JBL ES-150-P standby issue

[proditaki]

Hello,

I recently bought a faulty JBL ES-150P subwoofer that was completely dead.
After replacing 2 open resistors (R255 and R256) in the DC Power supply the unit started working.

It plays fine. But when it wants to go into standby mode, after 10 minutes, it starts cycling for a while. (see video on youtube)
The noise from the speaker goes away and i'm pretty sure the interval changes and i only hear one relay clicking on the end (light still goes red/green)

After cycling for like 30 secs to a minute it eventually goes into standby. It also wakes up fine when you present an audio signal. (Above also occurs without a source connected to the LFE /Line in)

I'm at a bit of a loss

Datasheet attached.

So far replaced
R255 / R256
C162 / C161
C166 / C167
C134 / C136
U103

So far checked
C168 C169 C170 C171 (ESR good)
C131
C132
C126
U101

Q103
Q102
Q101

[debruina]

Re: JBL ES-150-P standby issue

1. Check C16/C18 ? 10uF np
2. If it has brown glue on the board, remove it

Picture would help

[proditaki]

Re: JBL ES-150-P standby issue

Ok. I took some pictures. I already had it reasembled for testing

[proditaki]

Re: JBL ES-150-P standby issue

1. Check C16/C18 ? 10uF np
2. If it has brown glue on the board, remove it

Picture would help

The ESR on C16 and C17 is fine. i removed them from circuit to test. Well within spec.

[proditaki]

Re: JBL ES-150-P standby issue

Also replaced C18 & C19 but no difference.

[debruina]

Re: JBL ES-150-P standby issue

If it has sound than probably the amp board is Okay. Did you check +15/-15 voltages? manual page 30/31? caps, next i would check the mute circuit.

It's more or less the same amp used in those HK subwoofers. Eventualy they all fail. The glue in you pictures is still white. When it becomes dark it becomes a conductor. Then you get all kind of strange problems. Yours looks still okay

[proditaki]

Re: JBL ES-150-P standby issue

If it has sound than probably the amp board is Okay. Did you check +15/-15 voltages? manual page 30/31? caps, next i would check the mute circuit.

It's more or less the same amp used in those HK subwoofers. Eventualy they all fail. The glue in you pictures is still white. When it becomes dark it becomes a conductor. Then you get all kind of strange problems. Yours looks still okay

Yeah the sound seems fine.
I did check the caps on the +15V lines and replaced some (which were borderline faulty) by new ones (which i checked before replacing) but to no effect.

Id did check the "big" caps on vcc+/- and vbb+/-

so yeah probalby something in the mute circuit.

i already replaced U103 for a brand new opamp (you see it sitting in a socket in the pictures i took because the pcb traces are quite fragile and i didnt want to have to desolder it twice)

i did measurements on Q101, Q103 adn Q102 they seem fine.

[proditaki]

Re: JBL ES-150-P standby issue

Ok i fixed it.
The service manual was rev 0.
In the revision i have they changed a few things and they use a 6v power supply for the mute/standby circuit, which i completely missed because the 15v power supply is still there (obviously, it's just disconnected from that circuit ) .

THe +6V / -6V power supply was more like +4.5 / -7V because of one failed cap. So i replaced them all, it's working fine now. Thanks!