Multimedia Lite Schematic

[dbinder]

This is how it's wired into the inline amp

[Tilt]

Can you read the number on the faded one?  I can't make it out from the photo.  If the sounds work correctly in mono why not leave it there?

[dbinder]

It's tough to read so I might be off by a number..


It looks like 60754904A and either hk701/04 or nk704/01.


If that doesn't work let me know.

[Tilt]

From comparing wires on P7 it's a 6075804 harness which is a stereo harness.  Here's the audio diagram again with what you have in your machine highlighted by the red boxes. 

You could try replacing the MML2 board, but I'm not sure if that would help or not.  Maybe the game doesn't support stereo sound?  On the other hand they're pretty cheap, and good to have a spare anyhow.

[Stayouttadabunker]

This is how it's wired into the inline amp

Whenever I see those loops on connectors, I wonder if the company designed something wrong on the circuit board. 

[dbinder]

Exactly. The Speaker A+/- and Speaker B+/- just doesn't add up from the schematic to the amp. The only think I can tell you is that the inline amp is working as it's supposed to and the audio is wonky getting there. That seems to be the big question I have at this point in solving what's going on. I've traced it all the way back to to backplane and I had to stop there because I don't have the correct equipment to test it. I would have to somehow run audio from the molex connector that is already plugged in because there are optics tied to the same plug. If the audio there is out of balance then the only other place is off the MML2 card, which is what I am expecting. I've brought this thing back from the dead and really want it to be minted out for my collection. This is the last piece!

[Stayouttadabunker]

That's good sleuth work dbinder 

Better understanding of the way of how this audio amp works in the IGT's is helpful to everyone here in the future because I'm sure that many have "wonky" sounds coming out of their different machines....the same amp is used in IGT S2000.s, Game King's, I-Games and Visions.

Please give us as much details as possible in what you're finding out.Other than switching to enhanced MPU's from the older 502's to 504 MPU's, there has never really been any solution to the crappy sound we get from these audio amps.

Oh... I've tried the different resistors on the speaker wires as suggested by members but all that really did was overheat the audio amp to the point of burning out on some.

Anyways, on these, they're jumping 4/5 and 1/9 (CHAN A ATTEN and CHAN B ATTEN)
Why would they do that?  Also....what do they mean by "ATTEN?

[dbinder]

I'll be doing more work on it today and try to be as specific as possible.


I've already used 10k pots and it helps but is not the answer. Can I ask, how did you wire the resistors and what values? I've been told use either 10ohm, 22ohm or 47ohm on the plus side of each speaker. That was my next fix.

[Stayouttadabunker]

I have the 47 ohm resistors on the + side of each topbox speaker under heatshrink tubing.

I wonder...does it matter which way the resistor is pointing and if I should remove the heatshrink? 

[dbinder]

I don't believe polarity is a concern for resistors. Did that help your problem?

[dbinder]

From comparing wires on P7 it's a 6075804 harness which is a stereo harness.  Here's the audio diagram again with what you have in your machine highlighted by the red boxes. 

You could try replacing the MML2 board, but I'm not sure if that would help or not.  Maybe the game doesn't support stereo sound?  On the other hand they're pretty cheap, and good to have a spare anyhow.

This is great! So now the question, why would the inputs to the amp in the top box be jumped like that?


Furthermore, why is there a difference in audio level from the left to the right channels before it gets to the amp?

[Tilt]

The jumper wires on P7 are used to select the level of attenuation to the audio signals at the input to the amplifier. There are two options depending on how the jumpers are wired, either 19:1 or 4:1.  Your harness is wired for 19:1.  I believe they have these options so they can properly match the incoming audio levels for the various machines these amplifiers are used in.   Even with the S2000 you can have different sources.  On a standard S2000 the audio signal is processed by the MPU (and MML2 board too if used) and fed to the amplifier.  In a S2000 Vision machine the audio comes from the topbox computer, not the MPU/MML2 board.

I have had a s2000 that had a 4:1 harness in it and it would blast you out of the room even with the volume on the lowest setting.  Repining the jumper wires on P7 resolved that issue.

I wouldn't expect to see any significant differences in the channel audio levels.

[dbinder]

That's sort of what I thought. I do need to get the levels down and at the same time not get the AC noise in the audio. The stereo/mono reel stop sound thing is what's really baffling me.

[Tilt]

I'm still a little confused as to the real problem.  When in stereo you say you can't hear the reel stops, got that, but is the entire channel missing, meaning that you only get sound out of one of the top speakers? 

[dbinder]

It's weird because I hear the medley while the reels spin but I don't hear the Orange or red seven or Tabasco symbol when it hits on the payline in reel 1 or 1&2 or all three. When the machine is in stereo, It's like they don't exist. Medley plays no problem, just no "woo" sounds. (You get it if you know the game). If I listen to the sounds in the I/O setting I hear the sounds whether it's in stereo or mono. If it's in mono, I hear them in game play.

[Tilt]

When in stereo mode is the reel spin melody coming from just one of the upper speakers or both?

When in mono are both sides playing the same melody and stop sounds?

[dbinder]

When in stereo mode. I hear the medley in both speakers.


When in mono, same medley and stop sounds are playing in both speakers.

[Tilt]

OK.  There's some audio mixing and switching that takes place on the MML2 board.  I'd replace it and see it that fixes the problem. 

[dbinder]

The jumper wires on P7 are used to select the level of attenuation to the audio signals at the input to the amplifier. There are two options depending on how the jumpers are wired, either 19:1 or 4:1.  Your harness is wired for 19:1.  I believe they have these options so they can properly match the incoming audio levels for the various machines these amplifiers are used in.   Even with the S2000 you can have different sources.  On a standard S2000 the audio signal is processed by the MPU (and MML2 board too if used) and fed to the amplifier.  In a S2000 Vision machine the audio comes from the topbox computer, not the MPU/MML2 board.

I have had a s2000 that had a 4:1 harness in it and it would blast you out of the room even with the volume on the lowest setting.  Repining the jumper wires on P7 resolved that issue.

I wouldn't expect to see any significant differences in the channel audio levels.

Tim


For us newbies, can you explain the 19:1 vs 4:1?

[Tilt]

It's really just matching the incoming audio level to a level appropriate for the amplifier is all.  These amplifier boards are used in different types of machines.  Take for instance a 3902 MPU board used in game kings/Igames.  It can be used in older cabinets that have a single speaker and no external amplifier.  The MPU board amp drives the speaker.  Now take that MPU board out and put it in a newer 17" cabinet that has an external amplifier and stereo speakers.  The audio level that can directly drive a speaker is too high to amplify again without causing distortion and clipping.  So that's why they have the ability to reduce the signal first, before it reaches the amplifier.  IGT engineers must have determined that having the option of reducing the signal at 19 to 1 and 4 to 1 ratios would be appropriate for the machines they intended to use them in.