Title Fight
Gottlieb, 1990I have a Title Fight that boots and plays, but the sound board doesn't generate sound when first powered up.
If I open the backbox and press the reset button on the sound board, it boots up and starts working normally.
Any ideas? I'm not sure if this is the MPU board failing to initialize the board, or something with the sound board itself.
Quoted from ForceFlow:My first guess would be bad caps that aren't charging up within the time allotted upon a cold boot.
Would this still be an issue when the game has been running a while? Power off-and-on is all it takes to kill the sound board again. It feels like a logic problem; some reset line not getting pulled low or high on startup.
Let's say you're right, though: Which caps would you look at first?
I investigated this a bit more, and the LED on the sound board is locked on when the game first powers on. So it's not running. Hitting the reset button gets it going.
Powering the game off, then on again USUALLY locks up the sound board again. But every now and then it continues to work after the power cycle.
Maybe something with the board's reset circuit, then? What does the reset button bypass on the schematics?
Quoted from ForceFlow:Maybe something with the board's reset circuit, then? What does the reset button bypass on the schematics?
Gosh, I wish I had schematics. 
Something has changed; it only started doing this recently. So it could easily be deteriorating capacitors or oxidizing connectors causing this side-effect.
I'm guessing the reset button simply grounds the reset line on the sound board's CPU. I haven't traced it out, but that's usually how they work. The MPU board is probably supposed to somehow pull the same reset line low on startup, but isn't for some reason.
Assuming all that's true, I guess that leaves one of these:
- Floating ground between the two boards (aren't Gottliebs famous for this?)
- Issues with the connectors between boards
- Voltages too high or low for the reset assert to work (possibly bad caps)
- Logic failure on the MPU board
I don't have schematics so it's hard to get into specifics. I can probably eliminate the first 3 possibilities without schematics. Anyone know where I can find some?
One easy thing to check for would be cracked solder joints, especially the header pins.
Also rub the header pins a little bit with a pink rubber eraser.
Schematics are in the parts catalog if they aren't in the manual.
Brush every connectors and resold every components then try to launch it.
Screenshot_20190703-183813_Drive (resized).jpgScreenshot_20190703-183834_Drive (resized).jpgScreenshot_20190703-183850_Drive (resized).jpgScreenshot_20190703-183901_Drive (resized).jpgScreenshot_20190703-184016_Drive (resized).jpgScreenshot_20190703-184106_Drive (resized).jpgScreenshot_20190703-184116_Drive (resized).jpgBefore you go ripping stuff apart....try going into diagnostics and do a factory restore. Don't assume because the battery is dead or has been popped out that the system is indeed restored. You need to actually go into diagnostics and hit restore. I've had some real strange stuff magically go away on some Gottliebs with a system restore. I sort of start with this step first on a Gottlieb as I have chased my tail before on strange behavior and this worked. Good luck!
Quoted from Gotpins:Before you go ripping stuff apart....try going into diagnostics and do a factory restore.
That was a really great idea, but...no luck.
Well, time to roll up the sleeves. Id start looking for cold solder joints at the header pins of the sound board and CPU like forceflow said. Just reflow them to be sure, it only takes a few minutes. After that....do you have another System 3 game around with a working sound board? Try swapping and see if your problem is on the soundboard or stays with the game.
Quoted from slghokie:pinwiki has a great Gottlieb sys3 with a whole section on sound. Look for section "5.13 Sound Problems"
http://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_3#Sound_Problems
Good idea. I always forget Pinwiki exists...
Thanks guys. You've been a big help.
I can trace the reset line (MR) from the MPU board all the way to pin 1 on the G5 AND gate IC on the sound board. The same reset line drives the other boards too, so since everything else boots it's a safe bet that the sound board is also receiving the reset signal.
We've eliminated the connectors and harnesses as potential problems, and the reset line has to be working on the MPU board. So it's most-likely the IC at G5 on the sound board. I've ordered a replacement and we'll see if that resolves it.
Update:
Not a satisfying conclusion, but I swapped the IC on the sound board with no effect. I have another System 3 game, so I swapped the sound boards and ROMs and everything worked in both.
My guess is the voltages have drifted outside the tolerance of the original board, but the other one has wider tolerances.
This particular cap is a ceramic, 0.1uF -- Tied from pin 3 of G5 (Reset*) to ground (G5 pin 7). It is used to stretch the length of the reset signal.
These don't leak and seldom fail. But if it does go open internally, it can result in a shorter reset signal.
Can't measure with regular meter but can check with cap meter - disconnect to check. But since these caps are so cheap, if you're going to disconnect it then you may as well replace. Also, G5 is a CMOS type integrated circuit which means it can easily fail due to ESD if mishandled.
If you replaced the CPU - what did you use? There is only one brand that is still made (WDC), the rest are old stock from many years ago. A ton of the "Rockwell" marked parts are from China as reclaimed counterfeits.
We have a Swemmer MPU and it appears to be working wonderfully. Do you think I should go ahead and replace that cap? Thanks
G-P-E
The cap is possible but unlikely.
There is no power-up reset on this board - it relies on the reset being sourced by the CPU board.
Since manual reset works - this says G5 works (or maybe just input 1 bad but unlikely).
Follow the reset line from the sound board back to CPU board. Probably a bad connection between the two.
Quoted from G-P-E:The cap is possible but unlikely.
Hmm, gotcha. What could possible be bad on the sound board to prevent the reset? Is it G5? I know r34 is okay
Quoted from G-P-E:The cap is possible but unlikely.
There is no power-up reset on this board - it relies on the reset being sourced by the CPU board.
Since manual reset works - this says G5 works (or maybe just input 1 bad but unlikely).
Follow the reset line from the sound board back to CPU board. Probably a bad connection between the two.
Great! So maybe bad wiring?
Quoted from G-P-E:Added to post #23. But just to be clear -- it doesn't work until you reset it manually and then it works?
Correct!
Quoted from G-P-E:Then, my first guess would be a bad connection between the two boards.
Perfect, thanks so much. I just replaced the J2 connector so I’ll start from there. I’ll let you know!
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