Full 55min version of the JBL LSR308 studio monitor speaker repair. #JBL #Speaker #Repair Subscribe on LBRY: eevblog.tv Crypto Donations: www.eevblog.co...
He does that for literally every product! Try getting a feel for how Dave feels about any product that he reviews! One minute I'm like, oh it's not good, then he gets excited about something else and I'm like oh it's not too bad only to feel bad again a minute later. It's hard to get a vibe of what he actually feels for the product so that I can say, well I'm not professional and I won't be using it every day so I guess that it's going to be okay for what I'm doing with it but no! I usually end up not knowing what to think about it LoL.
well designed electronics, but still cheap chinese junk, in that sense they have cheaped out some very crucial places. Plastik baffle - that will ruin the sound - poor designed cabinet, and a plastic tweeter. Not the good old JBL from back when..
@@MrMichaelfalk Yeah doesn't matter how nice your electronics are if you skimp on the enclosure. Same with guitar amps, you can have the nicest head in the world but if you get a shit cabinet you'll get a shit sound!
This channel is a gold mine, learned a lot seing you go through your diagnosing process, also, after seeing your krk videos, last week I just repaired my first pair, you're becoming my electronics mentor, thank you for the great content and keep doing what you're doing !
@@QoraxAudio musician : "Let's go back in studio to reccord my next album with my vintage valve driven guitar amp and my rack of custom built pedals! Can't wait to appreciate the sound I crafted with all that stuff! " JBL : "AD-dsp-DA". Musician : :(
I've got a related speaker, the JBL LSR310S (subwoofer) with the same issue, minus the blinky LED. Power LED is solid on, but no sound comes out. I was stumped for ages after seeing all the power rails looking good. I guess I'm going to have to learn to reflow solder now!
This was a great repair video. The detailed diagnostic footage is very helpful. ( In fact, I think this one probably should have been on the main channel.) Thanks alot!
The LSR monitors do sample the inputs with an AD/DA system. The on board DSP does fr, timing compensation and crossover with the outputs piped straight to an amplifier. It's part of how they get the measured response to look decent. At the end of the day what matters is what comes out of them, and even though they feel ridiculously cheap, they sound great. The $20k M2 master system also requires an AD/DA system for the same reasons.
Extremely helpful. I have the exact issue where one speaker work and the other doesn’t. Sounds like now I have a solution. Bought them used from the market place on Fb. According to the owner “they’re like new only used once..”
Love these repair videos. Thanks for completing the repair. As a home handyman, that thermal pad on the bottom would have scared me off. Had no clue it was that easy.
I'm guessing that the digital sampling and filtering allows them to effectively calibrate the response of the speaker for variances in assembly. Probably means less precision needed elsewhere re: ABS front panel, etc...
The reason for converting to digital is for DSP correction and crossover for the drivers/cabinet and results in a much better speaker overall for the price
Yeah, I don't see the problem of using cheap digital components in this modern age if it gets the job done well. Except for the blowing up part, that is..
Thanks Dave, I enjoyed this! one the face of it I agree with your initial assessment of the MDF/ABS cabinet, but these monitors are fabulous for the money. They really are one of the best bargains around for the average home studio. But I'm sure lots of other folks have said that. Keep up the good work!
That was interesting, Dave, congratulations on solving the problem! But I’d personally prefer bottom heater and hot air to resolve such soldering issues.
When you cut the pins off, I tend to run a bead of solder over all of the pads to make them one big blob so that no individual pad experiences forces on it from the knife. After the main plastic husk is gone, melt them a couple at a time from the outside in (never side-ways) with the tip of an iron. And finally some wik.
Please ignore this if superfluous: Dave, Could You please do a video or even a series of videos to teach people proper diagnostic methods? It strikes Me that this would be very useful - a reference to use alongside a video like this one to explain Your working. You're a great (in the proper sense of the word) educator. Thanks again!
LOL that was a real bodge repair, definitely needs redoing. I've done PowerPad components, either pre-heat to around 160C on a plate or using the hot air gun, then hot-air the chip off at 350C, it just floats off the pad, use leaded solder with a large wedge on the iron and mix up the lead-free with leaded, suck up the huge ball with a desoldering gun, do this twice - get rid of every single bit of lead-free, then run over all the pads with leaded to leave a nice raised bump of solder, then put the new IC down (heat it a bit with the hot air gun first) and then watch as it does the Rossmann Dance into place, nudge it a bit with tweezers to get it bang on and you're done. I've found using leaded solder with C511 "Crystal" flux negates the need for separate flux when reworking, a real time saver, plus it's quite tacky at about 140C so perfect for manoeuvring SMDs into more-or-less the right place by eye (before the microscope)
Not sure where I learned this but a nice way to get SMD chips off without using a knife (if there's not enough space, or it's a good chip you want to re-use), is with a piece of thin enameled wire. First you feed it through the gap under all the pins, then you scrape and solder the end to the nearest strong pad. Then pull the other end at a 45 to 90 degree angle away from the chip, and using a normal soldering iron tip, heat up each pin starting from that end. As soon as the solder melts, the enameled wire slides under the pin bending it up slightly. Since it's enameled, the solder won't stick to it (unless you linger and melt the enamel), instead the solder gets dragged out of the way, making a nice gap between the pin and the board. Once one side is done you remove that wire and use a fresh piece for the other side. Although I haven't encountered chips with thermal pads yet, I see no reason why this wouldn't work as an alternative to the knife method to separate the pins before doing the big pad. Personally I find magnet wire perfect for this, a good source being cheap little DC motors, which you can also salvage quite easily from little un-repairable motorized gadgets.
Hi Dave, I love the longer vids, also like repair vids too as they further my understanding and knowledge......thanks for taking the time to make tham :)
Definitely like the repair vids. Reminds me of the column in EA I can't remember the name of, where a technician details a repair, only this comes with with moving pictures 😀
This is a really good video 👌 Have you pulled apart your Focal's for a look around inside? I would love to see which path Focal took. I have had a look around inside my Fostex PM 842 powered monitor's and I'm quite happy with what they did, nice copper shielding at the input stage and the output stage is powered by class AB TI TDA chips, no hiss either! Amazing super flat sound. Everything that a studio monitor should be.
@EEVblog2 thanks for this detailed video. I do have one issue with this same model; it has a very low volume output even at maximum volume on the knob. What could possibly cause this? Thanks in advance
Would it be possible just replace the board? If you don’t have the testing equipment outside of a multi-meter and soldering kit. After a visual inspection shows no burnt or blown components, couldn’t I swap out boards from my speaker that’s working and then just replace the faulty board?
This type of amplifier working normally will have a voltage on the output terminals will equal 1/2 of VCC. If it's VCC the chip has a short. If it's 0v check for a short to ground on the final outputs plus suspect a shorted or disabled chip. Rule of thumb start with the part that handles the most power.
Wow bro i wish u would just get on with the show....obviously u love the sound of your voice and are really ammused by yourself...congrats....happy for ya.....
I have a pair of 305 mk Is. Or at least a pair of boxes, since one only works if I "wake it up" by blasting a really loud signal through it... then it will eventually go dead again in an hour or so. I have no idea how to fix it, hoping this video helps...
Hey bro, I just bought a brand new JBL 305p MK2 and it was playing very great first 2 days but today Its just playing at an insanely low level that i can barely hear. It's also making popping sounds here and their. Im still hearing bass but im hearing a loud Hiss noise when i put my hear close to the tweeters. Sometimes when i turn the volume knob at the back of the speakers up and down, after a while it will just start playing fine for a few minutes and then a pop and it start playing low again... Which makes me to believe maybe their is a loose wire of something inside the speaker? Im not an audio technition but I would appreciate your advice.
Instead of using the knife to cut the pins I would always use a very thin gauge wire slid underneath the area where they rise up off the board. After soldering it to pin 1 of the IC you can basically just heat up pin 18 and drag the other end of the wire underneath and out which lifts the pins off the board. Once pin 18 is lifted you can just move the iron up the chip and all the pins will come up. That way you don't have to worry about cutting the traces, but you do have to be careful not to break the wire!
Do these speakers use a seperate lower power amp for the tweeter? In that case it does somewhat make sense to do the DSP digitally if your amps have digital inputs. Doing the crossover calculations digitally is just going to be more precise and as others mentioned, doing calibration is a bit easier.
These speakers actually sound really good. I have the newer version of them and really enjoy them. I also have some vintage 70’s sansui and pioneer amps and speakers made of real wood and decent build quality. Hate to destroy the dream but my jbl monitors sound better. The acoustic design and matched amplifiers make these sing. The stereo separation is way better than the old gear.
Wouldn't have been as interesting as showing the cutting and isolating thermal masses method. Don't know about quicker, cutting pins takes seconds, and the direct iron heat application will be quicker than using hot air to heat up a large thermal mass.
@@EEVblog Agreed. That is a method I would have never thought of, and it resulted in a very clean removal of the chip without any real worry for losing any passives in the process.
@@EEVblog Cutting the pins can lift pads due to the sideways force applied when the pin separates from the ic and the blade goes in between the stub and remaining IC pin. It can help to apply just enough solder to bridge all the pads together before cutting to add strength.
@@EEVblog the cutting way i know a long time ..when hotair was not so cheap ..and we only had irons ... another technique is slide a very thin wire under te chip en lift pad by pad ( in this case hard because of the thermal pad )
Ooooh these are great monitors!! I bought a broken pair on eBay and fixed it myself, Saved $200! Power boards have issues for sure, they made down to a price.
After so many remarks about audiofoolery woo-woo we get to see Dave go on about silly class D amplification and power mad class A, and Focal products better than JBL. Still, a great, very thorough repair.
i dont get it..can you explain that for lesser educated people? Why is there an ADC in there? why is that needed, is that for the frequency crossover? Doesnt that mean that it also needs a DAC to covert it back again? And if thats the case, does it even make sense to feed these monitors a signal from a several 100eu expensive DAC, if it converts it back and forth again with that cheap internal converters? i mean they gotta be cheap considering the price?
Hi Dave, I see that you are using the new PACE soldering iron here in this video. But I can't tell what hot air station you are using, can you let us all know which one you use, which ones you'd like to have, and which one you've tested and thrown into the garbage bin? Keep up the great work! :-)
I wouldn't be happy with that either. That alignment is not good enough. The speaker works but its a bodgy repair. If this was a repair for a customer and they opened it to check my work and saw the chip misaligned like that, they'd think i didn't do a good job and wouldn't trust me again.
"port is wizz-bang designed" actually there is only one correct port size/length for the box dimensions... i remember i had a book back in the 90s that went through all the math/physics and included formulas to work out port length/size...made a nice ported box for my 12in sub ..i wish i still had that book..went into info on crossovers and multiple speakers in the same box.. im pritty sure it was this one..from 1981!.. "Designing, Building and Testing Your Own Speaker System-- with Projects" available on amazon
Hi. Can I bypass this internal class D amp and connect external amp outputs to some place on the PCB? Or do I need additional crossovers to convert them to passive monitors?
I use Kemet capacitors alot myself. They do make very high quality caps that do well in harsh environmental conditions. Of course they also make alot of cheap, run of the mill caps, too.
@@simontay4851 Kemet have been doing solid capacitors like ceramics and tantalums for years.. they've only recently gotten into the aluminium electrolytic market... they are good quality though
In my case it's no sound and LED off. I checked the PCB power supply segment and everything seems ok. I just left it alone connected, then one day it just functioned ok, LED and sound. Then one day it's again dead. It just alternated like that without me doing anything. Today it is dead again.
We used to round the tip of the exacto blade, to mitigate cutting traces and come in at a steeper angle. This would make it easier to cut the leads off the chip.
no such thing as too long, I love watching the full diagnostic and repair process
Agreed you learn more going the long way. You also get a glimpse of how his brain works diagnosing the problem.
Next video will include the wait for the digikey delivery in real time then :) Naah just kidding -- I agree great with a long in depth video.
I will say that it seemed like five minutes of waving the exacto knife before cutting. ;)
Its an Australian thing, we like to wave knifes around.
@@lokig8640 haha, funny and true.
You should have opened up the good one and done a comparison...Good trouble-shoot and an excellent repair... WELL DONE Dave !!! 10/10
I did.
THANK YOU DAVE!! You really do add A LOT of entertainment factor with your down under dialect! I can watch your videos front to back. THANKS AGAIN!!
he starts off "this cheap chinese junk" then ends up "this is really well designed bobby dazzler"
Thats how you know he hasn't let his view of chinese products cloud his opinion on the design and build of a piece of equipment. Great to see!
He does that for literally every product! Try getting a feel for how Dave feels about any product that he reviews! One minute I'm like, oh it's not good, then he gets excited about something else and I'm like oh it's not too bad only to feel bad again a minute later. It's hard to get a vibe of what he actually feels for the product so that I can say, well I'm not professional and I won't be using it every day so I guess that it's going to be okay for what I'm doing with it but no! I usually end up not knowing what to think about it LoL.
well designed electronics, but still cheap chinese junk, in that sense they have cheaped out some very crucial places. Plastik baffle - that will ruin the sound - poor designed cabinet, and a plastic tweeter. Not the good old JBL from back when..
@@MrMichaelfalk Yeah doesn't matter how nice your electronics are if you skimp on the enclosure. Same with guitar amps, you can have the nicest head in the world but if you get a shit cabinet you'll get a shit sound!
it's designed in northridge,ca
Wow those 3.3 and 5V supplies are spot on!
This channel is a gold mine, learned a lot seing you go through your diagnosing process, also, after seeing your krk videos, last week I just repaired my first pair, you're becoming my electronics mentor, thank you for the great content and keep doing what you're doing !
Me : "cool, some speaker, will learn stuff on analog hardware".
JBL : A/D-D/A.
Me : "..."
Audiophile: 😱😱😱
@@QoraxAudio musician : "Let's go back in studio to reccord my next album with my vintage valve driven guitar amp and my rack of custom built pedals! Can't wait to appreciate the sound I crafted with all that stuff! "
JBL : "AD-dsp-DA".
Musician : :(
@@Damien.D 😆
I've got a related speaker, the JBL LSR310S (subwoofer) with the same issue, minus the blinky LED. Power LED is solid on, but no sound comes out. I was stumped for ages after seeing all the power rails looking good. I guess I'm going to have to learn to reflow solder now!
This was a great repair video. The detailed diagnostic footage is very helpful. ( In fact, I think this one probably should have been on the main channel.) Thanks alot!
Hiss is just an indicator of the awesome amount of POWER trapped in your system, waiting to blow you away when the music starts 🤣🤣
A mystery with twists and a satisfying conclusion!
The LSR monitors do sample the inputs with an AD/DA system. The on board DSP does fr, timing compensation and crossover with the outputs piped straight to an amplifier. It's part of how they get the measured response to look decent. At the end of the day what matters is what comes out of them, and even though they feel ridiculously cheap, they sound great. The $20k M2 master system also requires an AD/DA system for the same reasons.
Extremely helpful. I have the exact issue where one speaker work and the other doesn’t. Sounds like now I have a solution. Bought them used from the market place on Fb. According to the owner “they’re like new only used once..”
Love these repair videos. Thanks for completing the repair. As a home handyman, that thermal pad on the bottom would have scared me off. Had no clue it was that easy.
I'm not surprised by the neatness inside. It's a JBL after all.
Even if it's a cheap one, it's still decent.
as you said the important is the journey to get there, so i don't mind the length of the video, i like it!
I'm guessing that the digital sampling and filtering allows them to effectively calibrate the response of the speaker for variances in assembly. Probably means less precision needed elsewhere re: ABS front panel, etc...
Likely.
thats actually quite clever if that's the reason. Take an IR or something of the enclosure and use that to calibrate each speaker.
It's because of the time alignment of the waveguided tweeter. It's easier (cheaper) and better to do digitally.
I bet that DSP chip can compensate D class amplifier distortion levels at least at high frequencies
@@viperwizard491 The fact that the ADC is Sigma Delta also plays a big role in the Noise and resolution department.
The reason for converting to digital is for DSP correction and crossover for the drivers/cabinet and results in a much better speaker overall for the price
Yeah, I don't see the problem of using cheap digital components in this modern age if it gets the job done well. Except for the blowing up part, that is..
FINALLY, a good video after all those boring debunk and scope videos
Thanks Dave, I enjoyed this! one the face of it I agree with your initial assessment of the MDF/ABS cabinet, but these monitors are fabulous for the money. They really are one of the best bargains around for the average home studio. But I'm sure lots of other folks have said that. Keep up the good work!
That was interesting, Dave, congratulations on solving the problem! But I’d personally prefer bottom heater and hot air to resolve such soldering issues.
Dave your long form vids are the best. Thank you.
Love seeing the process you went through. I was egging you on to look at the clocks and data sooner. Bloody internal references!
When you cut the pins off, I tend to run a bead of solder over all of the pads to make them one big blob so that no individual pad experiences forces on it from the knife. After the main plastic husk is gone, melt them a couple at a time from the outside in (never side-ways) with the tip of an iron. And finally some wik.
Well designed....... Except that they all blow up!
Thanks for the vid, Dave.
I've got a dozen fried LSR305's I need to repair at some point.
Please ignore this if superfluous: Dave, Could You please do a video or even a series of videos to teach people proper diagnostic methods? It strikes Me that this would be very useful - a reference to use alongside a video like this one to explain Your working. You're a great (in the proper sense of the word) educator. Thanks again!
Thanks! Wouldn't it have been easier to open also the working speaker to easily compare what the values should be?
He did open the other one.
LOL that was a real bodge repair, definitely needs redoing. I've done PowerPad components, either pre-heat to around 160C on a plate or using the hot air gun, then hot-air the chip off at 350C, it just floats off the pad, use leaded solder with a large wedge on the iron and mix up the lead-free with leaded, suck up the huge ball with a desoldering gun, do this twice - get rid of every single bit of lead-free, then run over all the pads with leaded to leave a nice raised bump of solder, then put the new IC down (heat it a bit with the hot air gun first) and then watch as it does the Rossmann Dance into place, nudge it a bit with tweezers to get it bang on and you're done. I've found using leaded solder with C511 "Crystal" flux negates the need for separate flux when reworking, a real time saver, plus it's quite tacky at about 140C so perfect for manoeuvring SMDs into more-or-less the right place by eye (before the microscope)
Repair videos for the win Dave. Bring them on
I will give 100/100 marks for the non stop talk.
I really like the longer and more detailed videos. Good job!
Not sure where I learned this but a nice way to get SMD chips off without using a knife (if there's not enough space, or it's a good chip you want to re-use), is with a piece of thin enameled wire. First you feed it through the gap under all the pins, then you scrape and solder the end to the nearest strong pad. Then pull the other end at a 45 to 90 degree angle away from the chip, and using a normal soldering iron tip, heat up each pin starting from that end. As soon as the solder melts, the enameled wire slides under the pin bending it up slightly. Since it's enameled, the solder won't stick to it (unless you linger and melt the enamel), instead the solder gets dragged out of the way, making a nice gap between the pin and the board. Once one side is done you remove that wire and use a fresh piece for the other side. Although I haven't encountered chips with thermal pads yet, I see no reason why this wouldn't work as an alternative to the knife method to separate the pins before doing the big pad.
Personally I find magnet wire perfect for this, a good source being cheap little DC motors, which you can also salvage quite easily from little un-repairable motorized gadgets.
Hi Dave, I love the longer vids, also like repair vids too as they further my understanding and knowledge......thanks for taking the time to make tham :)
That was a ton of fun. Thanks for the project. Appreciated.
Amazing! Good work. It wasn't the prettiest repair but a repair it is.
Thanks Dave, this was a good education for me. I'm still new to smt and class D. Oh for the days of analog amplifiers and passive monitors!
This reminds me of one the first videos I saw of yours - the scam speakers from the back of the transit van!
That second crystal near the amp is possibly for the cirrus logic a/d converter.
That's more like it , a good old fashioned repair video, they are my favourite
Really loved this video. A really good watch! You're quite an entertaining character to boot.
Definitely like the repair vids. Reminds me of the column in EA I can't remember the name of, where a technician details a repair, only this comes with with moving pictures 😀
the servicemans log
This is a really good video 👌
Have you pulled apart your Focal's for a look around inside? I would love to see which path Focal took. I have had a look around inside my Fostex PM 842 powered monitor's and I'm quite happy with what they did, nice copper shielding at the input stage and the output stage is powered by class AB TI TDA chips, no hiss either! Amazing super flat sound. Everything that a studio monitor should be.
ua-cam.com/video/hhD8-faJuy4/v-deo.html
That video was a real bobby-dazzler Dave, thanks mate!!!
@EEVblog2 thanks for this detailed video. I do have one issue with this same model; it has a very low volume output even at maximum volume on the knob. What could possibly cause this? Thanks in advance
The hiss will be in the analog stage before the dsp, as its a class D amplifier ie the amp is the DAC
Would it be possible just replace the board? If you don’t have the testing equipment outside of a multi-meter and soldering kit. After a visual inspection shows no burnt or blown components, couldn’t I swap out boards from my speaker that’s working and then just replace the faulty board?
This type of amplifier working normally will have a voltage on the output terminals will equal 1/2 of VCC. If it's VCC the chip has a short. If it's 0v check for a short to ground on the final outputs plus suspect a shorted or disabled chip. Rule of thumb start with the part that handles the most power.
Replacing 100 pin QFP ic's are always 'interesting' to line up. Done plenty of those.
pretty well built we are the JBL service agents for sydney
Those crystals not sitting on the PCB ruined my day
Wow bro i wish u would just get on with the show....obviously u love the sound of your voice and are really ammused by yourself...congrats....happy for ya.....
I have a pair of 305 mk Is. Or at least a pair of boxes, since one only works if I "wake it up" by blasting a really loud signal through it... then it will eventually go dead again in an hour or so. I have no idea how to fix it, hoping this video helps...
Likely the PCB is used in different models, where space would be at more of a premium in the smaller speakers....
Love your fault-finding & repair videos, Dave.
Love the long video Dave. Great work.
Hey bro, I just bought a brand new JBL 305p MK2 and it was playing very great first 2 days but today Its just playing at an insanely low level that i can barely hear. It's also making popping sounds here and their. Im still hearing bass but im hearing a loud Hiss noise when i put my hear close to the tweeters. Sometimes when i turn the volume knob at the back of the speakers up and down, after a while it will just start playing fine for a few minutes and then a pop and it start playing low again... Which makes me to believe maybe their is a loose wire of something inside the speaker? Im not an audio technition but I would appreciate your advice.
Instead of using the knife to cut the pins I would always use a very thin gauge wire slid underneath the area where they rise up off the board. After soldering it to pin 1 of the IC you can basically just heat up pin 18 and drag the other end of the wire underneath and out which lifts the pins off the board. Once pin 18 is lifted you can just move the iron up the chip and all the pins will come up. That way you don't have to worry about cutting the traces, but you do have to be careful not to break the wire!
Mine will not power up. Does the power switch have a fuse next to it?
of the JBL legend, only the 3 letters remains ...
How did you manage to switch on the left speaker with no power cord attached?
Do these speakers use a seperate lower power amp for the tweeter? In that case it does somewhat make sense to do the DSP digitally if your amps have digital inputs. Doing the crossover calculations digitally is just going to be more precise and as others mentioned, doing calibration is a bit easier.
yes, it's normal for powered monitor speakers like these to be bi-amplified.
Love repair videos, and love seeing the whole process. Very educational.
Fantastic! I have one pair of this monitors. Now i know this acoustics much better! Thx!
Maybe I missed it, but did he ever check the fuse?
Great video! Love these long form videos!!
Nice one Dave very interesting keep the good work up
All the good Aussie phrases used here. Well done sir...
These speakers actually sound really good. I have the newer version of them and really enjoy them. I also have some vintage 70’s sansui and pioneer amps and speakers made of real wood and decent build quality. Hate to destroy the dream but my jbl monitors sound better. The acoustic design and matched amplifiers make these sing. The stereo separation is way better than the old gear.
always learning something new from you dave. good job.
You probably should have used hot air on this repair, you would have found it quicker and easier to do, I use hot air a fair bit.
Wouldn't have been as interesting as showing the cutting and isolating thermal masses method.
Don't know about quicker, cutting pins takes seconds, and the direct iron heat application will be quicker than using hot air to heat up a large thermal mass.
@@EEVblog Agreed. That is a method I would have never thought of, and it resulted in a very clean removal of the chip without any real worry for losing any passives in the process.
@@EEVblog Cutting the pins can lift pads due to the sideways force applied when the pin separates from the ic and the blade goes in between the stub and remaining IC pin. It can help to apply just enough solder to bridge all the pads together before cutting to add strength.
@@EEVblog *Dave's got plenty of "hot air" on tap so I wouldn't worry!* 😅😅
@@EEVblog the cutting way i know a long time ..when hotair was not so cheap ..and we only had irons ... another technique is slide a very thin wire under te chip en lift pad by pad ( in this case hard because of the thermal pad )
Doesn't the datasheet say Vss = Vcc - 3.3 V (Vcc minus 3.3 V)? Not that it matters, it should still be lower than 25.7 V...
Don't knock mdf, it actually doesn't sound that bad.
awesome video, never would have thaught about htese solder techniques
would love to see you doing more off this stuff ;)
just in the way you did this video
greetings from the Netherlands
Ooooh these are great monitors!! I bought a broken pair on eBay and fixed it myself, Saved $200! Power boards have issues for sure, they made down to a price.
What did you replace in order to get your speaker to work again?
308's measure extremely well for their price, will definitely go lower than the CMS40 with more texture down low.
If you have 4" CMS40's then you don't care about the really low end.
Awesome Dave!! I own these and when they break I will be able to fix them. THANK YOU!
42:20 surely de-solder the pins then bend them out of the way. Then heat the pad from the bottom? Maybe I just haven’t got to that bit...
After so many remarks about audiofoolery woo-woo we get to see Dave go on about silly class D amplification and power mad class A, and Focal products better than JBL. Still, a great, very thorough repair.
Awesome video Dave! Really liked the desoldering advice
do you know the impedance of the woofer?
Can you please post a link to the tweeter hiss video in the description?
i dont get it..can you explain that for lesser educated people? Why is there an ADC in there? why is that needed, is that for the frequency crossover? Doesnt that mean that it also needs a DAC to covert it back again? And if thats the case, does it even make sense to feed these monitors a signal from a several 100eu expensive DAC, if it converts it back and forth again with that cheap internal converters? i mean they gotta be cheap considering the price?
So what caused this problem most likely?
Came for JBL Monitors, stayed for marco reps level enthusiasm for electronics
When reinstalling a new chip use a battery powered soldering iron so as not to destroy the chip because of static electricity.
Hi, can somebody explain me why capacitors (e.g. at 11m00) are not "fully" soldered on both legs ? Often the negative one is not . Thanks !
this is such high quality content my face hurts
I would've used a dremel with a diamond wheel to snip the pins though
I see the problem. The silkscreen is wrong. There are two Pin 19s. I see 1-19 and 19-36 no wonder the electrons are confused.
Hi Dave, I see that you are using the new PACE soldering iron here in this video. But I can't tell what hot air station you are using, can you let us all know which one you use, which ones you'd like to have, and which one you've tested and thrown into the garbage bin? Keep up the great work! :-)
Where is the link to the capacitor failure video you said you would leave?
I would not be able to sleep if I misaligned the chip like that... How could you?
I wouldn't be happy with that either. That alignment is not good enough. The speaker works but its a bodgy repair. If this was a repair for a customer and they opened it to check my work and saw the chip misaligned like that, they'd think i didn't do a good job and wouldn't trust me again.
"Good enough for Australia"
"port is wizz-bang designed"
actually there is only one correct port size/length for the box dimensions... i remember i had a book back in the 90s that went through all the math/physics and included formulas to work out port length/size...made a nice ported box for my 12in sub ..i wish i still had that book..went into info on crossovers and multiple speakers in the same box..
im pritty sure it was this one..from 1981!.. "Designing, Building and Testing Your Own Speaker System-- with Projects" available on amazon
Yeah I'm guessing they use the same flares and just slap in a different length center section depending on the cab and driver for each model.
They have a current patent on the port shape, goes with the fancy waveguide on the front. Can't assure you it does something.
Hi. Can I bypass this internal class D amp and connect external amp outputs to some place on the PCB? Or do I need additional crossovers to convert them to passive monitors?
I know I'm way late, but you would just unplug the speakers from the PCB entirely, then wire those to a crossover or an amp with a DSP.
@@tboodman :) thanks
Ever seen any Kemet caps dave? Apparently there's amazing but rarely in consumer stuff
I use Kemet capacitors alot myself. They do make very high quality caps that do well in harsh environmental conditions. Of course they also make alot of cheap, run of the mill caps, too.
Never heard of kemet. I always use panasonic FM or FR series.
@@simontay4851 Kemet have been doing solid capacitors like ceramics and tantalums for years.. they've only recently gotten into the aluminium electrolytic market... they are good quality though
In my case it's no sound and LED off. I checked the PCB power supply segment and everything seems ok. I just left it alone connected, then one day it just functioned ok, LED and sound. Then one day it's again dead. It just alternated like that without me doing anything. Today it is dead again.
We used to round the tip of the exacto blade, to mitigate cutting traces and come in at a steeper angle. This would make it easier to cut the leads off the chip.
We like long and repair videos!
More repair videos please!
I did enjoy this. Thanks for sharing.