IGT S2000 Triple Double Diamond 2003 Slant Top - No Sound

[WaylandS]

Hello all,
First time poster here.  I can't find any previous topic related to my specific machine or issue so here goes.  I purchased and Triple Double Diamond 3 reel mechanical slant top at a garage sale about a month ago.  The machine was DOA, but I only paid $130 for it.  After reading posts on here and with a little help from a friend of a friend we determined that the MPU board had the dreaded Varta battery damage.  It was a 502A board.  I bought a 504B board and inserted all of the eproms from the original board.  This bought the machine back to life and everything but the coin comparitor was working.  Fixed that issue by replacing the coin comparitor.  So everything was working and I was playing the machine a lot.  The sound from the machine only played from the top left speaker but I read that was normal from various posts to this site.  About a week later I noticed some static noise coming from the left speaker.  It occurred when idle and during game play.  The static got more frequent and progressively worse until there was no sound at all coming from the machine.  Everything else is working fine and there are no errors.  I have swapped wiring from the left to the right speaker but still no sound.  Checked speaker connections from the back plane board to the inline amp and to the speakers.  Checked 12V power going to the amp board and it is good.  I ordered a tested inline amp board and replaced the original and I still have no sound.  Checked the volume level is set to 8 in the software.  So this is basically where I'm stuck with troubleshooting and looking for some expertise with this problem.  My 504B MPU board does not have any sound SIMM on it and neither did the original 502A board.  I have attached pictures of the machine and the eprom chipset on the MPU board.  The Varta battery has been removed from the new board, but the coin battery is present.  Any help is appreciated.  Thanks, Wayland

[WaylandS]

In further troubleshooting this issue, I was able to attached a pair of powered computer speakers to the speaker wiring harness coming off of the back plane and going into the in-line amplifier.  With the volume turned all the way up to level 10 and the computer speakers turned all the way up I can hear the normal sounds being generated during during game play although it is very low volume.  Some component on the MPU board driving the sound to the amplifier must have gotten really weak and was probably causing the static noise I was hearing before.  Is there a schematic available for the 504 board?  I'm thinking I can just replace the bad component(s) on my 504 board that are responsible for driving the sound signal to the amplifier and I can use the ones from my 502 board that had the battery corrosion.  Is there a schematic available for the 500 series boards?

[Amechanic]

I doubt it's the MPU board, but possibly your sound amp board.. That's a small circuit board about 3-4" square. I would think it's mounted in behind the top glass of your slant top.. They are mounted it the top box of the up right cabinets..

[WaylandS]

I tried a new amplifier board that is known good. Same results. Has to be something on the MPU board. Even the amplified sound from the computer speakers is weak.

[Amechanic]

I wonder if your computer speakers had larger sound coils and were not able to be powered by the slot machine. Too bad you don’t have an extra speaker from another slot machine to try.. I’ve heard of this happening on the S+ MPU, but not on these from the S2000 machines.

[RB]

Check U66. YM2413B is a sound chip. I've had to replace one before. It's a 18 pin thru hole dip.

[WaylandS]

Just a follow-up on this issue.  This weak sound problem was NOT caused by the in-line amplifier.  I was able to obtain another 504 MPU board, installed it and the problem was resolved.  I am assuming the op-amp U85 on the old MPU board is bad but I don't have a schematic to see if that is what is driving the audio signal to the in-line amp.  U85 is in the vicinity of all the sound related components on the MPU board so I'm guessing here.
[/size]
[/size]Like I said in my post, sound was being generated but not very loud and I ruled out the in-line amp as being the issue with a known good one.  The good news is that the new 504 board has the MML sound board and a 042 SIMM as well so now I have stereo sound.  Much better. 
[/size]
[/size]If anyone has a schematic for a 504 MPU board I'm willing to fix my old one for a back up.  Just not willing to waste a bunch of time swapping components willy-nilly.
[/size]
[/size]Thanks,
[/size]Wayland