Sound Issues... round 2

[SilverFerret]

Some of you may recall that I've had some weird sound issues on my Game Maker where some of the sounds are present and some have disappeared. For instance, when I make a bet, I hear a ding (as I should) but when the cards where dealt (in video poker) I wouldn't hear the dealing cards sound. In keno as the numbers are drawn I would hear nothing but when a chosen number was hit, I would hear the ding that I was supposed to....
On to round 2...
Same issue but now some of the sounds that were missing last time are back and other sounds that were there are now missing. For instance I hear the card dealing sound but no longer hear the sound when a chosen keno number is hit.
It was working fine for a few month and I'm not sure what I did to fixed it last time. I did clean whatever contacts I could and tried to move the EPROMs a bit to hopefully scrape off any build up that may be making a contact issue.
I'll try the same thing but does anyone have an idea about this that I haven't tried?
Thanks, Jim

[dextrose42]

Does the rom check pass in the diagnostic menu?  That might track down which chip isn't talking correctly.  Could be bad /dirty chip sockets or chip legs.  If the legs are black they would need cleaned.     

[SilverFerret]

Everything seems to pass the test but the sounds. I did the Eprom test and the mains and games all passed. Only when I go to the sound test and touch each of the sounds, only some make sound. The ones that don't are:
Button
Service
Tilt
Reel Spin
Number Match
Number Pick and
Tone
I lifted and replaced all the game Eproms and the mains but no change.
Thanks, Jim

[dextrose42]

Did it take a lot of force to get the chips out of the socket?  If you can pull the chips out with just your fingers, the sockets are "bad".  I've  also seen legs getting folded over or missing the socket entirely when people reseat them.

[SilverFerret]

IMO all the sockets seem fine and hold the EProms snug as they should be and all the legs are fine. It's odd because the sound issues span multiple games, not just any one in particular.
Thanks, Jim

[SilverFerret]

Okay, apparently it must have something to do with the mains. I had cleared the machine, lifted and pressed down the game chips and the mains with no results. I even changed a couple of games that I thought might be suspect and nothing. It wasn't until I lifted the mains all the way out and sprayed contact cleaner in the sockets that the issue was corrected. This is the second time I've had this issue and I don't understand why all of a sudden after owning the machine for about four years without issue.
Hope it helps someone.
Thanks, Jim

[SilverFerret]

After much trial and error, I may have  zeroed it in a little closer but not sure. Anyone know what this chip does? Seems every time I turn on the machine, I have to pull this chip and spray contact cleaner in the socket to get the sounds back. I'm stumped but it seems the mains aren't the issue at this point.
Thanks, Jim

[dextrose42]

Thats your sound generator.  The tones / music it makes is code stored in the mains.  You are looking at either a bad chip or bad socket -- I'm leaning toward bad socket, especially if it works part of the time.

More info at:
http://cube.gfxile.net/t/index.php?page=journal&journal=YM2149F
http://en.wikipedia.org/wiki/General_Instrument_AY-3-8910

[SilverFerret]

Okay, if that's narrowed down, the next question is... how does a socket go bad? I had never touched the chip until having the sound issues. Would it be worth replacing the chip first to see if the chip is the issue or are they expensive and hard to find. If the socket is bad, does it mean replacing the whole board?
Thanks, Jim

[dextrose42]

Depending on the type of socket the socket pins lose tension, the solder is cracking on the board that holds the socket in place, or there is contamination in the socket pins -- the metal oxidizes and then gets bad connection and the contact cleaner may only be partially removing the oxidation. 

Check for cracked solder, replace just the socket, try putting mounting the chip in a new machine pin socket and putting that into the current socket to see if it grips any better.

There is a chance that the pins on the chip are damaged and that would go back to either replace the chip or put it into a machine pin socket and solder it together to act as a carrier....

I quick search for that part number makes it look like it may not be trivial to track down a replacement.  There are some random arcade parts houses that may have them, but I think the last time I had to replace one I ended up having to find a different video game board to steal one off of....

[Badbaud]

A AY38910 will also work.

[SilverFerret]

I looked at the board and don't see any issue with the socket but it's probably something the eye can't see. I'm more willing to try to replace a chip before trying to replace a socket or lastly the board. I'll post in the classifieds for those chips and see what responses I get.
Thanks dextrose42 and Badbaud,
Jim

[Badbaud]

Usually removing the chip from the socket and cleaning it's legs with a pink eraser will also clean the socket when the chip is reinserted and let the chip work.

In most cases you don't have to remove the IC completely.

Raising up a IC partially out of a socket, first on one end, then back in, then on the other end, then back in, has got a board to work for me many times.

There is a term called "dissimilar metal contact" when you have tin legs plugged into a socket the metal contacting area tends to oxidize and eventually cause a electrically bad connection.

Moving the IC up and down in the socket usually fixes the problem.

I hate the tooled sockets that Bally used, just trying to get the IC pins back into the socket holes is a PITA.

[SilverFerret]

Believe me, I've done all that. I have a new chip on the way to try that first and I'll keep trying to get this one to work until the new one arrives.
Thanks, Jim

[SilverFerret]

Not quite sure if I'm ready to write this off as topic solved (I will anyway) but I received a new sound chip today and replaced the existing one and everything seems to be working properly.
Thanks, Jim