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!

[cyberdyne82]

Bonjour, Je me présente rapidement dans un premier temps. J'ai une petite quarantaine d'année, developpeur web. Je suis un grand fan de musique et de film en tout genre.

Je possède un enssemble home cinéma JBL Northridge E80 depuis plus de 10 ans. Depuis quelques semaines, mon caisson basse le ES150P a son système de stanby qui bug. En effet il est censé se mettre en veille au bout de 10min plus ou moins. Maintenant, il n'y a plus les 10 minutes donc lorsque je regarde un film, écoute de la musique il s'allume et se met en standby toutes les secondes presque. Lorsque je met de la musique ou un film avec des basses il ne s'éteint pas et le son est excellent comme au début.
Je ne suis malheureusement pas du tout connaisseur en électronique, je n'ai pas de matériel également et JBL ne peut rien faire pour moi car les pièces d'origines de rechange n'existent tout simplement plus.
Je suis presque sur que ce n'est pas grand chose. Si jamais quelqu'un habite sur Paris et peut m'aider ça serait très gentil.


Hello,

Let me introduce myself briefly. I am in my early forties, a web developer. I am a big fan of music and all kinds of movies.

I have owned a JBL Northridge E80 home theater system for over 10 years. For the past few weeks, my subwoofer, the ES150P, has been experiencing a standby system issue. It is supposed to go into standby mode after about 10 minutes. Now, it no longer waits 10 minutes, so when I watch a movie or listen to music, it turns on and goes into standby almost every second. When I play music or a movie with bass, it doesn't turn off and the sound is excellent as it was in the beginning.

Unfortunately, I am not knowledgeable about electronics at all, and I also do not have the necessary equipment. JBL cannot help me because the original replacement parts simply no longer exist. I am almost sure it is not a big issue. If anyone lives in Paris and can help me, it would be very kind.

[marx30]

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!

Hello proditaki. I have exactly the same problem
Could you tell me which caps did you replaced? They are on preamp board or little board near to power plug?

[marx30]

Bonjour, Je me présente rapidement dans un premier temps. J'ai une petite quarantaine d'année, developpeur web. Je suis un grand fan de musique et de film en tout genre.

Je possède un enssemble home cinéma JBL Northridge E80 depuis plus de 10 ans. Depuis quelques semaines, mon caisson basse le ES150P a son système de stanby qui bug. En effet il est censé se mettre en veille au bout de 10min plus ou moins. Maintenant, il n'y a plus les 10 minutes donc lorsque je regarde un film, écoute de la musique il s'allume et se met en standby toutes les secondes presque. Lorsque je met de la musique ou un film avec des basses il ne s'éteint pas et le son est excellent comme au début.
Je ne suis malheureusement pas du tout connaisseur en électronique, je n'ai pas de matériel également et JBL ne peut rien faire pour moi car les pièces d'origines de rechange n'existent tout simplement plus.
Je suis presque sur que ce n'est pas grand chose. Si jamais quelqu'un habite sur Paris et peut m'aider ça serait très gentil.


Hello,

Let me introduce myself briefly. I am in my early forties, a web developer. I am a big fan of music and all kinds of movies.

I have owned a JBL Northridge E80 home theater system for over 10 years. For the past few weeks, my subwoofer, the ES150P, has been experiencing a standby system issue. It is supposed to go into standby mode after about 10 minutes. Now, it no longer waits 10 minutes, so when I watch a movie or listen to music, it turns on and goes into standby almost every second. When I play music or a movie with bass, it doesn't turn off and the sound is excellent as it was in the beginning.

Unfortunately, I am not knowledgeable about electronics at all, and I also do not have the necessary equipment. JBL cannot help me because the original replacement parts simply no longer exist. I am almost sure it is not a big issue. If anyone lives in Paris and can help me, it would be very kind.

It is probably cap 220 uf on preamp board

[kamueone kamue]

MY SOLUTION

Hi to all,

I have expirenced the same Problem. After a while the Sub wanted to AUTO Standby, and gone nuts. Cycled endlessly On and OFF or did not come ON after OFF.

I did not like that AUTO Standby so i disabled it completly.

Just cut one of the legs of the Resistor R142.

The Capacitor does not get any current to fill him self up, and if that does not happen nothing else Triggers. So Always ON. Just unplug when not needed or POWER OFF.



If you need the AUTO OFF Function just replace C131 - Capacitor (220 µF, low leakage) - LOW LEAKAGE EC 220uF 16V ±20% (RoHS)





For those that want to know why this works:

🔬 Technical explanation – RC time constant


The Auto-Off feature in the ES150P works using a standard RC timing circuit (resistor + capacitor), which delays switching based on signal absence. The timing is determined by this formula:

τ=R×C\tau = R \times Cτ=R×C

In this case:

• R142 is the resistor
• C131 is the capacitor (220 µF, low leakage)
• The voltage across C131 slowly changes when no audio signal is present.
• When that voltage crosses a threshold (usually into an op-amp or comparator like U103), the circuit triggers the Auto-Off state.

---

🔁 What happens if you remove R142?

R142 present (e.g., 330 kΩ)	Auto-Off works after ~10 minutes
R142 increased (e.g., 10 MΩ)	Auto-Off takes much longer (30+ mins)
R142 removed (open circuit = ∞ Ω)	No current can charge/discharge C131 → Voltage never reaches trigger level → Auto-Off never happens

In other words, the capacitor never reaches the voltage that tells the circuit to shut off.

---

📘 Verified by Service Manual


The JBL ES150P Service Manual, page 12, says:

Auto-Off Function → Check U103, Q101, Q102, C131, R142

This confirms that R142 and C131 are essential parts of the timing circuit. If you remove R142, you break the circuit — the timing voltage never changes — so the Auto-Off logic can't do its job.



HOPE THIS HELPS