My Speaker has no power,it doesn't start

[mars]

I have a midialnd MLI 480 computer speaker.

In a hot day last summer, after i turned the bass and volume almost to
full and played game for 30 minute, I turned the speaker off.
The next day when i turned on the speaker, it was competely dead.
It had no power,led did not light up.

So i opened the speaker,I discovered the capacitor next to the
amplifier IC was bulged. That capacitor was 16V 4700uF,the largest
capacitor on the circuit.
I also did the viusal check and tested all of the resistors, diodes
and transistors on the circuit using multimeter, every thing was fine.
I did not test all of the capacitors since i don't have the
oscilloscope
The speaker still has no power and no led light after i repalaced the
capacitor.

The speaker uses an AC adapter, and the label on the ac adapter said
it has 12V AC output.
I checked the adapter, it had 13.2V AC.And i also checked the two
terminals of the switch. it has 17.69DC.


I guess the amplifier is the source of problem
The amplifier IC is Philips TDA1519A
http://www.semiconductors.philips.com/pip/TDA1519A.html

Is there any test i can perform to find out the ic is bad?
Do i have to replace the IC?
Anything else can cause no power for the speaker?
Any suggestion!
Thanks!

 

[Ken Weitzel]

I have a midialnd MLI 480 computer speaker.

In a hot day last summer, after i turned the bass and volume almost to
full and played game for 30 minute, I turned the speaker off.
The next day when i turned on the speaker, it was competely dead.
It had no power,led did not light up.

So i opened the speaker,I discovered the capacitor next to the
amplifier IC was bulged. That capacitor was 16V 4700uF,the largest
capacitor on the circuit.
I also did the viusal check and tested all of the resistors, diodes
and transistors on the circuit using multimeter, every thing was fine.
I did not test all of the capacitors since i don't have the
oscilloscope
The speaker still has no power and no led light after i repalaced the
capacitor.

The speaker uses an AC adapter, and the label on the ac adapter said
it has 12V AC output.
I checked the adapter, it had 13.2V AC.And i also checked the two
terminals of the switch. it has 17.69DC.


I guess the amplifier is the source of problem
The amplifier IC is Philips TDA1519A
http://www.semiconductors.philips.com/pip/TDA1519A.html

Is there any test i can perform to find out the ic is bad?
Do i have to replace the IC?
Anything else can cause no power for the speaker?
Any suggestion!
Thanks!

Sounds like the switch is open to me

Take care.

Ken

 

[Sofie]

mars:
You posted this very same question on rec.audio.tech 4 days ago and
have received a couple of very good repair suggestions....... have you
acted upon the suggestions? ... you really should post your reply to those
suggestions on that newsgroup ?