Amplified Mini Speaker Modifications

Thread Starter

mikkut

Joined Jul 8, 2021
3
Hi All,

I have an analog amplified mini speaker that I would like to make some modifications to:

The amplified mini speaker as is out of the box:
-There is an internal battery that is charged when connected via micro USB . The speaker cannot operate when the battery is charging
-There is a push button on/off switch
-analog audio in is through a 3.5mm male jack (not through USB port)

What I would like to end up with:
-eliminate the battery and have it powered via hard wire to a DC power source (can be a separate wire, does not need to utilize existing micro USB port)
-eliminate the power switch so that is simply on when power is supplied and off when power is disconnected. I tried disconnecting the existing battery and connecting to a DC power supply and the speaker worked fine BUT it still requires turning on the power switch. And when the power is disconnected it appears the power switch re-sets so turning on the power switch is required every time power is connected.
INTSUN-CircutBoard-01.jpg
No changes needed on the audio in and audio out.

Thanks!!
 

kaindub

Joined Oct 28, 2019
92
The power on switch is what is called a soft switch. It’s an input to a controller on the board. The controller enables an output which turns on a “ power transistor”.
It may be as simple as bypassing the “power transistor”
 

mikewax

Joined Apr 11, 2016
181
i assume the control input is just a high-z input line that is pulled up with a R and is pulled to ground when u press the button, so it may be possible to just put a capacitor across the button. So when the control chip is powered up the control input will go low for long enough to trigger. Then put a bleed resistor across the cap.
 
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