How to wire a Namco audio amp?

[b3dr0ck]

I've got an arcade cabinet with a blown audio amp.

I have this audio amp, that I believe is a Namco audio amp pull. (see pic)
2CH AMP PCB
V102962103

Does anyone know how to wire it, and be willing to give me instructions, or a link (I can find no docs on this).

Thanks,

[Kevin Mullins]

Damn... I used to have a pinout drawing for those, I have several and use them all the time.
I'd have to dig some more for it or draw up another. (but would have to be this evening)

But - J202 is the input, J201 is power, J203 is the output

Or you can try to figure it out from the datasheet.
http://www.datasheetcatalog.org/datasheet/sanyo/ds_pdf_e/LA4705.pdf

[b3dr0ck]

I can perceive nothing from the datasheet.

J202 - input, there are 5 pins there.  I'd think audio input would have 2 or 3, so I don't know what to do there.

J201 - is power, that makes sense, pins 1-3, not sure what voltage connects and ground.  Ground middle?

J203 - 4 pins there, makes sense, 2 channels, right and left

I can't see the bottom of the PCB, I could take it off the plate, not sure it'd help.

[Kevin Mullins]

Took a quick look at one today... try this.

PIN NUMBERS ARE AS THEY ARE MARKED ON THE PCB 1, 2, 3, etc
(not left to right or anything like that)

J201- Power Input
1- 12v DC (up to 18v)
2- Ground
3- N/A

J202 - Audio Input
1 - Input 1 +
2 - Ground 1 -
3 - Input 2 +
4 - Ground 2 -
5 - Ground (extra I guess, it's tied to pin 4)

J203 - Audio Output
1 - Out 1 +
2 - Out 1 -
3 - Out 2 -
4 - Out 2 +

[Marsupial]

sometimes it doesn't make sense, but their connectors are made different just for the purpose of making life easier for the techs that will connect those. Different number of pins = low brainer.

[Kevin Mullins]

Yeah, that makes sense.
Same numbers of pins + same style connector = der moment in the making.

[b3dr0ck]

Thanks!

I wired it up, very quickly just to see if it works, and it does.  I only wired one channel, but the speakers in the top of the cab. are on one channel anyway.

Sound quality isn't great, but the wiring is a little ridiculous, I'll tidy it up later, I just wanted to test it out.

Thanks again, that saved me a few bucks, and gave me some more experience.

[Kevin Mullins]

Cool...glad you got to try it out.

Since you have a mono speaker setup in the cab, half the amp is trying to drive both speakers at a higher resistance. (probably wired in series)
You might try splitting the speakers to have each of their own output from the amp, and split the input going to the amp to run both sides.
Unless you wire up a true stereo input, then just split the speakers and wire it up full stereo.

And don't forget that those two potentiometers on that little pcb are volume controls as well. So I usually turn those down, set whatever my input is to max volume, then set those two pots at a reasonable level as to not have a lot of distortion and whatnot. That way you don't have to mess with them again, just use whatever your regular volume control is.

Takes some playing with, but you have the right idea now at least.