Hey, I have a JL 300/4 with a broken channel, that broke last week. It looks like what's in red is shorted , and have a couple of resistors to replace too that have gone with it.
But I can't find what's in red and can't find anything. I can find what the tops transistor are but this one I have no idea.
Does anyone have any clue?
Thanks in advance
But I can't find what's in red and can't find anything. I can find what the tops transistor are but this one I have no idea.
Does anyone have any clue?
Thanks in advance
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3 legs suggests transistor.
Unlikely to be double diode.
Maybe the number/code on transistor on good channel might help ?
Unlikely to be double diode.
Maybe the number/code on transistor on good channel might help ?
The transistor is likely a BC846B. There is a MMBT2222 that is marked 1B but the majority of the SMD transistors and diodes are more likely to be the Rohm parts than the parts associated with US manufacturers.
It's look like the BC846B is obsolete and no longer sold at digikey, however, I found those at mouser witch look fine.
https://www.mouser.ca/ProductDetail/Diotec-Semiconductor/BC846B?qs=OlC7AqGiEDkE/6m7W8uUrg==
Is there any other way to know if it's the same on the board? What will happen if it's not the correct transistor that's going there ? Sorry if it's a stupid question, it's just a hobby for me. i'm still having a lot to learn and most of the time i can just know what parts it is with the marking on it.
https://www.mouser.ca/ProductDetail/Diotec-Semiconductor/BC846B?qs=OlC7AqGiEDkE/6m7W8uUrg==
Is there any other way to know if it's the same on the board? What will happen if it's not the correct transistor that's going there ? Sorry if it's a stupid question, it's just a hobby for me. i'm still having a lot to learn and most of the time i can just know what parts it is with the marking on it.
Sometimes, you just have to make an educated guess.
If it's not the right part, it may not be reliable or may not work at all.
Octopart shows plenty of options, including DK.
https://octopart.com/search?q=BC846B¤cy=USD&specs=0
If it's not the right part, it may not be reliable or may not work at all.
Octopart shows plenty of options, including DK.
https://octopart.com/search?q=BC846B¤cy=USD&specs=0
You have a LOT of burned parts on that board. Use the other boards as a reference for the values.
If possible, find a donor amp to take a board from.
If possible, find a donor amp to take a board from.
Yeah I know that's what I've done. Everything is in my cart and waiting to be ordered.
I will wait till tomorrow because my amp is only 3 months out of warranty and got news tonight from my local authorized dealer and told me jl may take it back for warranty repair, even if its out of warranty, but I will have definitive answer tomorrow.
Anyway that's what I found to be defective.
Brown =Bad
Green Good but burned, will be replaced
Blue = Out of spec
If I can't save this board I will see what's less expensive to do.
I will wait till tomorrow because my amp is only 3 months out of warranty and got news tonight from my local authorized dealer and told me jl may take it back for warranty repair, even if its out of warranty, but I will have definitive answer tomorrow.
Anyway that's what I found to be defective.
Brown =Bad
Green Good but burned, will be replaced
Blue = Out of spec
If I can't save this board I will see what's less expensive to do.
I just realized that I have some defective leds on other board too.
Have only 3 leds working for all 4 board, 2 on the defective one and one on an other one.
That's strange, idk why they all dead, but doesn't prevent the amp from working.
Have only 3 leds working for all 4 board, 2 on the defective one and one on an other one.
That's strange, idk why they all dead, but doesn't prevent the amp from working.
It's possible but it's more likely that the large 47k ohm resistors have bad solder connections.
Last amp I had with these daughter cards (a 500/5) I had to replace the cards cause they were too far gone. No idea what causes them to fail because nothing had gone bad in the output stage, seems the drivers cards just went bad on their own. Maybe they have overheating issues or something.
Yeah, same for me. Nothing in the output stage. They may have a design issue or something. I don't even drive it hard, it only runs my jl c7 tweeter, so only a couple of watts and has a lot of air flow near the amp. It just died on their own.
I wonder if it was the 47 k ohm resistor that had caused the other resistors to burn, because now it was O.L but when I tested it first it was like 10k ohm, which is too low and maybe has caused too much current to pass into the other resistors.
I wonder if it was the 47 k ohm resistor that had caused the other resistors to burn, because now it was O.L but when I tested it first it was like 10k ohm, which is too low and maybe has caused too much current to pass into the other resistors.
After replacing all the resistors and transistors I mentioned above,I realize that there still too much current passing through the same resistor so I looked what I missed, and it's look like the first transistor up left was dead shorted.
So I ordered some BC850B and hopefully this time it will be good.
So I ordered some BC850B and hopefully this time it will be good.
Replace the one under it, as well. They are part of a differential amplifier and need to be closely matched.
After replacing all 3 transitsors up left, it still didn't work, but I found those 2 thing to become crazy hot. Do you think they are broken? With my multimeter they react the same as the other 3 board so, I'm not sure.
And in the broken channel with the amp on, it goes from 0 to 5 Dc volts and not stable and when i remove the remote wire it goes straight to 1.5V and slowly goes back to 0 volts in few minutes.
And in the broken channel with the amp on, it goes from 0 to 5 Dc volts and not stable and when i remove the remote wire it goes straight to 1.5V and slowly goes back to 0 volts in few minutes.
