(Topic ID: 207022)

Shaq Attaq - EPROM CHECKSUM FF-12


By scampcamp

2 years ago



Topic Stats

  • 11 posts
  • 4 Pinsiders participating
  • Latest reply 2 years ago by MarAlb
  • No one calls this topic a favorite

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#1 2 years ago

When I power on Shaq Attaq it says EPROM CHECKSUM FF-12

Does this tell me the FF-12 EPROM that's labeled in the manual is bad? Thank you.

#2 2 years ago

.

#3 2 years ago
Quoted from scampcamp:

When I power on Shaq Attaq it says EPROM CHECKSUM FF-12
Does this tell me the FF-12 EPROM that's labeled in the manual is bad? Thank you.

Are you having an actual problem with the game? Or just wondering what a checksum is for?

A checksum is just a calculation of all the game rom's data that results in a short alphanumeric code. If there's an error in the data, the checksum won't match the expected value.

#4 2 years ago

$FF12 is the checksum from a shaq revision 5 gamerom. Everything is fine here and you are running the latest revision. Gott system 3 is Always showing the checksum after powering up.

#5 2 years ago
Quoted from MarAlb:

$FF12 is the checksum from a shaq revision 5 gamerom. Everything is fine here and you are running the latest revision. Gott system 3 is Always showing the checksum after powering up.

Ok great, thank you very much.

I am trying to figure out why the loud buzz from the under cabinet speaker. A friend said it may be capacitors on sound board or bad ground somewhere.

How do I use the dvm to find a bad ground? Do I need to test every connection? Thanks

#6 2 years ago

The 2 big capacitors on the auxiliary power supply are often causing this.

#7 2 years ago
Quoted from MarAlb:

The 2 big capacitors on the auxiliary power supply are often causing this.

Thanks.. great idea! GRUMPY stopped by & showed me how to spot electrolytics by seeing a "+" next to the part on the schematic.

#8 2 years ago
Quoted from MarAlb:

The 2 big capacitors on the auxiliary power supply are often causing this.

I changed the 2... 10,000 mfd & 25 v capacitors on the auxiliary board tonight but it didn't help at all. Any other ideas? Thank you. It's pretty loud and annoying.

#9 2 years ago
Quoted from scampcamp:

I changed the 2... 10,000 mfd & 25 v capacitors on the auxiliary board tonight but it didn't help at all. Any other ideas? Thank you. It's pretty loud and annoying.

Not really. Any change in the humming? Did the plated holes survive when removing the old snap in caps? Pretty easy to break them and when this happen you will loos continuity between top and bottom side of the circuitboard.

Are both speaker humming?

#10 2 years ago
Quoted from MarAlb:

Not really. Any change in the humming? Did the plated holes survive when removing the old snap in caps? Pretty easy to break them and when this happen you will loos continuity between top and bottom side of the circuitboard.
Are both speaker humming?

The capacitors came out & went in ok. The only hum is from the bottom under cabinet speaker...

#11 2 years ago

Can you measure the ripple voltage over capacitors C7 or C17 and C8 or C18 with your voltmeter in AC mode?

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