Hello:
I would be grateful if you can help me to repair my JBL ES150 Subwoofer. Few days ago I found that there is no power light and with my little knowledge of electronics I attempted to repair that. After opening I saw that the main fuse and output FETs are toasted!
I replaced the FETs and fuse. Power light came back but orange! Further checked and found that the (DC) +V is coming to speaker line and relay is not engaging to save the speaker.
I have measured voltages of some areas and all of the places, +V is present with respect to GND. Now would you please let me know what and how I can check to make the sub live again!
In the picture red marked points are +V. FETs are okay.
I would be grateful if you can help me to repair my JBL ES150 Subwoofer. Few days ago I found that there is no power light and with my little knowledge of electronics I attempted to repair that. After opening I saw that the main fuse and output FETs are toasted!
I replaced the FETs and fuse. Power light came back but orange! Further checked and found that the (DC) +V is coming to speaker line and relay is not engaging to save the speaker.
I have measured voltages of some areas and all of the places, +V is present with respect to GND. Now would you please let me know what and how I can check to make the sub live again!
In the picture red marked points are +V. FETs are okay.
Attachments
Make sure the op amp is running with a nice square wave output on pin 1. Check the driver transistors, 2k2 resistors and turn off diodes first
Thanks a lot for your time to rely. I checked driver transistors and they are fine in digital meter. I will check op amp and will post updates.
Thanks once again.
:....2k2 resistors and turn off diodes" - can you please let me know a bit detail
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Altenative: keep this junk power module as an antique or for learning stone age class D, and replace by more reliable IRS2092 boards found on ebay.
Thanks a lot Eva for your suggestion.
Hi,
Check and replace Q58,Q68,Q9&Q8
Check Voltage +/-15v
Remove Q1
Check point C3 with DSO F=@140KHz
after working fix Q1
Regards
MANOJ
Thanks MANOJ, I removed the power transistors but not Q1. without power FETs V+ is present at speaker line. I will check osc at C3
Thanks once again.
I was busy with some other issues and have got the time to check.Thanks MANOJ, I removed the power transistors but not Q1. without power FETs V+ is present at speaker line. I will check osc at C3
Thanks once again.
Yesterday I found that the 12V zener diodes (Z4, Z5 and Z6) shorted. Driver transistors are toasted. OP amp voltage was 17V (Pin 4 & 8) when I removed that it is 24V now. Seems that the OP amp also gone.
It's really difficult to find SMD part in my local market. However, trying to arrange them. Will keep you posted.
Z5 and Z6 blown imply almost all output stage is blown.
Z4 blown is different issue, in the sense that, by looking at the schematic, I can't find any chain reaction that can lead to Z4 blown, unless Z4 was the one that blew first, resulting in wrong drive of output stage and all blowing.
Z4 blown is different issue, in the sense that, by looking at the schematic, I can't find any chain reaction that can lead to Z4 blown, unless Z4 was the one that blew first, resulting in wrong drive of output stage and all blowing.
Z5 and Z6 blown imply almost all output stage is blown.
Z4 blown is different issue, in the sense that, by looking at the schematic, I can't find any chain reaction that can lead to Z4 blown, unless Z4 was the one that blew first, resulting in wrong drive of output stage and all blowing.
I replaced output FETs first and later on found than other components were fried as well.
However, I ordered the full amp module and waiting for delivery to Bangladesh.
I will try to rebuild the board until ordered one arrives. Thanks Eva for your reply
Altenative: keep this junk power module as an antique or for learning stone age class D, and replace by more reliable IRS2092 boards found on ebay.
Hello Eve, your post is some years ago and i have the same problem with my amplifier. If i get IRS2092, can i use the switch on the back as before? How do i connect it so everything is like before in functions?
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