the EQ (hooked headphones directly into it, adjusted volume and worked properly) The lights on the m1400i work properly. There's a quiet popping noise coming out of the machine every second or so. It makes a small noise through the speaker when I flick the power button on. The LED "cold" (which indicates good temperature) comes on, and the LED on the power switch turns on. The interior fan is not on, though. I dunno if it's supposed to only turn on when the unit gets hot, but doubt it. Could this be a blown transistor, or will the unit be 100% non-functional when there is a blown transistor? There is no fuse or circuit breaker panel that I can see on the unit, front or back. (edit: but I haven't opened up the case yet)

[@StreetLifePromotions]

Awesome vid .. I have a QSC PL9 and one of the channels stop working. I was about to bring it for service and like you already know, it is an outdated AMP which would cost me $$$$$ then who to tell, similar issues can resurface again ... knowledge is POWER. Thank you for such detailed vid for DIY like myself ... you just saved me $$$$$$$ for now :)

[@kenm.6502]

Hey thanks for the video, it was very informative. I was wondering though, on the second set of transistors you found that only one read low, and the attached resistor was bad. Am I correct in assuming that the resistor was reading open line? And because it was open line it isolated the bad transistor, removing it from the circuit? Thank you for your time and keep making videos!!!!

[@jasoncheek]

Thanks for the video hopefully I can repair one of my QSC900's this way. My question is odd I have access to another 4 or more of these for free, my work bought an old theater to demo and gut out. I'm running these in mono bridge mode to an 8ohm 3200w single sub. Since they're identical models, in theory could I stack/strap a pair with a split signal coming in, and run 2 amps to one sub? Or stack and run #1 as a master parallel and #2 as a slave? It still wouldn't exceed the limit of the sub anywhere close. Just wonder if I could easily double the bass hit since I have access to a stack of free QSC900's.

[@betchbetchington6019]

Hey thanks! This video was actually super helpful. I've been wanting to get into fixing electronics for a while so I went and got myself a gig fixing amplifiers and speakers for a local pawn shop today. I have no clue what I am doing and I like the way you explain things and it wasn't boring at all!

[@trenenpierskalla5500]

I’m sure you get lots of questions from people but I’d appreciate any suggestions from you. I have an old Crate B10 xl solid state amp that I’ve been trying to get working again for a couple years. There isn’t any repair places near me and I searched all over online with no luck finding any similar problems like mine. I was playing it and all of a sudden zero audio, not even a hum, the fuse wasn’t blown and it still powers on. I’ve confirmed that the speaker is still good, I can’t see any signs of something that got hot or blew, the jack inputs are making contact and all of the wiring is good, none of the caps look bulged and it doesn’t even make a sound when I touch the aux jack. I’m suspecting it’s a component on the circuit board but I can’t see a visible problems, I’ve tried testing everything with the knowledge I have, it makes a small sound whenever I touch two of the pins on the output transistor/mosfet so It might be that but I’m not sure. It might even be one of the many diodes.

[@davidbanwell7728]

Wow thank you you explained that very well I've now fixed four of my blown amps cheers buddy. 👍🍺

[@brandonroskom5890]

how did you acquire you wiring schematic????? i have an amp i am testing, but can't find the schematic online.... any insight would be greatly appreciated. great video, thank you!

[@RorisangMdluli]

I have a Rock Sonic Amplifier so I checked it and found 2 busted ACs I repaired them, then 2 days of good sound the equaliser screen starts flicking as if there is not enough power 4 it to remain stable. Now when I play Audio it goes like play pause play pause. I don't know what to do anymore because I even fixed all 2 fuses.

[@twoblink]

My fuse blew; and I put new ones in and they blew right away as well. So I'm trying to hunt down the culprit. Can I test them from the top? I can't easily access them from the bottom..

[@peterfrench209]

Great video... Audiohead ah700 channel B... Not working. Sir, I have an Audiohead AH700 with channel B not working... Its not worth sending for repair as I can replace it cheaply.... I have taken readings from Transistors as follows. Toshiba C5198 C to E and B to E readings at 200 ohms 1. 1.0 and 14.8 2. 0.4 and 14.7 3. 0.9 and 14.8 Toshiba A1941 C to E and B to E readings at 200 ohms 1. 0.9 and 16.6 2. 0.4 and 16.5 3. 0.9 and 16.4 Is transistor 2 in each set faulty?

[@PeterHammett-ie9ws]

Excellent Video ! Like you I have searched hours to try and find enough info to try and track down faulty components in an Amp. Most of the ones I have found assume that you are already something of an electronics expert, so don't give such a good and detailed explaination as you have here. Can't praise you enough, but my thanks.

[@seanmcguire6998]

Stumbled upon this video - GOOD JOB! One thing I can suggest - along with working one-handed, use a wooden dowel or chopstick to poke around bitey electronics. A drumstick works as well, until your kid steals it. :D

[@rcary]

Hi. I picked up 3 amps, McGregor SA series. 240x250 i think used for PA system. Fairy basic and big components inside. All 3 have a nasty constant buzz on the channels. Doesnt matter if i turn up or down the volume. Sort of sounds like a loud transformer buzz, but coming from the speaker. Im fairly competent with soldering and whatnot, so where do you think the problem is hiding out?? Caps? Transistors? Cheers from Wales.

[@Rick_Erickson]

I can't imagine this has not been pointed out yet but the solder pads on the board connect to the Base and Emitter. The Collector is the big metal case on the other side. On this model QSC amp the collectors are grounded directly to the aluminum heatsink. Most amps isolate the collector with an insulator, some of which require thermal transfer compound, others do not. It is also quite common for other components to short (or open) along with the power transistors. While I understand that you are trying to help people out and save them money, you are in effect giving them just enough information to possibly do serious damage to their amp or to themselves in the process. It isn't always as easy as it looks folks.

[@PeterHammett-ie9ws]

Excellent video ! Like you i've done a lot of searching to get enough info to track down faulty component(s)i in an Amp. Most of the ones I have found assume that you are already something of an electronics expert, so don't give as good an explaination as you have here. Can't praise you enough.

[@riverboat28]

If you're not an idiot you should be fine.... Has anyone checked who's president in America lately? 😂

[@raydunne71]

Do you have any other info on amp problems. I don't think mine is completely blown nor that the issue is an ouput transistor. I have no circuit breaker that is user resettable and my internal fuse is intact. The amp powers on but it doesn't provide the driver with what it's meant to do. The power light blinks when there is a power spike such as a bass hit and the driver will attempt to produce sound but there's a clicking sound coming from the amp and any sound that the speaker produces is scratchy and once in a while it will almost make a clear sound but it just doesn't quite make it. It's a built in single channel amp for a JBL self powered subwoofer model Sub 12 from the 2000s era Venue series. Not a great sub but not bad either and I have a full set of speakers from the series. The Sub 10 works fine on the system so it's not an issue with my AVR.

[@moisesvazquez2018]

if it's not the resister not the trans sister what would be the best option to check on?

[@giorgostexnikos6976]

amazing video.

[@tomterrif8503]

Thanks for the explanations, but for future videos PLEASE stop waving the fuse/screwdriver/meter/pen around! GAH!

[@johannjohann6523]

Yeah great video. I like to collect stereo gear, find stuff at garage sales and such. And often you can find something inexpensive, but does have a small problem. Or your cat can knock over a cup of water onto your turned on beloved amplifier and well you know. So I'm getting into learning how to fix the equipment instead of tossing into a land fill. Especially my beloved amplifier/AV receiver which was quite good, and would be expensive to replace with a new amplifier/receiver of the same quality today. Like $1,000 or more.

[@silverfoxxsound6768]

With the Crown C 2000 can I bridge just by plugging inWith the Crown C 2000 can I bridge just by plugging in Elo for connected

[@wlue1]

Thanks, I learned something and I haven’t seen any showing this before, something I wanted to understand for a while now. So, kudos!

[@LongStep]

Where can you get schematics? I can't find the schematics for my Proton D1200.

[@MrTopsoil911]

Never touch any component with a screwdriver eventho its unplugged! Caps hold a charge. Also u should clean out the amp as u will benefit with better air flow circulation. U already have the cover off so why not!! Exp elect tech here 36+yrs in the business

[@anthonyhosford4282]

Hey thanks for sharing. Once you have some knowledge of repairs this would be helpful. Talking about help, does anyone have a gemini xga 3000 service diagram? Even though the Amp was new there wasn't any in the box. Thanking in advance for any assistance. (I switched on Amp and cap just blew up. No short circuit🤔)

[@resynthesizer4565]

Thanks for the video. I've arrived at the same conclusion, and it's nice to see my logic was correct. Where I'm at now, however, is why did the transistor blow ? Was it just old ? Overheated ? Shorted speaker wires ? Before I go putting in new transistors, I may want to answer this question if I can. Great video, though. And again, thanks.

[@revoxjazz8317]

I have a probably identical situation with a Dynacord amplifier and I will try to examine it according to your explanation of this. Thank you very much.

[@kevinkoons5901]

Hello, I watched your video on repairing a power amp. I have a 2 channel QSC power amp that 1 channel is distorted like it is clipping. Any thoughts on what this might be? At first I thought I had a bad driver in my speaker but after changing the cables around to the other speaker i realized it was the power amp itself. Any thoughts would be appreciated.

[@nissanhardbody697]

Great vid. !!! Catching up with some projects at home while at quarantine. Got an Old QSC amp most likely from early 90s that has bad channel, no sound. Thinking Speaker cable got pinched, cut, shorted while playing at a small get together bout 200+ party people. Just wondering what website you recommend to get schematics for home or car amplifiers in general???

[@emperorofgroove]

Man this is the way I wanna be taught!! By a guy who learned it himself and can explain it in simple language. This was great. Pretty sure thats what I got going on here. Not sure Im gonna do it myself yet. Not the best with a solder gun But I really wanna learn this stuff and your explanation was great. Just like everybody else said great job.

[@mmgerecke]

This is great info. I am wondering if you can offer a bit of advice. I have a power amp where one channel has an extremely harsh buzz, not like a ground loop hum, but like when you touch the subwoofer cable end... loud, harsh buzzing. Could this be a transistor/resistor issue or should I be inspecting elsewhere? The other 4 channels do not buzz at all, just the one. I have not opened to inspect fuses. If a fuse is blown, would I get any sound from the channel? Thanks!

[@johncoscia5258]

Irriresistable output transistors shorted out in a bank in the left or right channel , easy for you to explain very well and find. But this overload and smelly components bbq can be caused by not a short but an open circuit in one channel speaker loose banana plug which overdrives the other to go into protection mode ? One side of one channel open circuit loose banana can cook your Denon amp ?

[@gfernandez9285]

Hopefully u can help me...My tv surround sound system powers on, but speakers and base box not working, no sound from anything. Everything still has power, just no sound. Nothing has changed in 3 years it has been working and all of a sudden the sound just went out. I think it could be a fuse, but idk if it would still be powering on. I did every other simple troubleshoot, restarting, changing socket, unplugging all wires and back in. Only thing that's left is a fuse in the back I didn't change yet. Basically could set still be powering on if it's a blown fuse???

[@StagnantMizu]

Not sure if u said it in the video but this is a good FIX and if you want an upgrade on >20Y/O amps you can replace all the capacitors with newer beter ones for better sound

[@MrDizzyfinger]

Excellent video , thnx man. I have a Harman Kardon HK 6600 amp blowing fuses { 2 out of 4 } at power up .I will certainly check the output transistors. Cheers :)

[@Rezonances]

What if you had high DC voltage on one output of a Class D amp? Someone connected another amp's speaker outputs to this powered monitor's speaker out (it's a Kanto powered monitor pair). He didn't play the other amp that loudly. Now all we hear is some slight buzzing on the good channel, and then there's 26.55v DC on the other output, but no music plays through the good channel. I wonder if these Chinese Class D amps have any real protection at all... no fuses were blown all, but that makes some sense because the powered monitors weren't in normal operation. Seeing such a high DC output makes me think a coupling cap isn't working, but then this video makes me wonder if it's a transistor or 2 or even more hmm... The big problem is that there aren't service manuals for a lot of new Chinese gear.

[@revoxjazz8317]

Definitely, the explanation here on the issue of replacing power transistors will be the best I have ever seen, including some aspects that may be less clear to most people not trained in this activity.

[@ragman5099]

Your video was not boring I jus wish I could understand it better you explained everything perfectly iv jus always had problems understanding electronics I wish you live around me I need help with my Boston Acoustic Sub I don't know for sure but I think my amp plate went out on it

[@doubts72]

Hello can you help me diagnose my Denon Av Receiver ? My son was playing video games and all of a sudden there’s a loud clacking noise coming from the surround speakers when there’s a loud scene like cars racing there clackle and goes away at lower volumes . I tried another set of speakers with higher watts and it still does it, so I’m sure it’s not that the speakers are blown . Am I screwed here ? I can send you a video to your email ? Please help . I’ve looked on you tube but none seem to have the issue like mine .

[@caseykittel]

thanks. big help. I am just collecting info for a repair I will be doing soon. one channel is NG. I didn't mind you carrying on at all. good info. also I set the playback at 2x speed. fun.

[@eksine]

that's the dirtiest amp I ever saw, but good job explaining this man, appreciate it!

[@wulfclaw4921]

"If you're not an idiot you should be fine". Heheheheheheh. Priceless ! Thanks for the tips, man ! Wulfy

[@vintageyamahabackyardresto4995]

How did you know that the resistance was going to be 23 ohm? It doesn't look as if it says that on the schematic. Did you find the information somewhere else? Great video and explanation btw. I have a Hartke HA5500 that pops fuses when you turn it on and I did a little reading and people say a common issue is the output transistor or the output transformer. I downloaded a schematic, but was wondering if you found the resistance value on a forum? Took the 23 ohm value from the working channel, or was there something on the schematic that showed you? Thanks in advance.

[@dadabaimusic]

At least I learnt something from it, thank you and greatly appreciated for your video (01/11/2022)

[@brandonjoesephwysocki4320]

So here is my issue im getting full dc to speaker output , but as you said so much garbage online i cant figure out what im testing exactly or what to check. I did use multimeter on out put shortly and a huge spark but never figured out from where. It fries the speakers pretty quickly if you have an idea please let me know !!!

[@CarlDidur]

Good vid. I have watched many. I am a service tech working mostly on tape machines and I just avoid these haha. I won't have to in the future

[@pablorodriguez3595]

Dude. You definitely did not make a fool out of yourself. Your explanation put me on the right path for me trying to fix my reciever. It is not the same but it works the same. Thank you very much. You rock!

[@kelzagoodman]

very good accurate basic description. nice. -- the last part that analyzes the circuit is very good

[@davidkim9217]

That was an excellent video and a fantastic explanation. I have instrumentation background and an electronics degree. I also own a DJ company and have always sent the amps back to manufacturer to be repaired due to time constraints. i have so many amplifiers that need replaced that i am going to fix them myself. This was a great quick troubleshooting video. Well Done!!!!

[@SLUMBERWELLYOUTUBE]

hey man i've got an amplifier in a portable PA, [Harbinger M350] i think its malfunctioning but just on one side (Right) and also I have confirmed my fuse is not blown. My right side speaker won't play back and yet it still gets a red light reading. I don't know specifically it could be. any recommendations ?

[@sj460162]

My amp has a standby light but no display or click when I rurn it on?? HELP!!!!

[@EdiNaumov]

Mine has every transistor pointing 23.3 when testing them, but i have no sound coming out fron channel 1 any idea what it could be?