Guitarists...DO NOT BUY THIS JUNK! - Vox Micro Amp Repair EPIC FAIL!
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- เผยแพร่เมื่อ 1 ต.ค. 2024
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This video is a comedy of errors. It documents an utterly failed attempt to repair a Vox MV50 Clean micro amp with a Korg 6P1 NuTube in the preamp. Although the NuTube was not the failure, I get the sneaking suspicion that this is a cheesy, gimmicky attempt to wrestle more dollars from guitar tone seekers who would be far better off simply buying something more traditional (AND SERVICEABLE) with a 12AX7 in the preamp. The output stage contains a Texas Instruments TPA3118, which is a 60W Class D amplifier in a 32-pin surface mounted IC about the size of my pinky nail! Replacing it will take incredible patience and a steady hand - neither of which I possess. The fact that Vox / Korg will NOT support their products by supplying a schematic for servicing means this thing becomes another piece of E-waste garbage in the landfill when it breaks. My advice is DO NOT BUY anything with this surface mounted SMD garbage unless you just like throwing money away, especially if the company that made it will not support their product.
www.nutube.us/
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Brad, Use lots of FLUX and NO solder paste. Clean the area with braid using plenty of flux. Tin one corner pin and place the chip on top. Use your soldering IRON to solder that leg to the tinned pad. Do the same at the opposite corner. Now add solder to the first pin and move down the chip with your iron. The solder will run down the chip. If you have plenty of flux the solder will only stick to the pads and legs. Repeat on the other side. If you bridge any legs just clean your tip and touch the pins, clean and repeat. That is not a difficult IC when you have practiced.
That thing wasn’t made to be repaired. It was made to be replaced.
Nothing is ever made to be repaired. It's a skill that you acquire based on learning how things work.
This is damn easy to work with if you were to know what you're doing, nothing here is too tiny to hand solder, and there is no need for a microscope, this is not Rossmann level of tiny shit. The IC is still mostly or even completely in working condition, enough to tell what is wrong without even lifting it. The device has got a shutdown tick, so you go through latched FAULTZ conditions in the datasheet and eliminate them, simple as that, or see what else could be pulling the SDZ. Only after you have eliminated the possible external faults, can you replace the chip, or you'll just toast one more chip.
You mean like an Apple or many a Mesa Amp? Awesome!
@@SianaGearz Sure Brad could have traced down the circuit and debug the entire power amp section. But you forget one little thing: Brad is running a business, and a client will not pay a tech more than this amp worth to get it fixed. The fact that Korg does not supply a schematic makes it unservicable. Repairable yes, if you are some bored electronics tech stuck at home quarantine looking for something to mess about with.
@Matt Fields That's what Korg says, but they're assholes about that, too. So my takeaway is, instead of an inexpensive purchase, think of this as a very pricey rental. No thanks. I'll stick to my clunky old tube amps--that I know how to service, and are still running after 50 years.
It was made to be smashed with a hammer!
To those who suggested this paste contained solder, you are probably right. My bad! This is very far from what I ordered. I ordered clear flux, in a syringe. If anyone has a suggestion on what might be the issue with this amp. I might give it one more attempt when the right flux paste arrives. The winning answer (if I’m able to determine it) will receive a free code to download the Song app. Thanks to everyone for any and all tips. SMD is obviously pretty new to me, so I’m a fish out of water here.
It sounds like it's going into thermal shutdown. I'd check the output filter portion of the circuit, being a class D amp, you should see an LC filter somewhere in there between the IC and the speaker output. Check out the TI datasheet and look at the application circuit. There are a handful of caps that can short to ground in there, might be a good place to start.
Hi brad have you tried to clean all the jack and switches with contact cleaner, and you could also verify if it could be a faulty transistor. I woulld try to clean the pcb board too with contact cleaner. Good luck
JP
I'm so sorry, I laughed so much watching this. You sounded just like I would doing this except I'd probably doing a lot more swearing and I'd be using a hammer instead of a soldering iron :D
NO...I have not a clue whats wrong with that amp.....that's why I watch your videos..haha But, I am commenting because of your comment in the video about Google pissing you off for the last time....and that you decided to use ..Duckduckgo as a search engine. That my friend was "FLIPPING" AWESOME..!!! Because, I myself use Duckduckgo...bwa hahahahahaa Also, I use...Brave..!!! KUDOS to you my Friend..!!! Love your Videos...keep it up..!!!
When you get that syringe of flux, try using a dab the next time you reflow some crusty old solder when you are repairing something old. It wakes up that crumbly old solder and makes it slick and shiny like new.
Brad, you were SO CLOSE!!! I wish I could have talked to you at the 51:00 mark before you re-assembled and applied power. Those "bubbles" between the IC pins are SOLDER BALLS...they are the solder in the solder paste and they formed many short circuits between the pins of that IC. Soooo daaaarrrn close :)
Wow, man. I'd have thrown that thing through the wall. You have the patience of a saint.
Ha ha, beat me to it!
I just told my wife the same thing! 😂😂😂😂😱😱😱
Just to be clear...my inclination would have been to throw it through the wall!
Lol , He looked like me trying to fix 1970s size solid state components and sometimes I threw those at the wall.
I'd buy the customer a new one just so I could throw it through the wall.
The LEDs were put there to blind the unauthorized technician trying to fix it.
I think you just need more flux in the capacitors.
(sorry, someone had to say it)
You're not far from the truth. If he used flux, the chip would stay in place.
I usually find your amp repairs cathartic, this one almost gave me a coronary!
I really don't think that was flux...I think that is solder paste for SMD work. I was screaming at the screen!
mee too, buddy
Me too.
Had one of these little amps from almost day one. Great little amp, never had a problem with mine. Good sounds too. Got the Vox MVX 150 head, love it. Super sounds.
Love the video, but a couple tips on the IC replacement:
1. You need an antistatic strap and mat if you plan on more SMT repair.
2. WAY too much paste. I actually almost never use solder paste, there is a technique with an iron where you can reflow pins with no paste. And I've never used paste with an iron, only hot air or oven reflow.
3. You can never use too much flux. Flux is your friend, especially the thick gel flux.
4. Replacing ICs like this is IMHO much easier than most tube amp components, once you have the equipment and get the hang of it. If you have a hot air rework tool and a good iron, that should take care of 90% of what you run across. I've taken ICs just like the TI chip on and off boards repeatedly, about as hard as removing a piece of tape.
5. With hot air and flux, you don't need to even hold the chip down or get it perfectly aligned. The melting solder will self-align the part. Sometimes holding it down makes things worse. If the air out of your hot air tool is blowing parts off the board, your airflow is set way too high.
6. The majority of digital amp circuits I've seen in products are taken straight off the IC data sheet as a standard circuit, so those schematics in the data sheet should help a lot (they're usually the exact circuit on the board). Also, it's safe to bet that if a product has a mono out but a stereo chip, the chip is wired in Bridged mode. The schematic for such a design in the data sheet will be a big help in that case.
7. I'd guess the clicking noise is the IC protection circuitry cycling on and off.
My issue was I ordered flux in a syringe. The clear stuff. They sent THIS.
And thanks for the tips!
@@TheGuitologist No prob, thanks for your videos! And thanks for the data on the nutube, that's a weird beast. You don't see many tubes that require a positive bias voltage, but the nutube does. Very strange....
@@TheGuitologist i can aknowledge what he said. I was used to mess with those chinese class d amps that are easily found on aliexpress, and many are tpa 3116/3118 with the same form factor and, once you get the hang of it, its not too hard to solder them. One thing that may help is to actually glue the chip to the board and then apply heat. That way, the glue will evaporate and you can tack the ic easily with the soldering iron or the hot air station
Just beware about trying too many times with the same chip, as they will be damaged after the second or third time you apply heat to them. My advice is to do some training with an bad chip and then do it right the first time with a good one, you probably killed the ic long time before getting it right to the board haha
Also, if you search on the spec sheet, those chips have kind of an status indicator output that you can hook up to a led and read the "fault code" (it's supposed to blink or light up in case of some abnormal condition), so you can troubleshoot if anything goes wrong at the output
Wow... that's a long text BUT JUST ONE MORE THING =). You may know that, but class d needs filters at the output, if you test the signal output directly from the ic legs, it will sound like shit with a lot of high frequency
Again, sorry for the long text, just sharing my 2c on working on these smd amps =)
@@TheGuitologist Therein lies the problem with the terminology - Solder Paste isn't the same as Solder Flux. Solder Paste is Flux with tiny solder balls suspended in it. Solder Paste is what you wanted which contains no solder balls suspended in it. You may have been trying to order a syringe of Tacky Flux and the sent you the complete wrong item :(
Great tips Mark Bridges!!!
"I'm not used to dealing with components this small"
Nice low-key flex Brad, LOL :)
That's what she said... : )
I think you should have used flux instead of solder paste.
No smd expert here, but I watch Louis Rossman almost religiously, and I know he uses flux paste by the bucket when desoldering/resoldering chips :)
It's all about the liquid flux.
Yeah liquid flux all day with a curved solder iron tip. I'd also use kapton tape when using a heat gun to unsolder chipsets. Great content though, thanks!
The bigger the blob, the better the job.
I know I always go with flux capacitors when I'm working on electronics.
@@davekimball3610 The bigger the knob the better the job
That surface mount stuff is indeed throw away technology. Thru the facade of portability, everything is shrunken down. The components, cost to manufacture, service and support... it's all cheap by design. With a retail price of $149-$219, this thing was never meant to be serviced.
you should'a got FLUX not solder paste. order from louis, his spooge is the best.
How do you solder with flux?
@@cyfur7858 Flux get's the existing solder fluidly again, so you reuse it and don't flood the whole thing in big blobs of tin like he did. If he'd have just used the flux in this tinning paste, he would have been fine at first try.
But first you leave the stuff INSIDE instead of unsolder the heart of that thing as a first action. Unless you haven't found out, how the stuff works, don't rip it apart. Because the chip was most likely not even damaged because it is surrounded by security circuits - stuff he never understands, because he doesn't even care.
Man, i unsubbed his stuff because of his enduring shady actions like this one and again i watched it :( .
YT resists in not any more proposing me the guitologist, half of all proposed videos are guitologist, don't know why, so i got tempted again, wasted time again and now i'm angry about myself.
@@werner.x I agree with Cy Fur. While I was watching it I was wondering the same thing about just using a liquid flux. I used to repair cell phones and the components do get small.
@@cyfur7858 LOL!
@@werner.x No, heat gets the solder to melt. Flux acts as a cleaner and wetting agent. The paste he was sent is composed of flux and solder balls, but he put way too much on.
Should be called: Brad buys $500 of new tools to fix a $50 amp
Yeah! And if he really want's to fix that stuff in the future that would be just the beginning. Back in the days, you could repair stuff with a soldering iron, adjustible powersupply, signal generator and some bits and pieces. Nowadays you need a real SMD soldering station, a microscope connected to a screen, a reflow oven and the patience of an angel.
It's new price is equivalent to $195 here in europe.
Now I wanna see Dave from EEVBlog work on JCM 2000 Marshall head.. to balance the planetary equilibrium out.
That would be awesome. I’d love to see the look on his face when he can’t figure out why the bias runs away...or why anyone would put a set of EL34 on a PCB.
@@TheGuitologist have you ever worked on a Victory? I understand their lunchbox heads are on PCBs.
Dave never puts anything back together. But if you want him to look at it, just throw it in the dumpster in his building. He'll find it.
@@TheGuitologist I've had my DSL50 since about 2000. It was my only gigging amp for years, but it burned up the OPT at a show. It was over a year since purchase, but Marshall (give them their due) said they would repair it FOC and arranged collection and delivery. It came back again, then the same happened within a few months, so they fixed it again. The same happened AGAIN, so they fixed it and meantime I bought a Mk2 2203 via ebay. That became my gigging amp and the DSL50 relegated to home use. Around 2010 or so, I decided to take it apart myself and see if I could spot anything. I found several of those valve socket pins on the PCB with dry solder joints, so I re-flowed them all, and it's never had a problem since! I was happy Marshall did all that work repairing it each time FOC, but I don't understand why they obviously never properly took it apart and did some digging into the root cause. Maybe solder in an OPT and replace the two power valves was cheaper in tech time and parts than looking for the root cause...
Yes but Dave would say "that joint is as dry as a dead dingoes dong, who soldered that, Stevie Wonder".
I have exactly this little amp as an emergency backup because it's small a f. I also use it as a practice/songwriting amp at home to avoid having to switch on a full tube amp half a dozen times a day.
The amp is great. It sounds good; as it's so clean the absence of a loop won't be an issue for most players; it is loud; it is inexpensive. Sure its size implies some limitations.
As for reliability - so far so good. As with my other amps I take care not to plug the wrong shit into the wrong socket. If it malfunctions due to no fault of mine I will return it to the store for repair. If it couldn't be fixed I would get a replacement.
I feel your frustration but I think writing this off as "junk" is maybe overstating things a bit. I have one that sounds good, does what I want and has been reliable so far. I cannot consider those criteria to add up to "junk".
Other opinions are available.
Ok so he say dont get mesa boogie... cos he can not fix them.... there was a 3rd company have seen him slag off.... vox may well stand behind product. But may not make financial sense to pay for the product to be shipped to there repeat center, process it. Ship it back. When they could just say sod it here you are son have a new one.... and it did not brake from bad cheep design, or manufacture. But being connected wrongly to somthing.... wonder if he subscribes to same idea as trump... I must be the greatest, because I tell you I am the greatest
Your probably the type of person that would be fine with buying a car that couldnt be repaired. Starter gone out?! just throw the whole car away and buy a new one!
@@VashStarwind ok how many hours you spend trying to solder the components. Times hourly rate, add in cost of parts, shipping costs. I am the sort of person that dose research 1st, practice methods, than apply knowledge. Review and lurn. Just cos I work in the space industry, making a mistake there can get pricey. When I can not fix something, I do not blame the engineer who designed it. I find someone with knowledge, skills and tools to fix it. He guessed at the fault, lacked to skills to fix it, did not get the right solder and flux to solve it, the blamed other people. I dont put screws in with a hammer, cos that is all I can find.
@@bobsmith-fp6yz What are you even talking about?
@@VashStarwind economics of repair. If you pay some one 20 per hour and it takes them 5 hours to repair, complaints ext. Shipping cost spend all add up, so spend 150 to fix something that cost 120 not good. So replace it. The man in the video had little or no idea about what the fault was, had little experience with surface mounted components. Used the wrong stuff to apply the component. The man in the video said that vox were rubbish because he could not fix them. This is the 3rd time he has blamed company's for making bad products because he was unable to fix them. If my car stopped working the 1st thing I would do is make sure it had fuel. So no I would not throw the car away. But if my mechanic said cant fix general motors, cant fix Ford. Then it might be time to find a different mechanic.
You would have been better to remove all of the solder from the pads then to do exactly what you did at the beginning, heat the chip until the solder on the underneath heat-sink melts and the chip is fixed to the board with the legs aligned. Then instead of solder paste, use an iron with a much smaller tip than yours has and solder each leg independently.
Those little bubbles are tiny solder balls and you need to use you solder iron to melt them and hopefully get them to adhere to the closest solder joint or your iron. You also have a solder short between C108 & C110 from when you put the first massive glob of paste on.
this literally is the best amp i ever had but i expect that i’ll have to replace it if i plug in it in wrong way since it’s too tiny to replace separate parts and fairly cheap in price
That intro was perfect
A viewer made that. I added the silly audio.
@@TheGuitologist Silly audio? Are you saying its not the original universal audio? :)
@@3dlabs99 , the original Universal audio would have burned up in the fire!🤔
The tick makes for a pretty good, single-tempo metronome. It has a good beat. You can dance to it. I give it a 4 on the Bandstand.
If you get the joke, you’re probably as old as I am! 😂
James TheDoctor Duncan 61
comajoebuck999 64 so yep, pretty close. 😂
My man is making lemonade out of a lemon, I like your thinking! HA!
American Bandstand.63.
Ashamed to say but, why is it sometime so funny to laugh at someone else's frustrations? That loud F bomb at the 43 minute mark was all I needed.
because we have all been there, I would have smashed the thing
I know for a fact that if you let the board soak in the mud down by the river for a year then hit it with a hose and scrub the shit out of it. It would of just popped right in easy peasy.
The Owner: “I hooked the amp up wrong and messed it up.”
The Guitologist: “I’m not sure if I diagnosed the problem correctly. I got the wrong solder paste but I’m not waiting to get the right stuff. Also, I’m not experienced at soldering stuff this small.”
The Conclusion: “This product is junk!”
Right? I don't want to be mean but a more fitting title might be "DO NOT ASK THIS TECH"
I'll be happy to see a part 2 though.
That's the unfortunate nature of cheaper/more complex products.
Classic valve amps tend to be expensive because of tubes (and market value) but relatively simple in design. This makes them economical to repair.
However this tiny unit uses modern commodity devices (cheaper) and more complex design (switching power supply, switching amplifier). To some degree, you can't make that easy to repair. Certainly not economical.
Take Louis Rossmann, the Mac repair man. He repairs Macs because they cost more, so he earns more. Other laptops are similarly easy to repair, but much cheaper.
Kash Kustomer I actually watched it all the way through and I agree with the notion that we shouldn’t support companies who don’t support the product. That means the company is junk not necessarily the product. It was damaged by the owner. This would be like me dropping my iPhone & breaking it. Then complaining that it’s junk when I soldered in a replacement chip with my hair dryer and that didn’t fix the problem. Long story short...I think he’s right in the wrong way.
I've seen a number of bassists playing through similarly miniaturized Class D solid state amplifiers (maybe about the size of an old portable cassette recorder) that put out 300 watts or more. Sooner or later somebody will probably ask Brad to repair one of those......I'd love to see what those things look like on the inside.
I tried to contact KORG twice about a replacement part for my TR. They never replied. Thanks, KORG. Almost as bad CS as GIBSON, who ripped me off in 1991.
Lmao It would be a Gibson guy bitching about something that happened 30 years ago
@@MrJizzinmypantz Christ... was 1991 thirty years ago? I'm going to cry. Or perhaps break a hip. Damn it my day was going great until now. And I just shit myself. Noooooo
@@punkassfunk No, 1991 wasn't 30 years ago- it was "the year that punk broke".
@@patrickfoster4586 why can't it be both?
@@MrJizzinmypantz I'm already over getting ripped off yeaterday..
At 34:35 you accidentally bridged C108 and C110. Like others mentioned, you need to use flux instead of a paste, because soldering paste is actually a solder in a paste form. That's why you've bridged all this legs together so easy and some other components around.
Welcome to the 2020's. I work on that size stuff every day. Invest in a preheater to get that slug warmed up. Once the slug is connected, lots of flux and pin by pin. I also agree with not buying this junk.
Brad, I instructed MIL STD 2000 Category "C" "Electronics Assembly, Wiring, and Soldering", for Boeing, under their D 1 9000 Vendor Quality Program, and I agree with Louis Rossmann's "flood method of fluxation", although I would add the additional step of monitoring semiconductor temps in the area of any heat gun modifications.
Rossmann sells "No Clean, but clean it anyway flux", that's the ticket for flowing semiconductors.
Some boards in SMT/SMD have ten or more layers; making "stray capacitance" an issue. Try Techni-Tool, I've spent paychecks there, already....
Where the VOX design fails is that vacuum tubes and semiconductors, regardless of era of design, when utilized in hybrid fashion, require more than adequate heat dissipation. As such, the Korg Nutube 6P1 should've been "built onto an island"...
Brad, As someone else mentioned, that paste contains conductive balls of solder which were pretty clearly shorting the pins ( no need to use solder when using that paste because it IS solder). I think your diagnosis was correct that the chip was bad (barring any other output circuitry between the chip and the output jack). You could have also checked any of the SM caps for shorts on the output. I really think the paste did you in here though. They sent you paste instead of flux. Use the Amtech flux, about $15 per tube but worth it (don't but the cheap counterfeits off of ebay - lots of fake flux there).
No, the paste is just flux. Really bad, sticky flux. It isn’t solder.
@@TheGuitologist OK, I will stand corrected(while sitting:-) You have the container so it should tell you on the package whats in it. They could indeed be just bubbles then - really hard to tell from the video.
@@TheGuitologist You may have ordered flux, but that is clearly solder paste, not what you wanted to use, especially in the amounts you were using it.
All of that paste left on the board is just an accident waiting to happen. You don't need any more than the surface area of each pad (toothpick or tweezer tip does alright). Use just enough air flow to get the heat to the board and component without blowing the parts off, and the surface tension of the solder will pull it straight. A fine-tipped iron with solder wire no wider than the component pad can touch up any questionable joints. Liberal use of low-solids flux helps tremendously, too. SMT is a pain, but if you go at it with a scalpel instead of a hammer, you'll have less aggravation.
Yeah, he shouldn't have put any solder paste on it at all, no need to when you've got flux and solder. You can see in the last close-up shot of the board (48:20) that C108 and C110 are completely shorted by a big blob of solder paste.
A job like this for someone with SMD experience would take about 5 minutes.
@8:46 There's the problem right there. Wrong caps. For that model they should have been Jackoffs. Yep. Definitely Jackoffs.
They meant to, it was just lost in translation.
scott s 😂😂😂
same with the mistake made in the first place and soldering wrong at some point
I've been fixing shit for a long time, if I can't figure it out I get the documentation, i.e. wiring diagram, if I can't retain the data needed to make a repair and I can't figure it out ...DON'T BUY THIS SHIT!!!! LOL
Dr. Brad just proved this point to all!
You bridged c108 and c 110 together while soldering in the new IC.
I noticed this too!!
Searched the comments to see if anyone else saw this..
I saw it the moment he did it, was waiting the entire video for him to discover it. With some luck that pulled signal to ground....
Suspect you cooked the chip during your multiple attempts to remount the chip. Maybe even melted the silicone inside with all that paste and solder. I've been there and done that many times myself. I'd try once more with that 2nd chip you got, without ever using the paste and only using the solder that is on those circuit board pads.
I doubt it, he didn't seem to be using that much heat for that long to cook it. There's a giant ground pad in the middle underneath that chip as well, which would soak up a lot of heat. In the last view we see of the bare board, C108 and C110 are completely bridged with a blob of solder paste, and just the general level of solder paste mess on the components around that chip give me concern considering he never showed that it was cleaned before powering it on again. Solder paste was a mistake, there was no need to use it for this type of work. He should have just used flux and replaced the solder on the pads with fresh solder, sat the chip in place, and used hot air to get it on there.
if he touched it, its ruined.
the tic sounds exactly like the motion tracker from the movie Aliens. so that's cool
I was thinking new metronome...lol
haha, vox is on to us!
"They're coming through the walls man! "
I still haven't quite forgiven Vox for taking the Pathfinder 15R amp off the market. An excellent little solid state amp with a rich creamy tone and real spring reverb. Dumb move Vox. Irritating.
TheColonelKlink I love mine too
Glad to see amp repair vids again, that's the whole reason I used to watch you.
I love your channel and the work you do. Let's break it down. The issue isn't the amp or Nutube technology. A user plugged something in where it wasn't supposed to go - and they accidentally damaged their equipment in the process. 🤣🤣🤣
This story has been told a thousand times, it has nothing to do with any problem or short-comings of Nutube technology. I've bought a bunch of these amps and have been experimenting with them because they're cheap and just like you I was curious as to what was going on. I've done all types of mods and never managed to destroy one of them! When you break it down, there's nothing new here. VFD tech has been around for decades. It's cheap, reliable, reasonably safe to work with and the sounds I've been able to get out of these amps have been *** INCREDIBLE! *** BTW, the Eco & Pwr switches on the rear are part of the EU directive. Instructions on how and why are in the Vox user manual.
The discussion about "Right to Repair" is a separate issue. I see your position on this - it's extremely frustrating. I don't like it either. However, there's a bunch of new gear out there from all your favorite vendors and they all restrict access to schematics for their newest gear. Vox not providing a schematic to repair this particular amp is no different. Unfortunately, you were on the back-foot from the get go. It helps to have all the correct schematics, tools and supplies when taking on a a job like this. FWIW I still love Vox tone and will continue to buy their stuff. Thanks again for an entertaining video. 👍
he also bridged something that wasn’t supposed to be
The trick with this kind of soldering is to let the surface tension of the solder do the work. When you first got the chip in place all you needed to do was play the hot air over it and the surface tension of the solder would have pulled it in to place.
Drew knows the craic but even so it's still easier said than done with any of this titchy surface shit.
Agreed. He was so close right off the bat.
My mistake was in not realizing the paste contained solder. I assumed I’d gotten some version of what I ordered, which was supposed to be just clear flux paste! This is just lack of experience on my part. No wonder my work kept filling up with solder!
@@TheGuitologist Bruh....
@@TheGuitologist Ah ha... Yes, the stuff you got is used when the boards are made. It is screen printed on to the solder pads, then the components are mounted. It's sticky to help hold the components in place while the board is transferred to an oven to melt the solder paste. I assumed you knew what it was because you can use the way you were. Clean the pads, apply the smallest amount of solder paste, place component and hit it with the hot air. Oh, yes. I know a place that sells genuine Amtech flux... Store.rossmanngroup.com ;-)
Much admiration for your even attempting to do this. I would have hammered this thing into oblivion very shortly into the repair attempt but you kept after it over & over. Your patience is admirable!
It is pretty obvious this is a throw away when broke product. It doesn’t take a rocket scientist to figure out your man hours alone exceed the price of the unit. Your attempt to repair it was pretty humorous though.
From reading the comments on the video, it looks like this video has become an ad for your buddy Louis Rossman.
One last thought you should not charge your client for your clumsy attempt to repair an unrepairable cheap product. You should be satisfied with your TH-cam money on this one.
Being a throw-away product is probably right given the price and for the manufacturer the time and money between phone support, shipping and repair. Though these really aren't that old of products yet so kind of bs that they wouldn't be able to provide the customer with a replacement at a discounted rate if they sent it in, at the least if they're not going to provide schematics.
On the other hand, it doesn't take a rocket scientist to fix it either. If he had more experience with what he's attempting to do here, it wouldn't have been so frustrating or taken up as much time. But yeah, charging a customer for a learning experience on surface mount soldering small components is probably a bad idea. Better to just find some junked scrap that won't cost you anything to practice on. If the Vox was something he acquired for free or a few bucks and wanted to take a shot at fixing it for his own curiosity, it might have been worth it. Without a schematic and prior knowledge, the time just isn't worth it for himself or a customer. (Sounded like he was just charging the guy the standard bench fee for looking at it and not a repair fee though which seems about right).
C108 and C110 got shorted together by excess solder paste. I assume they look like the one common GND net anyway, but worth checking out as they are around the output and the bootstrap cap connections.
Uh oh, I love your videos but you messed up here real bad...
What most likely happend is that output IC is in bridged mode (meaning that one of the output is passing normal signal to the one connection of the speaker and the other is passing inverted signal to the other connection of the speaker) and when the output was plugged in the input of the other amp one of the IC outputs was shorted to ground and it blew. Each channel on ic has positive and negative input, and when in bridge mode one channel has signal on the positive and the other has signal on the negative input. Which explains why you didn't have any signal on the left channel.
Now the fuckup...
Solder paste is basically flux with small solder pellets inside (those "bubbles" you saw between IC pins) which give it that silvery colour. You apply it to the PCB pads, and then put the IC in it's spot and blast it with the heat gun and it solders itself in. So when you tried clean it off, it got between other components and when you blasted it with a heat gun you created shorts, most noticieably at 34:31 between C108 and C110.
Since there weren't any sparks or pops when you plugged it in, maybe you didn't short power lines and there isn't anything else blown in there.
I did notice c108 c110 bridge too. I can understand the SMD required different soldering techniques from through hole components.
30 years ago you could own electrical gear that had 2% of the components and the same amount of facilities
Wish i could've been around to buy real gear brandnew.
*Brad you tried to repair this amp and there's no failure in trying.*
Huge props to Brad for having the patience and know-how to deal with those surface mount tiny little F!@#$%ckers!!!
I own an orange micro amp which also has a class D power amp and it also makes a ticking sound! I just kind of thought, that's just what those class D power amps do? but I did buy it second hand so I'm not 100% sure. but it is not noticeable when you are playing and not an issue for recording or rehearsing or practicing, just not a huge confidence booster when you have an important gig coming up LOL.
Give drag soldering a go, save yourself a lot of headache and its about 100 times faster than trying to work with paste and hot air on a big (for modern surface mount) chip like that. Those little bubbles are solder balls, conductive, and can easily short out the chip.
The only time I use solder paste in rework is when dealing with concealed pads that are impossible to hand solder.
There's a giant ground pad underneath the center of the chip. You're never going to get that soldered properly without using hot air.
Yeah I was confused when he pulled out the solder paste, should have used flux. The only time I ever use solder paste is for reballing BGA chips, which I find easier to do than dealing with individual balls.
Take a look at 34:40 and see what takes place in between c108 and c110 :-)
Looks like you had it from the start, then you dicked around with the paste and messed it up. If I recall from watching Louis, he doesn't dick around with the paste much. Just wets the pads, goes crazy with flux, and uses heat to flow the chip into place. Also whatever is used to put on the paste looks way too big. Perhaps the lead off a 0.5 mechanical pencil would be closer to the right size and dab a gob from whatever will stick to that. Alternately look into those fine-liner brushes from a hobby store that's only a few hairs thick.
Also "reverse action tweezers", may make this somewhat easier. The ones with the offset angle to 'em.
Of course it's a bit hard to say from just watching. Seems like one of your kids are about old enough to start doing this, perhaps if they have steady enough hands maybe their younger eyes would see better to place the chip with tweezers?
Also use a hair strand of copper wire to alligator clips as the probe, and use the schematic for the output chip itself (will tell what pins should be getting what, at least we already know input signal is there) and see what voltages are making its way to the chip. Might have to trace backwards from there, since the problem is happening at the output chip. No docs from Vox, but TI seems good on their part - so work with that bit.
I was genuinely excited when Nutubes where first announced. They finally seemed like a decent alternative to the ancient vacuum tubes. But the fact that they are still only used very rarely shows how bad implementing them must be.
I honestly can't believe that vacuum tubes will still be accessible in 20 or even 10 years. So, it will probably be all DSP in the future.
Not being able to repair anything is simply the downside of making everything as small and cheap as possible, that's nothing I would blame Korg for. Any small amp in this price range is probably impossible to repair.
Vacuum tubes are still going strong, doubt they will be inaccessible in 8 years from now
Glad it’s you and not me, brother. I’m a Bible teacher. I can’t be dropping all those f bombs. 😂. I wouldn’t dare try it. Kudos to you.
The “eco” mode usually shuts the amp off after a certain amount of time not being played through.
A soldering iron is not used in surface mount circuitry. The pads are cleaned and then you apply a special paste which contains solder and flux to the pads. The component is then placed on the pads and the heat gun is used to flow the solder/paste combo which makes the connection. Solder flow guns come with various diameter tips to precisely place the hot air flow just where it is needed. Too much heat from a soldering iron can destroy these small components as they cannot dissipate the intense localized heat. With the right equipment of course any job becomes a pleasure to do.
I've watched Louis Rossman vids micro soldering is a whole different ball game he does make it look easy. Have you been following the" Right to Repair bill" Louis has been lobbying for ? addressing the issue of 3rd party repair folks getting schematics parts etc?
there are laws preventing people from 3rd party people repairing stuff? thats stupid as fuck.
He also has a $10k microscope and probably a $1500 rework station and couldn’t fix a tube amp. But yes, I’ve been following. I support his efforts on moral grounds.
@Kobe Bryant True, but wrong guy bro.🤘🔥🤘
@Kobe Bryant Anything which is designed to not be fixable is junk. By "fixable" I mean serviceable by a regular technician with affordable tools
@@pilotamurorei Think its more about manufacturers making it difficult for 3rd partys by not selling parts or schematics etc even when they wont offer repair Vox an example.
46:15 "if I could somehow get that thing to stay right there...."
As someone who used to do micro-surgery like this on SMD TV tuners, might I suggest that you use an iron to solder at least two opposite corner pins first to hold the IC in place before using the heat gun.
You are a bit unfair : The item is clearly not intended to be repaired. Even though you had a schematic, the right items and experience/competence to do the job on that SMD you can't repair it at a realistic price. The amp sells at/around 200$..
It's the same thing with almost all electronic appliances of the XXI century...Not only Vox/Korg.
That's why so many people(including me) like to watch vids from people working on tube circuits, or at least discrete throuh-hole ones..
ant Sor doesn’t change my reckoning. People shouldn’t but this crap.
I think the standby switch is just a gimmick to make it seem more like a real tube amp. I wonder if there are nu-tube HiFi systems and what the tube hi-fi buffs think of the nu-tube. LOL say that 10 times fast. LOL "JACKCON" WTF lol sketchy-est brand name EVER rofl my amp sounds so great because of the JACKCON brand caps LOL too funny. you would think some suit and tie guy at the company would be like "come on guys we're not really going to call it JACKCON are we?"
Brad....frustrating to watch. I can only imagine how frustrating it was for you. As most electronics produced these days, that amp was never intended to be repaired at the component level...assembled by machines to reduce costs...not telling you anything you don't already know of course. Kudos for taking a shot at it!
If you look at the top of the screen @ 34:40, C108 and C110 solder bridge together. (Edit: some of you already noticed)
Hey Brad, you should have used flux to clean the old solder and pre tin them with new solder (thinly). Then cover the pads with more flux then align the new chip, After that you either solder each corner and run it or use hot air.
Pretty much killed my desire for an MV50AC. No schematic is pretty much saying "it's crap and who knows how the Chinese wired it, just buy another one". Entertaining video though. I'm thinking "that chip doesn't look THAT sma-Holy crap giant finger!" That chip is reaching my limit of things visible, let alone its contacts. Can't believe sixty watts can flow through that little thing.
I felt like I was looking in the mirror at times during this video, especially through the tirade of expletives. Surface mount is NOT for the faint of heart. I applaud you for being man enough to attempt something you knew would be challenging AND share even an unsuccessful attempt with us. So many people project this fake, carefully edited version of themselves to the world. To be unafraid to let people see you struggle is a sure sign to me of a person secure in who they are.
With that said, I’m surprised that the guy decided to go through with trying to repair this. I don’t know your rates, but with the level of skill necessary to do this stuff, it seems to me that with that amp being so inexpensive, I don’t know how it would have been worth your time to do much more than unscrew the cover, visually spot a solder joint that had popped loose, re-solder it, and close it back up. But again, I applaud your willingness to give it a shot if that’s what the customer wanted.
We discussed it up front. I suspect he just wanted to see how I’d fare on SMD soldering. Not good is the answer.
@@TheGuitologist , "A man's got to know his limitations" as Dirty Harry said. Unfortunately, the only thing that helps one overcome ones' limitations is *experience*; gaining experience means that a person has to be willing to fail, and able to learn from their failures. Not everyone is......but you're willing to commit your failures to Internet immortality, which is braver than most. That said, most areas of modern life involve specialization, which is why we see a pulmonologist for breathing issues and a urologist for pissing issues! The complexity of modern electronic devices is like the complexity of the human body: It is difficult ---- not impossible, but difficult, and unlikely ---- to be an electronics-repair generalist and to simultaneously be efficient at repairing anything and everything, especially as the technology keeps changing (which is one of the reasons that manufactures used to provide schematics, service bulletins and updates, repair seminars and so on). Virtually anything is repairable, with the necessary tools, experience, and relevant information; but the economics of the time involved to do the repair are a whole other issue.
The Guitologist That sounds reasonable. I suppose that is one of the few positive aspects of today’s “disposable” electronics. This is a little twisted, but to me, when some gizmo of mine breaks, I sometimes get a little excited that now I get to crack it open and see what I can do to either fix it, repurpose it, or at least learn something new. And if I fail, no loss. I was going to have to replace it anyway.
Wait... He connected a tube amp input (=1M ohm load) into the speaker output of the Vox? No wonder it couldn't handle that, it's a class D power amp. Trying to swap the chip was a brave move, respect! But I have another idea that might still save the amp from landfill:
To fix it I'd just replace the complete power amp circuit with one of those universal class D power amp module PCBs - very easy and cheap. The original circuit is probably very very close to one of those anyway. I actually bought a complete power amp PCB with the same 3118 chip just recently for like 8 euros or so from a local shop (haven't built the amp yet). I'd also include a load resistor that disconnects when the speaker lead is connected like in the original. If there's not enough room in the original housing (and if it now works), I'd put the whole mess into a larger box. The amp looks a bit goofy anyway so why not...
By the way, even then the cost of parts for this would be less than new power tubes of my AC30.
I could not agree more about product support, if they are not going to support there products dont support them. I am seeing a lot of this happening
I got the Rock version on the deal of the day for $99. I absolutely love it. Eco = it shuts down after so many minutes of no signal Good for home practice if you like to pass out during practice. Yeah, Standby is stupid. Standby = off. However, I like that I can choose 4/8/16 Ohms. Now, to your point, repair? Probably designed as a throw-away. Mine has been kicking ass for several years, so I can't dog it. I enjoy your videos - both channels! I'm right up the street in SE Indiana.
And this is why I have over $20K worth of JBC kit on my bench.......I remember going all through this stuff and its why I have receding hairline........
The standby is because of EU regulations. It is supposed to save energy.
Man it's hard. But I've done this alot. Watch Louis doing surface soldering. Chip should find it's place, you don't have to force it, and too much solder.
Yeah, me too, but it looks easier than it is.
@@TheGuitologist I think in future you'll succeed in this smt field. Thanks for your vids, I repared all amps in studio. Your stuff is very helpful.
I never cringed that much on any of your other videos ^^' phewww !
melting solder paste before applying the chip, and putting such huge quantity of solder was the best way to shoot yourself in the foot i'm afraid ^^' but well, it's never easy the first times, especially if we go by through-hole techniques.
By the way, you created a huge bridge between C108 and C110 just next to the chip. Could it be that you fixed it, but screwed it by making that bridge?
It is what we call here in England, Shit and Skim. Way the world's gone I'm afraid. I'm 74, and I've seen better days.
Its amazing what some people will pay for some cheap plastic and wiring...Do yourself a favor and just buy a Boss Katana MKII 2x12 for less and get way more for your buck..I know because I purchased one and it's one of the best amps I have ever played thru..amazing stuff from Boss..and no I do not work for Boss nor do I know anyone that works for them..just giving a shout out to some quality stuff in a world full of bullshit and fakery...peace.
Another great video. Boy, you really get the viewer right down into the muck !
As far as Vox (aka Korg !) not supplying tech support doc's, it's obvious, at least in this case, that they don't want a $219 amp to be repairable ..... they'd rather just sell you a new one :-) OR, an owner could send it back to Vox .... but they'd probably just ship out a new one for a "fee", 'coz they're not going to go through what you did!
Hi Brad,
Next time don't use a soldering paste for chip replacement, use some kind of flux.
And I highly recommend to watch some videos about computer or smartphone repair to see a micro-soldering techniques. There are many thousands on youtube.
Sincerely, Alexander
I believe Brad could buy a new Lamborghini with the money he's putting in his swear jar.
c108 - c110? I do feel your pain food. I've worked with this scale quite a bit but when I needed to change a chip I often asked the repair guys as they did that a lot more and you need real confidence. I used to make Sonar for the oil industry but got made redundant in 15 when the oil price tanked. I can't believe it actually went negative today. We were bought by a company who's name you'd recognise from synths, avoiding bots but imagine Rick Wakeman with a miniwhatsit but it was the cousin of that guy but the same family name. The CEO came out to talk to us just after they bought us and he said in the presentation that so long as oil stayed above $80 a barrel we were ok and almost as the words left his mouth the oil price tanked. Who knows if he knew, he certainly span some hooey that day. The gave us some company-branded fold-out picnic mats which was an odd gift. we called them monogrammed homeless mats.
Bout like when I wasted my time on a gibson solid state twin lookalike . bout the knobs and reverb tank the only thing worth keepin from it in the end.
I don’t think a lot of modern compact electronics aren’t intended to be repaired. They’re disposable amps, you can buy one for $150 so it would cost more to repair one than it’s worth anyway. I like the idea of these, they’d be a handy thing to throw in your cable bag for a backup. I’ve actually decided that I’m going to get a Quilter SuperBlock instead for a backup though.
What's worse, Nu Tubes or Nu Metal?
You?
@@pakiw2 sorry to offend your feminine sensibilities.
Un metal is worse than chabiddle doo deeba banda forlick griddle too wilp.
Nu metal sux, as do the Nu drugs that Nu people do.
Nu Metal played through Nu Tube technology, if you're looking for the absolute worst.
I noticed something that might have happened that could have caused the repair to fail. If you look at C108 and C110 at time 25:02 you'll notice that they aren't connected, but at 56:19 it looks like you seem to have bridged them together with the solder paste at some point while working on it. I have no idea if those points were originally connected together, and if they were then it's not an issue, but if they weren't connected before they are now...
This is a great catch, but i say they are connected on the PCB already. Because both pads seem to be sitting on a piece of pour, like, there is no debossing visible in the mask around there.
If watching Luis Rossmann videos has taught me anything, it is that you have to use a lot more flux and not use solder paste.
Also I suspect those little bubbles you see at 50:45 are actually unmolten solder balls from the solder paste.
DeDeNoM I’m realizing this is correct. I’ll give it another go.
@@TheGuitologist idk if anyone said that befor but the part with 108 was bridged to the one next to it the first time you headet up the solder paste , maybe they are bridged on the board anyway but just wanted to point that out
it's a 2 mintue work... should have practice more before doing the real thing.
Also: avoid coffee or any caffeinated anything (and high-sugar foods) at least four hours prior to working with SMT. Caffeine gives you shakes you cannot feel and messes with your ability to do precision work. I used to shoot competitively and coffee, prior to a competition, definitely is a no-no among the precision shooting community.
This is allmost a thriller to watch!
You created a short between C108 and C110 with the solder paste, if you fix that maybe it will work (check 32.02 and 48.17).
I would have thrown that unit up against the wall after all those soldering attempts. You have great patience Brad.
You bridged c108 and c110, Man I wish we weren't in lock-down, I'm down in shepardsville, I'de offer to pop up and help ya out...
It’s a poor technician who blames his soldering paste. Ha ha!
I think you bridged c108 and c110.
Dont buy it! You are the man dude. Love your videos. Found your channel during this isolation trip that we are going through. And been binge watching ever since. Im glad that we have people like you to keep our minds running. Thanks alot!
Love your videos Brad, always an honest account of you figuring stuff out. Ditto all the comments about your patience, I would have lost my shit with that thing! Just a thought, I wonder if the fault is not actually in the amp but with the power supply brick, which is probably a switch mode supply.
WTF was that intro 🤣
You just bridged the two caps up about your chip
Am I right in thinking that those capacitors have a cross on the top to give a weakpoint to prevent it from exploding?
if i remember correctly, yes, that is what it is for.
They’ll bulge at the top when they’ve exploded internally. None are bulged.
Sometimes the top of the capacitor can will be embossed with a pie-cut or pizza-cut pattern instead of a cross. I've also seen caps with smooth tops that will still bulge slightly as they fail.
@Doctor Remulak , even epoxy-encapsulated capacitors still manage to leak and corrode the leads at the bottom of the device; where it is difficult or impossible to see unless you unsolder and remove the cap. Small orange caps in 70's and 80s audio equipment are infamous for causing audible noise, not to mention leaking and corroding.
Dude that sucks. I guess they think that all surface mount component stuff is just plain disposable, I guess that means it's trash before you buy it. I saw these things when they first come out, I knew immediately that I didn't want to take a chance on it. We don't have to reinvent the wheel, traditional guitar amps are best.
Such a shame that these are junk because they actually sound pretty good.
They're not junk. That's Brad's understandable frustration talking. If you use them as intended they work fine. Brad's customer got a connection wrong and toasted something. Not Vox/Korg's fault.
Mine gets run hard sometimes at both 8ohms and 4ohms. It has pedals in the front end, often giving a pretty hefty boost. No problems at all here after a couple of years of almost daily use.
Don't bust it through your negligence and it's cool. As Phil McKnight says, know your gear.
And don't fuck it up.
@@Dead-Eye Glad you're trying to set the record straight on these amps. Not junk by any means. I've got the Rock version, bought it a year and a half ago. Still works, still sounds great.
@@Dead-Eye this and the only other person to make a video complaining clearly aren’t doing something right
they may have arrived as non-junk but thats not the way they leaving..
It's a technique error. Remove if. Clean area & remove all excess solder. Apply half the amount as you did in the first go. Put chip on and heat with the air head like you did the first time. When the solder melts you will actually see the chip settle into the molten solder. Done! You actually had it done the first time perfectly.
Hi Brad. These are cheap enough to buy two and have one as back-up. Have actually gigged with them and yet to fail me. Cheers.
Just put that money toward something that will still be around when you die.
if you plug it in the wrong way just like anything it can fail
Brad, Companies that make solid state electronics do not employ repair technicians. They employ low-wage parts replacers, and that has become the norm for other industries as well. Try going to an Auto Zone and ordering a rebuild kit for a water pump or a master cylinder. We’re a disposable society that makes things that work for a few years and are discarded for a newer model.
Went to grab my coffee and came back to the part wth the solder paste where the ic goes....I almost spit out coffee and said Brad wtf did you do lol