Full 55min version of the JBL LSR308 studio monitor speaker repair. #JBL #Speaker #Repair Subscribe on LBRY: eevblog.tv Crypto Donations: www.eevblog.com/crypto-currency/
@@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 : :(
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 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!
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 !
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 :)
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.
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!
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..”
That was interesting, Dave, congratulations on solving the problem! But I’d personally prefer bottom heater and hot air to resolve such soldering issues.
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!
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.....
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.
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 😀
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.
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)
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.
@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
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.
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!
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..
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.
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.
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.
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.
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.
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 )
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?
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...
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.
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...
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! :-)
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!
