This fault can manifest in several ways. What to check and and a description of the cause with Schematic and explanation. Often missed by engineers that don't the know these speakers that well.
On my thermal imager, lnk302dn and q603 are both glowing red (80 degrees). Trying to figure out the problem. Both components were changed. Still 63 partial short on the +5v rail. One step away from giving up 🤷♂️ 😊
The 5V rail is on the secondary side of the switch mode supply. Do you have a +20-0-20V DC power supply available? (dual rail +-20V). If the main supply is trying to start but cant due to a secondary short on the amplifier side then I would expect a thermal witness where the shorted component is. However the LNK302 should not be that hot even if there is a short on the secondary side which makes me believe that you have a main power supply issue.. I take it you have metered all the power transistors for shorts. The LNK302 output should be around 12V DC. If this is low you because of a short you can connect a 12V DC bench supply with the mains disconnected and see what gets hot. Are you 230V mains only? If yes there are a bunch of components that fail and cause issues the we can just remove, Two of them frequently fail and load the LNK302 output. Not ethe buck coil is a very common failure but you get smoke, sparks and sometimes heat. Keep going you can fix it. Se the video on this issue on the channel. That's it.
Yes i have a dc bench supply capable of 60v dual plus and minus. I have changed all primary components except for the u603 inductor. I have a new inductor that reads 102 on the case 1mH but I'm scared to put it in Bcs the original inductor says 335. I really appreciate your encouragement Bcs I'm a beginner and not good at electronics but I try to read and study on it. I will continue watching your videos and trying my best. Thanks
I've injected 12v into lnk ic after replacing inductor. Nothing gets hot on the primary side I still get 63 ohm partial short on the +5 volt rail. I'm still troubleshooting this
I have only ever seen a few failures of the 1200uF caps. ESR is an effective parasitic impedance measured with an AC signal usually at 100Hz on Aluminium caps. Are both caps are short-circuit? I probably have a bundle of good used ones in old boards. My company ships to Australia every day.
1/2 bulk is 170Vdc so I don't think the caps are shorted. Just my esr tester says 0 ohms so I was curious. I've replaced all the components you recommend except for the inductor (L603) Bcs I can't where to buy it. Not sure if this could be the problem. I still can't get it to power on. Nothing to the preamp board and no 40 volt rails. There's only 9volts dc on the cap (c619) going to smps reference. (Should read 15v ?) I'll double check filter caps with a better lcr meter at 100hz as you suggested. Should I contact you via email regarding parts? Thanks for the reply P.s I do have the schematic. It's eon510 I'm working on
I have a question where is the video showin how to take down the cooling sync to get to the controll board but most important how do i fix low range hummin but stayin at one volume level its a jbl 500 i own by the way
I take it that the hum is there with no inputs plugged in? Does it get louder when you turn up the gain? or does it stay at a constant level regardless of the volume setting? and is it humming at twice mains frequency.. ?? 100 or 120 Hz? or something else?
Its hum at one volune level even when volume turn up it stays at one level hummin an the speaker remain on a 5% to 10% volume what could be causing that issue
Good point, very likely, Providing both capacitors have reasonable capacitance and not too high a level of DC leakage. Maybe measure the voltage across each cap at 230V input and see if they are balanced? When driving hard (high volume) If the caps are low C, the amp will shut down and blue light goes out and then restart . these nasty Teapo caps are well past mid life so I would recommend replacement.
Thank you for sharing this video. I have one of these unit and it powered by 110 VAC. The problem that I'm having is there is no output. I am getting my signal light when I put an input. I check the IGBT's and The voltage regulators and they are fine. Any Ideas on what can be the problem?
Could be a number of problems. Any shorts on the 4 LF FETS? (P&N channel complimentary) If you have no blown FETs then check the offline buck regulator LNK302/304 chip and it's associated inductor.
@@razenby There are no shorts. I check the LNK302 and I am getting 300 volts on the drain, 0 volts on the source, 1.2 to 1.3 on the FB pin and 5.8 volts on BP pin.
@@razenby Ok I didn't realize that there were output FETs hiding under those two thermal heat pads. yes the seem to be shorted. They are International Rectifiers (IR) Fets. Can you give me the part number for those?
I have the Eon 500 and it makes a lot of noise before it starts to play .I ALSO have to turn up the mixer for it to play . Now I am getting nothing from it . What could be the problem .
I've got 63 ohms partial short between the +5 volt rail and ground. Doing my head in and can't work out where the fault is. Any suggestions where to look? The preamp board is disconnected so the issue is somewhere in the secondary
Hmm Tricky, when in this situation a thermal imager is very useful. You can see a temperature rise as low as 1 degree and instantly see where the where the power is being dissipated. If it is an IC then it might even get slightly warm to the touch. Disconnect from power first!! Note: if you unplug the preamp the power supply wont idle correctly as the when the amp outputting audio the preamp is the dominant source of DC load. i.e it will do odd things under no load conditions. So keep the input board plugged in when checking the power. At 63 ohms the power supply should provide sufficient current to drive that the rail to 5 volts. Good luck.
Thankyou. My new thermal imager is on the way and I will receive it in a week or so. I will reconnect the preamp board and apply plus and minus 5v at the regulators to see/feel what's getting hot. I've probed the whole board and the 63 ohms appears across c1, the lm339, both audio driver ic's. 3 or 4 resistors. Anywhere where that plus 5 volt rail is basically. The blue ring tester shows the whole secondary of the transformer shorted so I guess it could be on the 12 volts going into the regulator. Thanks again.
@@razenby Ho and thanks for getting back to me. I have already did some digging for the parts. Thinking that you have found most of the problems with these, i was think it would be nice to kit the most needed parts to repair the most common problems. I think it was 5 or 6 caps 1 ic and 1 coil. Should not cost much but be a quick fix for them. Thanks for getting back to me. Still fantastic video. Helped quite a bit.
I can't remember the frequency. However, both halves of the bridge switch at the same switching rate rate but are in opposite phase. One half of a cycle does not count as a fully cycle. Think AC waveform. Thanks for watching.
@@razenby there is no sound, when i use the microphone directly, i can see the signal level moving up and down. what are the common problems with the 500 series with no sound? someone on one forum suggested it could be the equalizer switch and the temporary fix is to short pin 1 and 3 (always flat). what do you think? thanks for replying promptly. could you share your 500 and 515 schematics?
I have seen 1 or 2 with a broken equalizer switch. That could work. I wouldn't recommend using the switch as it blows the HF driver with way too much HF boost so hot wiring it to centre position is OK providing it is actual open circuit. Check it with a continuity meter to make sure that the signal ends there before you link it out, If you link it out and it is still working then you could have other problems. If you have no sound at all on either channel and the signal and power lights look OK then you likely have a problem with the first input op am chips on the mixer board, The full Bandwidth signal is only passed through 3 chips before being split into the HF and LF compressor channels. See the video on debugging the mixer board. You can usually find blown op amps by checking to see if the 2 output channels on each chip are at 0V. See video, Obviously check the the signal ribbon cable is properly plugged in.
@@jungapo2 If the amplifier has power and you don't have 2 blown drivers then you have likely have a blown op amp chip or the boost switch is broken. Yon can easily test the switch. Just touch the contacts on the boost boost switch at the back and if you hear a buzz from the speaker then likely the mechanism inside has switch has failed failed. The wiper contact drops off. Remove the switch and glue it back on. If not the switch then see the video on checking op amp chips in the mixer board, You can do it with a DVM.
yes the actual value is not too critical but 1 mH works best with the LNK302. The bournes ones aren't great. where are you in the world ?- I have load of the upgrades conductors. You must also change the 302,
