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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!!!!

The best and easiest explanation I’ve seen, Thankyou

Thank you very much.

Why is every patchbay tutorial video about mics preamps compressors and never about straightforward synth and fx!

Great !!!

I like that you literally explain what the difference is of each channel was and where that that break comes into I didn't really fully understand the admit her the bass and The Collector and what the percentage of them actually working is until you fed me this information I think you would be an excellent teacher for anyone

Great examples! Great video

Very thorough!

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.

That was possibly the best explanation of the workings of a transisteor and an amplifier I've ever seen in my 5 decades.

A proper visual aid. Well done

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

Yo gumpe grow a pair then you can comment until then pipe down. Go take your moped for a ride.

is it really a big job to fix the choke mechanism itself? Like, if one thinks the choke might not be openeing up all the way.

Excellent video. I wired 96 way normalised times 7 bays many years ago, I remember all that soldering lol

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.

sleeper vid on cable creation and interfacing. i haven't built any audio cables yet but i'm 2/2 on 30A power cables. sounds like a great project! thanks!

About to try this on the speaker for my bass amp. I'll let you know if it worked

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

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

It may have already been stated, but be aware that 1/4 TRS cables do not allow 48 volt phantom power to pass through, so you can't use phantom from the preamp to the mic over a TRS to XLR cable.

I just got your video feed, I just finished watching it. The best explanation I seen about output transistors. I finished troubleshooting my vintage Sony amp, two bad outputs. Great job.

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.

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.

awesome work! Great idea with the epoxy. I will try to use epoxy as a base to get the p-tex to stick to my edge core shot.

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.

Actually - a great explanation. Thank you!

This video was very appreciated! Thanks!

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.

아주 훌륭한 설명이었어요. Great video ! Well explained. Should be very helpful to me.

Thank you I really enjoyed thus video👍. Lol now to see if it helps me

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!

Videos are awesome bra! I grew up cliff diving too! Gangster 👍🏼 patchbay videos saved my life. You’re a pro

AWESOME 👍🏼

this is the best explanation on you tube. thanks

I like your video it's giving me some good ideas on patch bays thank you for doing this video

The casing of the output transistor is collector. The other two pins are base and emitter.

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

One of the best explanations! Well done, thank you.

What is the name of that epoxy product?

Thank you!

I 100% echo the comment immediately below. You perfectly explained where to check and WHY the resistances varied from 23 ohms down to the 1.2 and 0.7 ohm levels. Showing the resistor values from the schematic and linking those to the resistances that you measured was gold. Thank you for sharing and explaining in such detail!!

good vid, may have saved me lots of time cheers bravo

Phase Linear was famous for the same issue

do you know if this works with coaxial speakers?

Is the out/in swapped on the rear panel? Like the output coming FROM the microphone is feeding INTO the top on the back side, making it technically the input? In the case of the norm/hnorm are you getting the OUTPUT of the connected mic from the bottom and feeding that cable into the preamp input? (still from rear of patchbay?)

This video inspired me… …to just buy a patchbay

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 ?

Now I finally understand lol.Great video!