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FT Sound Problem

  • Thread starter Thread starter xenon325i
  • Start date Start date
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xenon325i

I have a strange problem with sound on my FT in that occasionally it hangs (no sound until ball-drain) or it plays the wrong sounds for the event that just happened. It seems to happen more when the game is under load e.g. during multiball (but that my just be coincidental with more sounds being played anyway so more noticeable) but even on a gentle game it sometimes plays completely the wrong sound.

I assumed there was an issue on the A-12738 sound board as the CPU drives the dot-matrix display down exactly the same ribbon cable and the DMD is perfect. So I put in a new sound board but that made no difference :(

In fact, the whole game is perfect other than this issue - all tests go through 100% including sound except for when this problem occurs. E.g. if the problem occurs in gameplay and I immediately go into test mode for sound, there's a good chance the sounds will be wrong until reset.

I measured +5v ripple at about 150mv which seemed a bit high, so I renewed C5 on the power board and that's now about 60mv but the problem persists.

Any suggestions gratefully received.
 
Try reseating all the connectors on the ribbon cable between MPU, fliptronics and sound board...
 
Hi Moonraker - I've done that - those boards have been in and out of the backbox more times than I don't know what of late.
 
have you another machine that you can borrow a set of ribbon cables from? if that doesn't work then try swapping the CPU to help verify that is the problem area...
 
First check the long (4 way see below) ribbon cable throughly for any visual knicks

Then, as you have no replacement ribbons try this - Get the sound issue to occur in a game (do this with glass off) once it happens, open the backbox leave the light board latched initially but glass out. Once you unlatch check if any change if none, wiggle the longest ribbon cable between the sound and DMD board - it goes DMD board > Sound > Fliptronics > CPU.

If the problem goes or changes at any point it is ribbon cable related however you do normally have DMD issues as well at the same time.
 
Have a similar issue and its something on the board. Nasty fault, haven't tracked it down yet.
 
Thanks all. As I mentioned, I've put in a new sound-board but the problem persists. The ribbon cable I have in there looks OK (no kinks or separation of IDC connectors) but I'm going to make up a brand-new cable anyway, just to rule that out.
 
New ribbon cable made no difference. Some calls never seem to happen - for example, I've never heard it call out "Rock the Boat!..."
 
xenon325i said:
New ribbon cable made no difference. Some calls never seem to happen - for example, I've never heard it call out "Rock the Boat!..."
Click to expand...

Further developments. The only board I hadn't isolated was the Fliptronics board. Just for the sake of completeness I disconnected the data from the board and the game works perfectly if I fling the ball around with my hand. I get all the correct sound calls including some I've never heard this particular FT make.

I reconnected the Fliptronics board and tried again - all perfect. I assumed relocating cables had fixed so settled down for a game but the problem returned. I then discovered that the game was fine until I started using flippers.

Next I disconnected the flipper power and ran the game. Again, all was perfect even if I banged the flipper buttons in video mode or to change lanes so it seemed the digital side was ok.

My assumption now was that it could be nothing other than the diodes on the flipper coils which prevent back-emf from hitting the drivers. Surely this must be?!

Changed the diodes on flipper power and holding coils but it has not fixed the problem.

What next?
 
xenon325i said:
Further developments. The only board I hadn't isolated was the Fliptronics board. Just for the sake of completeness I disconnected the data from the board and the game works perfectly if I fling the ball around with my hand. I get all the correct sound calls including some I've never heard this particular FT make.

I reconnected the Fliptronics board and tried again - all perfect. I assumed relocating cables had fixed so settled down for a game but the problem returned. I then discovered that the game was fine until I started using flippers.

Next I disconnected the flipper power and ran the game. Again, all was perfect even if I banged the flipper buttons in video mode or to change lanes so it seemed the digital side was ok.

My assumption now was that it could be nothing other than the diodes on the flipper coils which prevent back-emf from hitting the drivers. Surely this must be?!

Changed the diodes on flipper power and holding coils but it has not fixed the problem.

What next?
Click to expand...

The obvious thing would be to try a different fliptronics board, it's a guess but there's possibly something feeding back from the board to the signal at the ribbon cable connector?
 
Yes, something on the board is corrupting the data bus is my guess, but I don't have an exchange unfortunately.
 
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