(Topic ID: 281764)

Eight Ball display issues

By mike53153

3 years ago


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  • 13 posts
  • 5 Pinsiders participating
  • Latest reply 3 years ago by Billc479
  • Topic is favorited by 1 Pinsider

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AS-2518-17 (resized).jpg

#1 3 years ago

Hi all-

I have a Bally Eight Ball machine that has an issue. It started out with a couple of the score displays flickering occasionally, then after about 30-50 plays the scores went out completely along with the credit and ball # display. Everything else is working fine.

MPU is a 2518-17 and solenoid driver board is 2518-22.

Visible inspection the fuses look fine.

Looking for direction on troubleshooting.

Thanks in advance,
Mike

#2 3 years ago

It's either a cold solder in the general area where the J1 connector is. All those resistors / capacitors and the J1 connector itself on the MPU board (2518-17).

But most likely chip U20 as died. It might be on a socket. It's a "4502" or a "MC14502B" a hex buffer/inverter. (Don't mix up with part number MC145028 instead , which is a decoder (last digit is EIGHT instead of B)). It probably isn't U19 at fault ("4011" or "MC14011B" , Quad 2−Input NAND Gate) but one gate is used in the display logic so it's possible.

These parts cost under a dollar each. If U20 isn't on a socket, you should install one after removing the chip.

#3 3 years ago

With the machine on, do you still see the glow underneath each of the digits on the displays? If not you may have lost the display high voltage to the displays.
The solenoid driver board has a small fuse for the high voltage supply - check that it hasn't blown.

#4 3 years ago

Thanks for the responses. I don't have any glow underneath any of the digits. Pics attached of MPU and Driver boards.
I have a multitester, just don't have any direction on what to test. If guidance can be given on what to test and what tests should show i'd be eager to learn.
Also, i do have good batteries in holder coming off lower leads on MPU board and solders are good.

Thanks again for any help given.

AS-2518-17 (resized).jpgAS-2518-17 (resized).jpgAS-2518-22 (resized).jpgAS-2518-22 (resized).jpg

#5 3 years ago

Since you don't have any glow at the bottom of the displays, you have lost your high voltage. Refer to Pinwiki for help. You can test TP1 on the display - you should see around 190 VDC. You can also check the test points on the SDB. Be careful - 240VDC bites hard. (Ask me how I know!!)

You should also test your rectifier board to verify those voltages are good.

Let us know.

1 week later
#6 3 years ago

So i've done some testing and looking for advice. I tested rectifier board and all fuses and test points are good. I also tested the fuse on SDB and that's good as well.
The solenoid driver board (as2518-22) test results were not good. TP4 test showed 261v but TP2 was 0.
With TP2 at 0 that's obviously a problem. Outside of replacing the SDB can anyone guide me on repairing my current board? I searched pinwiki but it only advises on checking TP2 but not what to do with a reading of 0.
Thanks in advance for any help given.

#7 3 years ago

Have you looked at the schematic for the SDB? Go to IPDB.org and download it.

Look specifically at the 190 VDC regulator section. There are some voltages there that will help on troubleshooting. Compare and report what you have.

#8 3 years ago

ok so i reviewed the 190 vdc regulator section like you suggested and at this point i'm in over my head. Testing individual components in a high voltage area is beyond my expertise.

With that said i'm looking for opinions. Based on what my testing above shows (261V at TP4 but 0 at TP2) and the fact that outside of this all other aspects of the machine is working fine, is it a fair assumption that the SDB is my culprit?

If so i'm comfortable with purchasing a replacement SDB board. I see Alltek sells one for $149.

Thanks again for any help/advice given

#9 3 years ago

Since you don't have any voltage at TP2, it is a safe assumption that the SDB is the culprit. A new Altek board will last for quite awhile, but there are people out there who will repair the current SDB. Along with repairing the high voltage section, they will also install new filter caps (The big sized capacitors) during the repair.

I'm not sure of the cost, but you can try to contact people who do that work. Chris Hibler comes to mind - he's on the site often. Whatever you do, don't throw away the old board. It is repairable.

#10 3 years ago

Get a new SDB from alltek and minimize your problems down the road unless you want to get into board repair

#11 3 years ago

Thanks for all the advice. I've gone ahead and ordered a SDB from Alltek and will report back once received and installed.

#12 3 years ago

Hi all-

Well, i got my new SDB board today and am happy to say my machines alive! Thanks to all who gave their thoughts and advice!

#13 3 years ago

Excellent. Enjoy the game. When you get a chance, please mark the thread as resolved.

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