Mystic sound issues

I'm having issues with the sound on my Bally Mystic and looking for some help. So the sound quit working completely so I replaced all the caps on the sound board and thought I fixed it as it played fine after that and all the sound worked, this was just a few days ago. Fast forward to today and before I could finish a game the sound stopped working again. I turned it off and back on and the sound worked again, but after 2 balls the sound started to play one solid noise and thats it and wouldn't stop, turned it off again and now it has no sound at all. I havent replaced the pot but do have a new one so I was going to swap that out to see if it helps, but other than that I'm at a loss, any ideas of what could cause this and what I should look for? Thanks for all your help as always

#2 3 years ago

TPR

frunch

Pinside member

Have you reflowed the solder on the header pins of the sound board and mpu? Replaced the connectors between them?

#3 3 years ago

ODENONMYSIDE513

Pinside member

Mpu is an alltek, not sure of the age, was in there when I got it. It appears some connectors have been replaced, not for sure about all of them. Sound board header and connector do not look like they've ever been replaced, haven't reflowed either. So here's an update, re seated all the connectors on the mpu and sound board and checked the voltage at the sound board and the regulator board, see below for readings. After I did this the sound worked for 2 games. Midway thru the 3rd game it went to a solid tone, shut it off and now no more sound. Shut it down for a few minutes, turn it back on,has sound for a few seconds into game and then it stops.

Sound board

TP1 - 13.7
TP2 - 5.09
TP 3 - .051
TP 4 - 2.87
TP 5 - 2.49
TP 6 - .051

So after I typed out all of the above I turned it off and on and was able to play a full game with the sound working, I'm sure it won't last though. Thanks for the help French, still consider myself a noob at alot of this but have learned alot just reading posts on here and have even surprised myself at how far I've come with all of your guys help.

#4 3 years ago

TPR

frunch

Pinside member

No prob!

Voltages look good, as far as i can see. I'd try reflowing J1 pin the sound board and re-pin the connector that plugs into it.

#5 3 years ago

ODENONMYSIDE513

Pinside member

I'll give that a shot, thanks again

#6 3 years ago

ODENONMYSIDE513

Pinside member

So I replaced the header pins but I have a question about the connector. My first experience with re pinning connectors was recently on my Lost World rectifier, someone had directly soldered the pins to the header so I re did all that successfully. When I went to re do the connector on the sound board it looks different. So not to sound dumb but can I replace this with a regular connector and if so, how do I go about this?

20201122_132754 (resized).jpg

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#7 3 years ago

TPR

frunch

Pinside member

Hey, sorry it took a while to get back. As far as replacing the connectors, it's a little difficult getting 2 wires into one slot. What i usually do is strip extra insulation off both wires, twist both stripped ends of the wire together, then crimp down both of the sets of the connector pin tabs on the twisted-together stripped wiring. It may be a bit difficult getting the 2 wires into the housing as well, so it sometimes is necessary to strip the wiring back a bit more. You can always add a little heat shrink tubing to clean up the exposed wiring too. It's not perfect or ideal, but the only other option would be to replace the connector with another IDC style connector.

I've had success doing connectors that way on plenty of games, it just takes a bit of practice and patience.

Edit: there's a thread covering this very issue happening right now: https://pinside.com/pinball/forum/topic/best-way-to-double-up-a-connector#post-5979915

#8 3 years ago

ODENONMYSIDE513

Pinside member

Thanks @frunch, I havent had a chance to mess with this the last few days but here's where we are. Turn it on and the sound will work for 2-3 balls and then stops working. Turn it off and on and the sound may work for 1 ball and quit, but if I turn it on say 5-6 times repeatedly the sound will work just fine. I left it on tonight after doing this and played 5-6 games over a 2 hour time frame and the sound worked the whole time. I did see the thread you linked, very helpful. Thanks again for your help

#9 3 years ago

TPR

frunch

Pinside member

No prob! Hopefully you'll find it is indeed a connector problem, but it's possible the problem could lie elsewhere. I just know from experience a lot of games from this generation have connector problems sooner or later, so that's usually the first place I'll start.

Good luck!

1 year later

#10 2 years ago

BDV

b_rent

Inactive member

Saskatoon, SK

2y 8,000 1 1

Hi ODENONMYSIDE513 do you have any update on this?

I've had a Bally Mystic for several years, and maybe since I purchased it the sound behaves a bit like you describe. In my case sound usually works when machine is turned on and will work for a few balls or a few games, and then sometimes the sound turns fully off, or sometimes it sticks on a tone (with no other sounds, etc. just the tone). If I power-cycle the machine, it will almost always work properly again, and again for a few balls or a few games.

I haven't done anything yet, but after reading on here I'm thinking re-seating the connectors is low-hanging fruit. But wanted to hear how your problem/solution has evolved?

On the plus side, it makes it easier to just turn the machine off after the game that had the sound go bad finishes and go to bed. If it worked perfect I just might play all night!

#11 2 years ago

ODENONMYSIDE513

Pinside member