Bally Alpha Sound?

[cobra617]

Folks,
New Alpha M9000 owner here. I don't really know much about the Alpha platform. I have a question regarding the sound. The cabinet I have has 3 speakers. Two above the display and a larger one in the belly.
Only the right top speaker works. I've swapped the rca inputs from the CPU into the soundboard and still only the right speaker worked. (This tells me that the CPU is outputting 2 channels and that the 3.5mm headphone jack to RCA cable is working)


Next, I moved the speaker wires from the right speaker to the left and then the left speaker worked. (So I know that the speaker is good)


Before I look for a replacement soundboard or I attempt to repair my soundboard (I was going to cut out the existing amp chip and solder in a new one), I want to verify that all speakers should be working. I've attached a picture of my soundboard. I can't seem to be able to clearly read the part number (to look for a replacement if I need to.....It is either 20147, 2B147 or 28147)


Thanks.

[cobra617]

Folks,
I realized my original post may have been rambling a bit.


Basically, I am just looking to find out if all 3 speakers are indeed supposed to be working. I don't want to get into trying to "repair" the sound board if it was intended to only have one functioning speaker.


I was testing around a bit and found the the left channel of the sound board is not working. (Unless Bally intentionally did this).
So the right channel works and drives the right upper speaker. I found that the left speaker is connected in series with the belly speaker. Since the left channel isn't working, no sound from those 2 speakers.


Thanks.

[777sizzler]

Cobra,  this is actually a good question.  To my knowelege all three should work.  I do still have a couple m-9000's alpha here and will look into this.  I would think it may still lay in the sound driver board.  As soon as I can dig one out -will chk. or another member may chime in.  (my stuff is burried).

[cobra617]

Thanks very much. It is definitely the sound board. I was just curious if Bally was purposely doing this. Since both RCA connectors coming from the CPU have output, I doubt it.


I'll post a WTB on the classifieds to see if I should buy a sound board. If they are too pricey, I'll grab a cheap 20W amp and plug it in to the switched outlet. I'll then have to cut the speaker wire from the connector.

[cobra617]

It ended up being a bad 6.5" belly speaker. Since that speaker and the left are wired in series, neither would work. I ordered a new speaker, and temporarily connected the positive and negative in the belly and now I have stereo sound. Yay.