Bally 2240 sound board issue

[kjnuke]

New to the site. I finally started working on my Bally 2240 E series. Luckily after cleaning, lubing and oiling the reel assembly, a few starters and flousecent bulbs everything is working except the sound. Found out whoever had it before me had disconnected the primary and secondary to the sound transformer. Plugged them back in and pressed the test button on the sound board, board goes through a series of different sounds and then locks in on a certain warbling sound and won't shut off. I rebooted the machine and the sound goes away, playing the slot and no sound.
Pressing the test button on the sound board starts the whole process over again with it locked in on that warbling sound. I have checked the ribbon cable for bent or broken pins and swapped around the connector from other posts I've read, but that didn't help.
This is my 1st slot, so definitely a newbie, but I do have some early solid state pins I've messed with.
Hopefully something easy that I just don't know about.
Thanks

[slcjeeper]

Start by removing the sound board and remove all socketed chips, clean the legs and inspect  / clean the sockets.  Reassemble and let us know what you get.

[kjnuke]

Thanks for the reply.
I pulled the board and removed each socketed chip and cleaned both sockets and legs on all.
Everything looks OK, no bent legs and sockets appeared OK and the legs fit tight. No hacks on the board. Replaced 3 of the 4 capacitors (waiting on the last from Mouser) installed and same issue. Board seems to work OK except for locking in on the 4th different sound during the test. Wondering if possible daughter board issue. I don't want to replace the sound board if it's something else, but maybe it's got a bad chip or something. I don't have the schematics.
Voltage reading on the test points might be the issue. Per the Bally E series manual test points 2 and 3 should read approximately 2.5 VDC. Not sure what to reference that to in regards to ground. Chassis ground to test points 2 and 3 read 0. Test point 1 to test point 2 reads 1.8 VDC test point 1 to test point 3 reads 2.3 VDC. Maybe I'm not measuring right point to point. Didn't see a ground on the board.

[kjnuke]

I fixed the problem. Ended up being the power connection to the daughter board on the I/0 was dirty. Wiggled the connector with power on and the problem went away. Cleaned and now sound works as it should.

[slcjeeper]

Good find! I was going to suggest looking at that small board on the I/O sound socket. They work their way loose during play, so if you lose sound again, check there first.

[kjnuke]

Thanks for the help and suggestions slcjeeper!
I'll keep an eye on it and know that's probably the problem if it happens again.

[kjnuke]

Follow up to the issue. It came back. I again removed the daughter board sound module off of the I/0, used some magnifying glasses I have and found one of the leads of the connector that plugs into the I/0 had no solder on it. Looks like that's how it was when new. I'm assuming this was an intermittent issue with this slot forever, but not sure. After soldering that one pin the problem is again fixed.