Gottlieb Volcano Repair Help

(Topic ID: 197887)

Gottlieb Volcano Repair Help

By AGray8900

10 months ago

Topic Stats

  • 17 posts
  • 2 Pinsiders participating
  • Latest reply 9 months ago by AGray8900
  • Topic is favorited by 1 Pinsider


Linked Games

#1 10 months ago

I have created a post before and got a few responses but I was unable to really get anywhere and I am so close to getting this game in 100% working order it is driving me crazy! Is there anyone out there that would be willing to talk through my last few issues with me on the phone? I am having issues with my displays and with 2 coils and completely burnt out on ideas on what to try next and a phone call would greatly speed up the process.

Current issues:

No displays. All blank. I have tested all voltages (ac and dc) and they are all good. I have also tried disconnecting all the displays but 1 at a time (with the game off every time) Every connector has been re-pinned and all pads cleaned up nicely and everything checked for continuity - Not entirely sure where to go from here

My other issue is with 2 coils. 1 doesn't fire at all and the other stays on. I have replaced the transistors and coils to both of these and am still having the same issues.

Please and thank you for any help!

#2 10 months ago

Let's get you started.
Did the displays =ever= work?
If you have 60V DC and the 8V "bias" voltage, then the large displays should work.
The BIP/credit display works from the 42V and 3V bias voltage.

If you have voltage, and have =never= seen the displays work, try "recharging" one with this procedure:

Don't over-do-it. We are only looking for signs of life to rule in/out tired displays.

After you recharge it, disconnect the other 4 displays, connect the recharged display, then power on.
Got display now?
Chris Hibler - CARGPB #31 - The Place to go for Pinball Repair Info

#3 10 months ago

Thanks for the response Chris!
I did have the displays lighting up but they were only showing garbage. Now I get nothing but I was able to trace back through my cpu board (applied ground to the input of z24 7404 and saw nice bright displays) and so I went back further and found that I don't have 5v going into my u5 display control chip. What I have done now is pulled my control board out and begun testing continuity on everything.

I have found that I have a few things that stand out. C34, C11 & C30 seem to have shorts through them so I am getting parts for those tomorrow. Does this sound like I may be on the right track?

#4 10 months ago

Well, I replaced those components and still get the same readings from them so I guess they were never faulty... Didn't change anything on my game, still no displays. Like I said, I can apply ground to the 7404 chips and get an output at the displays so I know they work. It seems my voltage at my display control chop (u5, 6532-2) isn't high enough (1.5v). This should be 5v, correct?

What I am thinking at this point is that that chip just isn't getting enough power, but I don't know why. I have 5v at the board so now I'm working my way through the circuit towards the chip to see where the issue is. Any input is appreciated as always!

#5 10 months ago

It's not uncommon for the 6532 ICs to fail.
The most common is U4, which drives the switch matrix. It fails via HV being shorted to the switch matrix.
But, I've seen U5 fail too. Most of the time when a 6532 fails, the MPU will no longer boot, but I've seen them fail in ways that still allow the MPU to boot.

At this point, I'd socket and replace U5, which is non trivial. If you have significant PCB rehab experience, have at it. Otherwise, send it to a pro. If you are in the US, I can take care of it for you.

6532 chips can be purchased here: although you'll have to contact him (Todd) directly as his web site for that part is still under construction. Good seller.

Chris Hibler - CARGPB #31 - The Place to go for Pinball Repair Info

#6 10 months ago

Thanks Chris. I will get one ordered and replaced. Shouldnt be a problem for me to do myself. I have ordered from Todd before so I will shoot him an email!

#7 10 months ago

Since I will probably need more for the order to reach minimum on shipping would you be willing to help talk me through my issues with my 2 coils? The coils are the fire pit and the hole kicker. The fire pit locks on, the hole kicker doesn't fire. I have replaced the coils themselves and also the transistors but have the same issues. These I have put less work into tracking down issues than the displays so I am open to every idea to check. I am home all day so I can check things as soon as you mention them!

#8 10 months ago

Check the schematics but I believe that both of those coils may be driven by under play field transistors. Todd also stocks 2N5884 transistors which are a good substitute for the OEM part. Get a few of those. 1N4004 diodes may come in handy too.
Chris Hibler - CARGPB #31 - The new place for pinball repair info

#9 10 months ago

The transistors under are new. I replaced those and the coils. The fire pit is just stuck to ground, and the other one if I apply ground it doesn't fire.

#10 10 months ago

I just ordered some of the u45 transistors for the driver board. I don't know how to check those but figured for a couple bucks ill just replace them and see. Sound like the correct next step or is there something else?

#11 9 months ago

Thanks for your help through this Chris, unfortunately not making progress on displays... I replaced the u5 and even replaced the u4 with no luck. Still no displays! Any other ideas for me? I am pretty sure I have tested all the resistors and caps over the entire board. Connectors connections all test good. Any other ideas for me?

#12 9 months ago

Let me make sure I understand completely.
The game boots, goes into attract mode, can even enter diagnostics, but you have no displays. Is that correct?


#13 9 months ago


#14 9 months ago

I can play the game and everything works perfect besides the displays and two coils.

And I know the displays work as I can apply ground to pins on the 7404s to get an output on the displays. (except the credit display, not sure if that works)

#15 9 months ago

A logic probe is what you need now. Start at the 7448 outputs and work backwards.
Chris Hibler - CARGPB #31 - The new place for pinball repair info

1 week later
#16 9 months ago

Good news update! The last two coils are fixed and working! Play field is finished! Now back to the displays. My goal is to have them finished this week as I am having a big get together Saturday. I am going to do what you said and start at the 7448s and work backwards. I will let you know what I find.

#17 9 months ago

OK so I have done an extensive amount of testing and this is what I have going on. The u5 outputs going to the digit strobes reads 2.5v. Is that normal?
I also found that if I ground inputs of the 7404 on the digit strobes section parts of the displays light up.
If I ground inputs in the segments section I don't get any output on the displays.
The 7404 before the 7448s was replaced and didn't make any difference.
I am wondering if it could be something BEFORE u5. I wonder this because none of the displays are lighting up and I don't know what I should be getting for readings along the address/Data busses or their outputs out of u5 going into the first 7404 in the segments section.
I also pulled the chip before the 7404s on the digits section as it was only giving outputs of 1.65 and I thought that seemed odd. After pulling that I have the same readings. 2.5v from u5 and 1.65 going to the 7404s.
Any more ideas for me to check in to?

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