The image attached is the circuit that I found. Could anyone venture a guess as to what this might do based on the components and design? My guess is that it's some type of audio signal modulator, given the 1/8th audio jack ports and potentiometers.


•The board has four 1/8th audio jack ports, two are larger than the rest and have "N" and "M" stamped on them.

•It has one common power input used by most laptop chargers.

•It has one pushbutton switch.

•It has two 85k potentiometers.

•It has one small port on the side with two leads, probably relating to power input or output.

•It has a TDA7360 Audio Amplifier chip, a BUK573 MOSFET, a HCF4066 Quad Bilateral Switch, a MC14013B Dual Type D Flip-Flop, a LF347 Op-Amp (TI datasheet here).

Numbers: IS1, V2.1 REV 5A- Printed on the PCB

323276-004 REV B 5356 ASSEMBLED IN MEXICO- A label on the PCB

9544- Printed on bottom of PCB

That's all the information I have for now. If you think you know what it is but need more information, I'll attempt to disassemble the metal heatsink/housing to get a better look at the bottom. There are some amall logic chips visible on the obscured side.

Photos: The Board 1/8th Ports and Label

EDIT: It has been suggested that I add a picture of the bottom of the board. Here it is.

Back of Board

  • 2
    \$\begingroup\$ It's look like an amplifier with tone control and volume control... The only active component I'm seeing on this board is the power ic. What is the part number of that ic? \$\endgroup\$ Commented Mar 1, 2016 at 1:39
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    \$\begingroup\$ If you'd like your question to be well-recieved here, you should trace out the circuit as much as you can and enter it into the schematic editor. Since it looks to be a single-sided board that should not be terribly difficult. Switch looks to be a pushbutton, not a toggle. \$\endgroup\$
    – Ecnerwal
    Commented Mar 1, 2016 at 2:42
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    \$\begingroup\$ It may have some surface-mount parts on the bottom. but it's a single-sided board - meaning the copper is only on the side away from the photo - thus all the jumper wires. These are generally easier to trace the circuit on than a double-sided board (and when you step up to additional layers, it's not really something that you can do by visual inspection anymore.) \$\endgroup\$
    – Ecnerwal
    Commented Mar 1, 2016 at 2:55
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    \$\begingroup\$ @htownclyde those "more complex IC chips" are far more useful to us if you want some actual answers. I suggest that you edit and show more relevant photos in your question. \$\endgroup\$
    – pipe
    Commented Mar 1, 2016 at 8:19
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    \$\begingroup\$ We could really do with the other side of the board - although it looks like it's really two boards attached together by standoffs? Can you separate them nondestructively? \$\endgroup\$
    – pjc50
    Commented Mar 1, 2016 at 9:27

2 Answers 2


It's a JBL Amp used for augmenting output from a low power music player See http://www.apexjr.com/JBL12.htm


Looks like the amp board out of a subwoofer/satellite "powered speaker" setup, generically; possibly "computer speakers" possibly "home theater"

Usually (but not always) built into the subwoofer box.


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