JBL 518S Power supply Repair and Reliability Modification JBL 443227-001 Repair

[@Bodragon]

Superb technician. Not only fantastic diagnostic skills but demonstrates such a thorough and fundamental understanding of this design and its failings. I am in awe. >

[@razenby]

Glad it was helpful!

[@noanyobiseniss7462]

This is a perfect example of a video that I wish I could give multiple thumbs up! talk about going above and beyond. You are a rare breed my friend. :)

[@razenby]

Glad it was helpful!

[@johnmcgiv1]

I love this I am 70 and trying to learn a bit of electronics and this is the business excellent narration.

[@razenby]

Thanks.. Never too old!!!

[@mattmoreira210]

That's why I'm sold on the full-bridge resonant design. No bulk capacitors getting unbalanced or switching asymmetries to worry about. I've recently combined LLC with PWM and have been amazed with the results. The possibility of integrating both the PFC and the LLC converter, eliminating the mains-side bulk capacitance, and eliminating inrush at turn-on, all at once, is very neat.

[@razenby]

Yes, I did that for a 320W commercial grow light design with PF correction. I used GAN FETs and an active bridge rectifier and achieved 96.8% efficiency at unity PF.

[@jasonshaner6954]

Phenomenal diagnostics!! I actually have a prx618s but they use the same amp module...( I feel a bit duped by the price difference) voltage doubler relay was my fix. I appreciate your time and all your insight on every video!! Cheers from the US

[@razenby]

Thanks for watching. good luck with the Amp, May it never let you down.

[@michaelcarey]

Thank you for the most informative video. I am working on one of these power supplies (operating on 240V) where one of the main filter capacitors ruptured violently (over voltage) and sprayed electrolyte all over the place, nasty stuff. I'm normally quite apprehensive working on switch mode power supplies, they scare me! I've got a schematic of both the power supply and the mains input PCB. The modifications you suggest to help keep the voltages balanced across the two capacitors are simple but very effective. Can you suggest a model/part number for the varistor? I also noted your ordered and fitted an SG2525 where the original part on the PCB was a SG3525, from what I understand the only difference is the outputs are inverted. Was this not a concern with this power supply?

[@razenby]

The Varistor on the back of the cap is any 200VDC working type. I also discovered that the so called 'design engineer' that copied the schematic assumed the series varistor (the one bridged by the relay) was an NTC whereas in fact the design should use a PTC thermal protection varistor. (See video dedicated to this issue on the channel). For the input varistor I use PTC Epcos B59860C0120A070. when the power supply shuts down, the relay opens, the PTC thermistor heats up and quickly transitions from 10 ohms to an effective open circuit preventing a cook off.. Under the same conditions, the NTC they fit at the factory just starts low and reduces resistance and voila: FRYING TONIGHT. I have both parts in stock. Either SG part works.

[@michaelcarey]

@@razenby :-) Thanks for the extra information, especially about the SG2525/3525. Sounds like this power supply is a bit of a lemon. I'll add a PTC (or a few) to the basket before I hit order. I'm going to use a Bournes DV150K4032R2 varistor. Thanks again for the great content on your channel.

[@razenby]

The varistor you suggest should work. Don;'t forget to change the mains input Thermistor to a PTC the part I have in stock are TDK B59860C0120A070

[@michaelcarey]

@@razenby 🙂

[@montybailey2427]

The best part of the video instruction is the bashing of JBL design.

[@razenby]

the 518 is no beauty but some other JBL designs are very good once modified.

[@saarike]

Excellent repair and information! Thank you.

[@razenby]

Glad it was helpful!

[@71kanon]

Hi Magic Smoke. I have two 518S amplifiers not working. Do you have the schematic/drawings for the amplifier (can't find any drawings on the net)

[@razenby]

Let me check

[@darrenwilkinson1742]

I love your work, such a boss too! Putting the board swappers to shame!

[@razenby]

Thanks for watching. The expensive spares scam prevents employment for local techs and creates thousands if not millions of tons of necessary waste every year. Keep the economy growing , take, make and throw away' as fast as you can.

[@py3ham]

I have 2 518S that are used only inside home! I gave up! There were a lot of caps problems (problems just with the EON's). It is a SHAME to JBL! At leas 1 of them exploded each half year! After that, I decide to use them as passive units and, now, I am enjoying the speakers quality! Sorry for my poor english. Hope you get understand what I tried to write. All the best!

[@razenby]

Thanks. The problem with them is that they were designed to run on 10V AC and not properly tested in 240V. If the thermal trip opens to allow it to cool down then the Power controller is destroyed. That is the problem when copying circuits without understanding them. Real design is the study of how things fail and why rather than designing something that seems to work. Whoever copied the circuit assumed that the protection device was a NTC when in fact the design calls for a PTC. I have repaired a lot of them and don't get them back once the modification is done. It costs about 50 cents for the correct part. Such a shame.

[@py3ham]

@@razenby Dear... good afternoon! First of all, thank you very much for your reply! It was of great use to me for sure! I would like to see with you if you could tell what type of terminals are used at the ends of the wires that connect the output of the amplified signal to the speaker posts. I noticed that they are of two different sizes (one for the + sign and the other for the -), but I don't know if there is any code to buy them over the internet. If you have this information and don't mind sharing it with me, I would appreciate it A LOT! I apologize, once again, for my poor knowledge of the English language, which makes me use Google Translate as the only alternative. I hope you can understand what I'm trying to ask! A respectful hug and, in advance, thank you very much!

[@wynnful]

You're 1 smart guy. Just worked on the prx618s model. Fault was no sound, signal light on with no input. Problem was bad op amp on input board.

[@razenby]

Good job. The op amps fail a lot.

[@wynnful]

@@razenby thanks. yea, they sure do.

[@razvantrance]

Nice work! I have 2 Eon 518S bought 2 years ago, i have used them a couple of times and then one didn't worked at all and the other sounded very bad with the volume up (distorsions) , for the first one i have bought new power supply and new amplifier, it worked fine for a couple of hours and then the problem with the distorsions appeared. I have warranty for the new parts but it's in the US and i live in Romania, the cost of sending them back for repair is too high. Can you help me, please?

[@razenby]

It is unlikely that the new bard will have failed in exactly the same way with Distortion as the old board, Are you sure the speaker / driver cone itself is healthy? If you get same distortion with the new board as with the old then it is likely to be a bad chip in the pre-amplifier /input board. I suppose it could be the power board but that us easy to check as you can measure the power supply +ve and -ve supply rail voltages when the fault is present.

[@razvantrance]

@@razenby where i can send you a video with the problem?

[@abhilashkrishnaonkl]

Hi bro can you tell me the output voltages i have same model amplifier board get from scrap i want use that because I am asking you

[@razenby]

Output voltages of what the power supply section ?? Main DC supply should +24V 0 -24V Nominal. It depends on the mains input voltage.,

[@montybailey2427]

I measured the 18" driver and the resistance is 2.5 to 2.6 ohms is that a normal without using an impedance meter to measure with?

[@razenby]

That sounds about correct. You have to short the test leads on your meter and deduct that reading from the test reading across the voice coil. Usually they read about 1.6 to 1.8 ohms after you deduct the meter reading offset.

[@Legend-uf1ph]

The board's 160 watt subwoofer is not working. Please help me, the power supply is not coming.

[@razenby]

Have you any electronics skills? I can send you the Service manual?

[@405line]

Really good work, I can accept this when perhaps "you take a chance on Ebay" but when you go to the likes of JBL for a speaker you'd expect better basic engineering. I wonder if this was sold at a premium price point or whether it was from their ultra budget range, then maybe I can accept that they need to do things like this in order to compete.

[@razenby]

Reliability is weak when running from 240V supply. If you turn it off then leave it off for 20 seconds. If you turn it back on in a few seconds then it is likely to blow the FETs. Design fault.

[@donhewlett693]

hi Ref a JBL518s could you give a part number farnells or rs components or spec of the varistor across the cap with the 82k resistor

[@razenby]

I thought I did that in the video. B59874C0120A070 PTC THERMISTOR, 55R, THT Farnel Stock ref: 2769018. Remember to like and subscribe please.

[@fredflintstone2077]

I have one on the bench now. I've repaired it but it's getting too hot under full load testing. The imbalance mentioned here is probably the cause as it seems to be one of the new FETS working too hard and unable to dissipate it's heat fast enough. Instead of spending a long time puzzling and testing, I will try this mod and hopefully it will be a short cut and not a short circuit.

[@razenby]

Are you talking power supply or the Amplifier FETs overhating? You most likely have a blown or stressed resistor/component in the FET drive circuit to the gate. They get hot when they don't switch fully in or switch too slow so you get heating during the slow switching edge. Ccheck all the components between the drive PWM chip and the FET gates. Also don't assume that the tracks are connected? Check the VIAs - the PCB itself is a major cause of faults on these amps.

[@fredflintstone2077]

@@razenby Thanks for the reply. The PSU is overheating. It is one of the IRFP460. They had both blown along with the 47R gates resistors. One of the main caps has the same bulge as you had. New pair have just arrived so will fit today and add balancing resistors. It works ok until you drive it to clipping level and then heats up over 10 minutes.

[@fredflintstone2077]

@@razenby New caps and balance resistors are now fitted. Voltage difference is now within 10 volts under all heat and load conditions. The IRFP460;s are still getting hot but it now takes twice as long (5 long CD tracks) and it needs to be driven as hard I'm willing to push it. (Heavy clipping from the limiter on every beat) It got too hot to touch today and was not far from blowing. The thermal device doesn't seem to do a lot.

[@frankyquadros4675]

Hi magic smoke thank u for ur reply I have JBL eon 518s power supply for repair which is dead

[@razenby]

Ok. Well I have fixed loads of them. If you are running on 220V mains then you need a modification. Where in the world are you? I can probably fit one more in before Christmas.

[@frankyquadros4675]

Hi, magic smoke I was. In UK but now I'm on vacation in Goa india

[@bergiebee1]

I have had the supporting compound (glue) go brown and short circuit in a 1500watt sub amp

[@razenby]

Never seen it break down and conduct. I am not sure what this stuff is. Some form of Polyurethane I think.

[@JakeFishkow]

I have a pair of JBL EON 618s that have the power supply issue - can you be of any assistance?

[@razenby]

I can repair them if you need me to.

[@JakeFishkow]

@@razenby send me a message!

[@angelminkov7928]

Hello good video can the model of the varistor and resistor and what is the value of the original value of NTC because it was broken thanks.

[@razenby]

Thanks, If you mean RTC601 then it is a PTC EPCOS Part# B59860C0130A070

[@angelminkov7928]

Sir sorry i see you are changing ptc EPCOS B59860C0130A070 PTC thermistor, 25 ohms, through hole, 265 V, C860 series or EPCOS B59874C0120A070 PTC thermistor, 55 ohms, through hole, 265 V, C874 series, which is better

[@richardmorley324]

Hi Where are you located ? I have a problem with prx535 there quite old now 10 years + but think they're worth preserving

[@razenby]

Near Reading UK.

[@richardmorley324]

@@razenby how do I contact you without broadcasting to the entire world lol

[@razenby]

@@richardmorley324 Hi Richard.. Yes I can do those for you for £100 each. Lead time 5 days. That is to renew all active components in the power supply and upgrade the FETs in the power output stages. I require only the electronic modules as there is a charge for disassembly and rebuild. Please email me at [e-mail]

[@DJgMotion]

I just bought a new power module for $470 from CMI and installed it. It went pop and tripped my circuit breaker. 😢

[@razenby]

That is a real shame... Thanks for watching.

[@frankyquadros4675]

Hi magic smoke how r u is it possible to up load power supply circuit diagram of JBL eon 518s I will be a great help thank you

[@razenby]

What is you email address?

[@fevax]

You are amazing!

[@razenby]

Thanks for watching

[@noanyobiseniss7462]

Nice job as usual but one thing that really bothers me is your random system event sounds going off. In a previous vid I had running I thought it was my system and it drove me nuts for awhile trying to figure out where it was coming from! I didn't reilize it was from your vid until I watched this one and it was going off again. I literally removed the sound file from my system but still had a "oh shit" moment when I was hearing it again. I did have a bad hdmi connector that would intermittently reconnect itself so I thought that was the issue but I'm not ripping this laptop apart again for that. :D

[@razenby]

Thanks. A simple repair turned into an investigation. It did drag on a bit. Other work was going on in the background. In future I'll turn the system sound off. Thanks for the tip. It took a while to make sure it was the design of the board and not a fault that was causing the imbalance. I watched it back and realized I should have mentioned that one end of the power transformer primary is connected to the VMID and was drifting way out under load on 220V. I have a couple more 518s in next week so I will revisit it. Is there anything else you would like to see? It is a shame that they have such crap power circuitry in these amps. It doesn't really cost much more to make a bomb proof power supply. It is all at the design stage.

[@Bodragon]

Same here but what I did was different. As soon as I heard it I thought: "was that me or him?" and did a quick 3 second rewind. Turned out to be him not me. Continued to watch video unflustered. >

[@Bodragon]

@@razenby Also, another good reason for customising your own Window event sounds. >

[@Bodragon]

I mean ours, not yours. I would never dare to presume... >

[@dmcbohol]

Hi there< Perhaps when you have the time, can you also do a repair or trouble-shooting of the Bose SoundDock with no audio output (but power is ok), aside from the possibility of misconnected or disconnected ribbon cable? Thanks in advance...

[@noanyobiseniss7462]

Ship him the board.

[@dmcbohol]

@@noanyobiseniss7462 Thanks but no, I wanna learn how to fix it

[@noanyobiseniss7462]

@@dmcbohol Well your in luck possibly, I have that board and if you want to pay for him to do the diy and he agrees I will ship him mine. That is of course contingent on whether he wants to do it.

[@dmcbohol]

@@noanyobiseniss7462 If I can only get a copy of the schematic diagram of the Processor Board, I might be able to fix mine 8-)

[@razenby]

Schematics of one version of this board is available at electrotanya.com. There are many variants (iterations) of this design out there but only the schematic available for one.

[@t-dubbiedubb5028]

Great repair....I have a jbl prx718xlf that has a bad preamp board...I have a video where I explain the situation about the preamp amplifier if your interested to see it..... good video!!!

[@razenby]

Yes, always interested in seeing new stuff to fix. It would make an interesting video. I only do the electronics not the driver units. If you want me to look at it then email [e-mail] . Prefer to see it before any idiot engineer has a go at it.

[@wynnful]

Worked on a few of these. Most of the time, the fault is bad op amps, mc33078 ic and tl071 ic. What kinda symptoms is your prx showing.

[@pts197066]

My friend Can you check my amplifier is a EON 518s

[@razenby]

Which country are you in?

[@rjpeace3003]

Hey can I send you mine?

[@razenby]

I do fixed-price repairs on these if you are interested then let me know.

[@Cavscout101]

​@@razenbyhow much....I've had my 518S for 10+ years. And something is up. Powers on and the immediately shuts off. Seems like a simple fix....but idk