what would case this issue?

i am running a Amiga mother board with a game daughter board i have correct voltage from power supply i am thinking defective game rom? i have garbage over game image not covering game image,start up game image is perfect....
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Game daughter board? What is that?

And what motherboard is it? A500?
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the Amiga board is in a arcade game called UpScope, it runs off a amiga power supply and mother board and the game roms are on a daughter board and 3 roms are on the mother board, i found a 2nd Amiga Pcb that works halfway, all i have is 321049-01 REV 6 I will post pic of board not sure what model it is
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pic of game image

Attached: 000_0001.jpg (199.2 KB)

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Cool. I've known about the Up Scope arcade machine for years but never seen one.

This arcade machine is based upon an Amiga motherboard plus a specially designed EPROM daughter board which contains the game roms.

The earlier versions used an Amiga A1000 motherboard, which your one does looking at your motherboard pictures, and later ones used an A500 motherboard. So you could try a different A1000 or A500 motherboard and see if that works. I think it needs a 1.2 or 1.3 kickstart rom.

There is an arcade machine owners group with 6 members owning this machines, so one of them might be able to help you get it working correctly. The link is: http://www.arcade-museum.com/members...?klov_id=10271

Does yours look like this?

upscope2.jpg

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Taking with some people on another forum they have given the following ideas to test it out.

The initial thinking is like you that there could be a problem with the rom daughter board.

However you can also rule out if there is an issue with the main Amiga A1000 motherboard. If you can find a space Amiga A500 or A1000. A500's can be picked up very cheaply these days for around £10/$10. You will also need some Amiga floppy disks.

I'm assuming the arcade machine's monitor is connected to the Amiga's RGB port? If so we can use this as it is to test. First disconnect the daughterboard. Now take the floppy drive and cable from the A500 and connect it up to the A1000 motherboard. And finally boot the A1000 motherboard. If it boots correctly you should be seeing the Kickstart rom boot screen asking for a disk to be inserted. To fully test you will need some Amiga floppy games. Once you have a couple boot these up and see what happens. If you still get graphics corruption then it is a problem with the motherboard and not the daughter board. If however everything is OK then it is the daughterboard.

How does the daughterboard connect to the Amiga motherboard? Parallel port? If so you can try an A500 motherboard instead with it, but you will need a gender changer to get it to plug in.

Hope that helps.

If you need any Amiga floppy disks for testing let me know and I can do you a couple of copies and post them to you.
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Thank you for the info and help, here is a pic of the set up, i have no hardware for this board.

Attached: 000_0002.jpg (134.7 KB)

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Ah, so it actually has 2 daughter boards. One connected to the Amiga's sidecar expansion bus, and the other connected to the Amiga's Parallel port.
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Some more suggestions for you to try (from a friend):

Originally Posted by :
first thing I would do is take a magnifying Glass and inspect the whole motherboard for anything that looks out of the ordinary (Caps) burn lines etc.
Yes, its a slow an Tedious job, but the A1k motherboard (NTSC) is kind of a "primitive" PCB and looks to be somewhat hand built. I can't tell buy the picture if it is a reflection but I have circle a chip that looks weird.also check under the metal cover

Second, the ROM's could have experienced "Bit" Rot after all these years. I am not sure how you could check this without having a "Clean" code, but I know that some EPROMS can be subjected to this.

This is the image with the areas circled that they think need to be especially checked.

areas_of_board.jpg

Finally, where are you located? Someone in Canada has said they have a couple of spare Amiga A1000 motherboards that you could try to see if that fixes it.

Another suggestion:

Originally Posted by :
Has he tested the daughterboard is correctly connected and the roms are in seated in place etc? Those defects look to me the sort of thing you would associate with a wonky rom connection in a typical ROM loading arcade machine.

Hope some of these suggestions help you.

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i took the lid off and took a look and could not find nothing burnt, the chip has the marking removed from the top on the other circle, i will have to look further,i am located in Connecticut and would like to find a working A1000 pcb. thanks
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