(Topic ID: 201338)

installing fans in the head of old SS pinball Machines

By jmorrow7

6 years ago


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  • 19 posts
  • 9 Pinsiders participating
  • Latest reply 6 years ago by Travish
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#1 6 years ago

I have a Gottlieb System 80a 1982 Devil's Dare. I am having an issue with the speech/soundboard. When you boot the game up after it has been off for a while, everything works fine. Then at about 15 minutes later (every time like clockwork) the speach starts to play with inconsistant pitch. It slows down to a low incomprehendable growl sound. After a lot of trial and error to solve this issue, I decided to leave the head open and clip a small desk fan to the case blowing towards the soundboard. That fixed the problem. I played for an hour that way with no issues. However when I turned off the fan (leaving the case open) the voice chip issue started up five minutes later. Just to be sure, I turned the fan back on and the problem stopped within a minute or so.

I want to put a computer case fan in the head blowing out the vents. I need recomendations on fans that would work well and also how to tie them into the power of the game. I am looking for simple as possible answers please.

#2 6 years ago

Why destroy the head? Make a backbox cover out of plywood, get a 12v D.C. adapter 1 or 2 amp. Since heat rises, I would install two pc fans on the bottom of the backbox cover blowing in and have air hole vents drilled into the top of the cover.
If you really want to get crazy, add two more fans on the top blowing out.
Although, remember that no matter what you do, you will be sucking in dirt and dust into the backbox. Have you ever looked inside a computer case?

#3 6 years ago

I'm not an expert on gottlieb SS games. But installing a fan doesn't seem like a proper (or long-lasting) solution to this problem. Something inside the game is failing and putting a fan in there isn't going to turn back the clock on whatever is causing the problem.

Figure out WHY the game is failing and fix that.

#4 6 years ago
Quoted from Mikala:

Although, remember that no matter what you do, you will be sucking in dirt and dust into the backbox. Have you ever looked inside a computer case?

Yes, I can't tell you how many times I have cleaned dust out of my PCs over the years. I used to clean them out every year or so.

#5 6 years ago
Quoted from CrazyLevi:

ISomething inside the game is failing and putting a fan in there isn't going to turn back the clock on whatever is causing the problem.
Figure out WHY the game is failing and fix that.

For whatever reason, the sound board is getting over heated. If a fan keeps it cool, and thus it doesn't malfunction, isn't that finding the problem and fixing it? I am new to pinball repair. Am I missing something?

#6 6 years ago

He means all the other devil dares don't need fans so something is wrong. So instead of fixing with a fan just fix the issue.
When I got my Gorgar it had a hole cut in the head and a computer fan installed to hold down the heat. I put warm leds in the back box and changed the board to get rid of those super hot resistors and now have a whole in the head.

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#7 6 years ago
Quoted from jmorrow7:

For whatever reason, the sound board is getting over heated. If a fan keeps it cool, and thus it doesn't malfunction, isn't that finding the problem and fixing it? I am new to pinball repair. Am I missing something?

You need to fix the problem, not blow cool air on it. Even if this “fixes” it for now, it won’t fix it for good. And sucking all that dirt Into the head isn’t gonna help the game either. That’s all I got. I’d suggest making a tech thread about your particular issue and maybe someone who knows these games can help.

#8 6 years ago

fan is just going to suck dust inside like my PC box does.

See if you can find the overly hot device. Finger right after power down test should be pretty safe. Nothing over 12 - 25v potential on that board. just stay grounded against the side rail when touching around on the circuit board. I have had some 6802 chips that get smoking hot after 15min, start having issues, and then ultimately fail entirely.

#9 6 years ago

A common technique for isolating a heat up problem is to use Freeze Spray (or I guess a duster air can turned upside down).

Let the board heat up to where it has failed. For small boards, you can do it one IC at a time. Freeze a chip, see if it fixes it. Sometimes, you may have to cycle power to get a cooled chip to work again until it heats up again.

For large boards, freeze half the board and see if you have fixed the issue. If not, freeze the other half and check again. When you have found which half contains the problem chip, divide that section in half and try again. Keep dividing until you get it down to only 1 IC or component/area.

Sometimes, its not an IC but rather just a bad connection that is effected by heat.

To speed up the process, we used to use Blow Driers to heat up the ICs instead of waiting 20 minutes for each failure.

#10 6 years ago
Quoted from jmorrow7:

For whatever reason, the sound board is getting over heated. If a fan keeps it cool, and thus it doesn't malfunction, isn't that finding the problem and fixing it? Am I missing something?

Your method is treating the symptom instead of the disease. Better solution is find out why the component is heating up and failing.

#12 6 years ago
Quoted from YeOldPinPlayer:

Your method is treating the symptom instead of the disease. Better solution is find out why the component is heating up and failing.

Certainly. It's like increasing the value of the fuses to prevent them from burning.
And connecting a fan on the 12 volts will pull a little more on the power supply ... which will also heat a little more .

On these evolved sound boards, it is imperative to change all the chemical capacitors by new ones - the original ones are over thirty years old and are cooked!
Try then to identify the IC that are hot - Replacing the EPROM and the CPU by a CMOS version can be also a good alternative.

If the speed of the voice is drifting, it means that the clock of the SC-01 is unstable. This one being generated by the 1408 (U19) and the LM741 (U21), one must look at this level. But it is imperative that the + 12v and -12v power supply are stable, otherwise the oscillator will drift. If the capacitors have not been replaced, it's not surprising.

#13 6 years ago

Thanks all for the helpful advice. I am going to take it and see if I can isolate whatever is overheating on the board and forget the fan idea.

#14 6 years ago

Is the game converted to LEDs? That is one quick and sure way to cool. If so you might just mount a small 12v fan in the head pointed at the board.

#15 6 years ago
Quoted from John_I:

Is the game converted to LEDs? That is one quick and sure way to cool. If so you might just mount a small 12v fan in the head pointed at the board.

Yes, it is all LED lit. Are you saying that the LEDs could be making boards run hotter?

#16 6 years ago
Quoted from jmorrow7:

Yes, it is all LED lit. Are you saying that the LEDs could be making boards run hotter?

No LEDs make the whole game run cooler, so that is a good thing.

#17 6 years ago

Okay,

I think I have found the issue. The soundboard has one module that feels considerably warmer than anything else on the board. And fortunately, TNT Amusements in PA (who sold me the pin) said the board is still under their warenty for the game. So, I am going to remove the sound board and send to them to repair it. I am guessing I will have it back and installed before December. I will update then.

Thank you guys for the help!

#18 6 years ago

You made a good choice with TNT. Watch some of their videos on YouTube. Great guys.

#19 6 years ago
Quoted from jmorrow7:

TNT Amusements in PA (who sold me the pin)

You should have said that first. You'll be fine.

Just don't let them take it on the roof for service.

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