OutRun: Sound Amp Input Voltage Question

gzsfrk

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Hello arcade repair gurus!

I'm continuing my efforts to get my OutRun Upright Deluxe fully operational. The primary outstanding issue is the audio, which was completely non-functional when I picked it up. To that end, I received a sound amp (Sega part #: 839-0035) in the mail today, fairly confident that it would be the solution to my sound woes (since the cabinet I bought didn't even have a sound amp in it when I picked it up). Keep in mind that I have already jerry-rigged an ugly little connector from the audio-out on the PCB to some computer speakers and verified that I am indeed getting an audio signal.

Unfortunately, after plugging the sound amp in (with all connectors facing the right direction), I still didn't get any sound coming out of the speakers. It's not that the speakers are bad either, as I hooked my kludgy spliced connector up to the wires going to the cabinet's speakers and still didn't get any audio except for a faint buzzing. So I pulled out the sound amp and started tracing wires. As far as I can tell, the power is coming in to the sound amp through the solid grey and solid light blue wires (in my cabinet, at least) in the 8-pin connector harness which also contains the three wires which go to the volume potentiometer. So when I take a DC voltage read on the grey/light blue wires with my DMM, it's only showing 0.16V, which I'm fairly sure is not what the sound amp is looking for. Thus, I suspect there's a problem somewhere in the power supply chain that's not giving the sound amp all the juice it needs.

If that's the case, then one work-around (short of ponying up the cash to buy a replacement power supply) would be to know what the input voltage is supposed to be and then simply install a DC adapter in the cabinet which can provide the requisite volts/amps and wire them into the sound amp.

So I guess my question is two fold:

1. Am I on the right track with diagnosing the problem so far (e.g. Am I, in fact, looking at the correct wires for input voltage)?

2. And if so, does anyone know what the voltage coming in to the sound amp should be? Or alternately, if no one knows off the top of their head, would someone mind taking a reading in their own OutRun, Afterburner, Hang-on, Thunderblade, etc. cab?

For reference, the parts list in the OutRun Owner's Manual refers to 839-0035 as "PWR AMP DC 12V 10W". So if that's the case, I suspect it's looking for a 12V input. However, I don't want to assume anything and blow up the sound amp. That, and I also can't be sure which wire is supposed to be negative and which positive, as even though I'm able to read 0.16V coming off the wires, I can't be sure that the polarity is correct given that there's obviously some other problems going on there.

Thanks much for any help or advice offered!


- m@
 
As far as I can tell, the power is coming in to the sound amp through the solid grey and solid light blue wires (in my cabinet, at least) in the 8-pin connector harness which also contains the three wires which go to the volume potentiometer. So when I take a DC voltage read on the grey/light blue wires with my DMM, it's only showing 0.16V, which I'm fairly sure is not what the sound amp is looking for. Thus, I suspect there's a problem somewhere in the power supply chain that's not giving the sound amp all the juice it needs.

So I guess my question is two fold:

1. Am I on the right track with diagnosing the problem so far (e.g. Am I, in fact, looking at the correct wires for input voltage)?

2. And if so, does anyone know what the voltage coming in to the sound amp should be? Or alternately, if no one knows off the top of their head, would someone mind taking a reading in their own OutRun, Afterburner, Hang-on, Thunderblade, etc. cab?

The power input to the amp is indeed on a blue & grey wire, in an 8-pin connector. HOWEVER, that 8-pin connector does not also house the wires to/from the volume pot. The other wires in that 8-pin connector are the speaker outputs. The pot wires are on the 6-position connector. See attached annotated section of the wiring diagram.

For reference, the blocks on each wire indicate the wire color, per the following codes:

Code:
0 = NO STRIPE (as 2nd digit)
1 = RED
2 = BLUE
3 = YELLOW
4 = GREEN
5 = WHITE
6 = MAROON
7 = ORANGE
8 = BLACK
9 = GRAY
A = PINK
B = LT BLUE
C = BROWN
D = PURPLE
E = LT GREEN

S = small gauge wire
L = large gauge wire
J = jumper wire
 

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The power input to the amp is indeed on a blue & grey wire, in an 8-pin connector. HOWEVER, that 8-pin connector does not also house the wires to/from the volume pot. The other wires in that 8-pin connector are the speaker outputs. The pot wires are on the 6-position connector. See attached annotated section of the wiring diagram.

Man alive, Darren! You're all over my OutRun cab questions. I'm going to have to add a gift for you to my Christmas shopping list. :)
 
Well bull balls... Tried hooking up the external 12V 6A DC adapter in place of the 12V out from the internal PS, but still getting bupkus from the speakers. On the bright side, I refined my kludgy little wiring harness for hooking the PCB's audio out to my computer speakers and I'm now getting both L & R channels, which is a huge improvement over splitting just the R channel across both speakers. (I'm actually getting stereo effects and music now.) So at this point, I think I'm just going to proceed with making the custom audio output solution more formal; need to find a small amp that I can wire into the cabinet's AC and then use it to capture the audio from the PCB and drive the cabinet's speakers. Anyone have any good suggestions on a small amp that's strong enough to drive the 5" (?) speakers in the cabinet, but that won't (any more than necessary) kill the UPS I have the machine hooked into for power protection? Just need something simple that can take two-wire input of any kind and output stereo.

On the downside, I'm still getting the PCM popping and missing sounds. I think the next step will be to remove the boards, re-seat all the chips, and look for small shorts due to solder bridges, leaning caps, etc..

Worst case, I guess I'll just end up in the market for (at the very least) a new top board.
 
While you in there, I recommend adding a sub-woofer. I used a powered PC sub-woofer. IMHO, it really fills out the audio and makes it sound much better. The best signal to grab for it is a seperate "mix" signal used on the sit-down models. Attached are some pics of my mine...

Shown are the add'l audio output header & connector, the sub itself mounted on a shelf in the cabinet, and the seperate volume control for it I wired in (accessable from the coin door).
 

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While you in there, I recommend adding a sub-woofer. I used a powered PC sub-woofer. IMHO, it really fills out the audio and makes it sound much better. The best signal to grab for it is a seperate "mix" signal used on the sit-down models. Attached are some pics of my mine...

Shown are the add'l audio output header & connector, the sub itself mounted on a shelf in the cabinet, and the seperate volume control for it I wired in (accessable from the coin door).

Thanks, Darren! I will definitely do that. I was actually wondering what that unused connector coming off the PCB was for. Figured it was probably something to do with the lights and movement of the sit-down deluxe version.
 
Thanks, Darren! I will definitely do that. I was actually wondering what that unused connector coming off the PCB was for. Figured it was probably something to do with the lights and movement of the sit-down deluxe version.

That particular header is only audio. The other 4 pins are unamplified L & R audio for external jacks on the sit-down model.

The brake light is actually on a different connector. I briefly thought about hooking it up to a lighted sign on top of the game that said "I'm a pu**y" whenever the player hit the brake...
 
HAHAHA!!! BRILLIANT!!!

tumblr_m5cd6slRc51r6rdclo1_400.jpg
 
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