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Electronics => Repair => Topic started by: mjrpainless on October 04, 2019, 11:48:05 pm

Title: JBL E250P subwoofer repair
Post by: mjrpainless on October 04, 2019, 11:48:05 pm

Hey all,

I have a subwoofer that I'm trying to troubleshoot.The driver was blown. I measured some AC noise on the output with the unit powered on, and no input connected.

I'm usually pretty good at these things, but this thing has been a pain. Any help, or pointers would be greatly appreciated.

I am beating my head against the wall. And am looking for some guidance. I have posted the service manual. 

Title: Re: JBL E250P subwoofer repair
Post by: don.r on October 05, 2019, 12:40:33 am

Test output transistors for shorts. I'm working on a bench dmm that has a shorted op amp (44K Vdd to Vss) and that was causing a big AC ripple on the power rails.