VIDEO OF ISSUE:YouTube YouTube
Hi,
I am trying to repair my good old JL 1000/1 Class D subwoofer amp. Issue is, it randomly stopped working so I no longer had subwoofer output in my car. Opened trunk and saw, Solid Green power light was on but also the Solid Yellow low ohm light. My Dual JLW6’s subs are 4ohm load and I tested other ways so definitely not the issue.
First, I opened it up and found a few bad output transistors Fairchild SSP45N20B. So, I replaced all 8 output MOSFETS and also all 24 IR3707 Power supply MOSFETS with brand new same batch/make/model as original.
As for the four bridge rectifiers I could only find the SF1604G common cathode so I replaced those 2 but I could not find the SF1606GA common anode version, so I had to put back the used originals. They still worked but I need help finding a suitable replacement for the SF1606GA common anode because the legs are a mess from me removing, like I said I could only find new SF1604G common cathode one for the bridge).
Anyway, so after I replaced all output and power supply FETS and powered up, the same exact output MOSFETS got shorted out again. Powering with lower amp and voltage, the four output fets (#5-#8 from the edge of the board) that seem to always blow got really warm and also the one driver board behind it got hot, (the inner one), the outer driver board stayed totally cold. If you can see in my video it looks like the power supply section is ok, shows the 10 volts I put in and a square wave but that is where my knowledge ends.
Can someone please help me out with the output section that keeps blowing? What should I test or do next? 😕 Any questions/comments welcome. (Watching the video will help explain the problem by seeing it, only 7 minutes long)
I really appreciate any help, thanks in advance!!!!
Regards,
Rob
VIDEO OF ISSUE:YouTube YouTube
Hi,
I am trying to repair my good old JL 1000/1 Class D subwoofer amp. Issue is, it randomly stopped working so I no longer had subwoofer output in my car. Opened trunk and saw, Solid Green power light was on but also the Solid Yellow low ohm light. My Dual JLW6’s subs are 4ohm load and I tested other ways so definitely not the issue.
First, I opened it up and found a few bad output transistors Fairchild SSP45N20B. So, I replaced all 8 output MOSFETS and also all 24 IR3707 Power supply MOSFETS with brand new same batch/make/model as original.
As for the four bridge rectifiers I could only find the SF1604G common cathode so I replaced those 2 but I could not find the SF1606GA common anode version, so I had to put back the used originals. They still worked but I need help finding a suitable replacement for the SF1606GA common anode because the legs are a mess from me removing, like I said I could only find new SF1604G common cathode one for the bridge).
Anyway, so after I replaced all output and power supply FETS and powered up, the same exact output MOSFETS got shorted out again. Powering with lower amp and voltage, the four output fets (#5-#8 from the edge of the board) that seem to always blow got really warm and also the one driver board behind it got hot, (the inner one), the outer driver board stayed totally cold. If you can see in my video it looks like the power supply section is ok, shows the 10 volts I put in and a square wave but that is where my knowledge ends.
Can someone please help me out with the output section that keeps blowing? What should I test or do next? 😕 Any questions/comments welcome. (Watching the video will help explain the problem by seeing it, only 7 minutes long)
I really appreciate any help, thanks in advance!!!!
Regards,
Rob
VIDEO OF ISSUE:YouTube YouTube
Last edited:
I don't do video for repairs.
The amp will produce drive pulses for the outputs for about 15 seconds if you apply remote for a second or so, then remove it.
Post waveforms for the four FETs in the group that are failing. 2 waveforms since they are driven in 2 groups. Confirm that the gate resistors are within tolerance.
The amp will produce drive pulses for the outputs for about 15 seconds if you apply remote for a second or so, then remove it.
Post waveforms for the four FETs in the group that are failing. 2 waveforms since they are driven in 2 groups. Confirm that the gate resistors are within tolerance.
Crap ok. I thought me providing a video of my test's would be the most helpful in trying to explain my issue.
Rob, I watched the video and seen that you have a bench with real electronics equipment, so you probably have a basic understanding of electronics or better. Perry is the expert and can guide you though it (you should check out his web site, and his repair guide is worth it if you like to fix amps). That being said, you should first go watch some videos that Sam made (he is Barevids on youtube, search that). He has done a couple videos on repairing the 1000/1 and the 500/1 that might help you (be sure to skim though the posted live streams, I think one is in that group), or at least help you test and post good info. Check it out.
Ok cool thanks a lot!! I'll check out those videos you mentioned. I've been combing through the entire internet for weeks now watching every single amplifier repair loll. I hate to give up on this amp but worse case scenario it turns into a great electronics learning project.
Perry,
I just tested the gate resistors all are close to 5ohm.
I had already removed the 4 inner output fets that appreared blown in circuit, but only two of the four were blown when removed.
Not sure if you do pictures but I'll post them just incase below. Unfourntely I don't know much about any further waveforms after getting a good square wave on the power supply side. Right now I have a board with 4 bride rectifiers removed, and the 4 output gets next to them out. I put a probe on the case one of the 4 remaning outputs fets but not sure what I am looking at. Can I do what you asking with the bridge and four output fets out?
THANKS!
I've never tried this without the rectifiers.
You should at least get drive on the low-side FETs (leg 3 connected to ground). If you apply then remove remote, do you get low-side gate drive?
Set your scope to 5us and 5v/div.
You should at least get drive on the low-side FETs (leg 3 connected to ground). If you apply then remove remote, do you get low-side gate drive?
Set your scope to 5us and 5v/div.
Hi Perry,
First let me thank you for your help, I know you are one of or the most experienced with everything. And I think you havea lot of specific experiience with the JL 1000/1 & 500/1 V1's. I have read all of your amplifier repair manual (the green background one, I even have some pages posted on my wall for reference way before I even started this thread.) And watched all bareskin's videos.
Honestly I'm a little lost and stuck here, pls excuse my ignorance. I set and attached the scope to the third leg on each of the two mosfets (the first two on the board) which I believe is the low side. What I am suppose to see here? (below are 2 pic's of what I did)
On a separate note, another stuck point about the rectifiers. I want to put them back in to move this along but I need to order two of them. There are 4 rectifiers total and I was only able to get the two SF1606G which is the Positive Common Cathode (Suffix "G”) version of this Rectifier but I also need two of SF1606GA which is the Negative Common Anode (Suffix "GA") version of this Rectifier by “Taiwan Semiconductor Company, Ltd”. but it is not available anywhere.
Would you be able to recommend a more available part that is suitable to replace two of the SF1606GA Negative Common Anode on the JL 1000v1?
THANKS!,
Rob
First let me thank you for your help, I know you are one of or the most experienced with everything. And I think you havea lot of specific experiience with the JL 1000/1 & 500/1 V1's. I have read all of your amplifier repair manual (the green background one, I even have some pages posted on my wall for reference way before I even started this thread.) And watched all bareskin's videos.
Honestly I'm a little lost and stuck here, pls excuse my ignorance. I set and attached the scope to the third leg on each of the two mosfets (the first two on the board) which I believe is the low side. What I am suppose to see here? (below are 2 pic's of what I did)
On a separate note, another stuck point about the rectifiers. I want to put them back in to move this along but I need to order two of them. There are 4 rectifiers total and I was only able to get the two SF1606G which is the Positive Common Cathode (Suffix "G”) version of this Rectifier but I also need two of SF1606GA which is the Negative Common Anode (Suffix "GA") version of this Rectifier by “Taiwan Semiconductor Company, Ltd”. but it is not available anywhere.
Would you be able to recommend a more available part that is suitable to replace two of the SF1606GA Negative Common Anode on the JL 1000v1?
THANKS!,
Rob
I don't have a source for the rectifiers.
The gate leg is where you need to look for signal. It's leg 1.
The gate leg is where you need to look for signal. It's leg 1.
Just in general, when trying to replace a rectifier with a different replacement part are there any specs that absolutely need to be exact to the original, or anything close should work? Because I cant find anything with the exact same specs.
It needs to be rated as ultra-fast. Slower rectifiers will overheat and fail. The voltage is much higher than it would be for amps of similar power. That's due to the high turns ratio they use so you need a high voltage rectifier. The current rating is also important.
Are the legs broken?
Are the legs broken?
Yup the legs are only a few millimeters long on one and the other one is not much better. I already reused them once by soldering legs and small wires but it’s very difficult, messy & probably not very sturdy.
Ok I’ll look for Ultra Fast. I think the stock ones are rated 300v so I will look for at least that. Thank you.
Ok I’ll look for Ultra Fast. I think the stock ones are rated 300v so I will look for at least that. Thank you.
The originals are 400v.
Look at the voltage on the input to the rectifiers with your scope. I think it's very near 400v.
Look at the voltage on the input to the rectifiers with your scope. I think it's very near 400v.
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