Konami Amidar

[jonhughes]

Decided to have a look at a n Amidar PCB I had in storage for a while because it was another Konami.

Game plays but sprites are missing - which was leaning towards something with ROMs 5D & 5F.

Checked all the inputs and outputs and I was getting signals. However, on closer inspection the ROMs were 27C32 not 27C16. I had a Scramble board very near by so swapped the ROMs on 5D & 5F over.

I then got this, hopefully ruling out any further problems the logic chips.

Put the Amidar ROMs in the programmer and they failed. Burned new ROMs for 5D and 5F and then had to burn new sound ROMs on the top board to restore the sound (there were 27C32 but bad without labels). I'm not sure this is now 100% but it could be 99%. There's a tiny square in the bottom right corner of the screen. No idea if this is normal, but it's slight.

I can live with it. A nice fast repair for a change.

 

[Van Diesel]

Great repair, Jon - I love that game

Van

 

[favouredson]

I'm not sure this is now 100% but it could be 99%. There's a tiny square in the bottom right corner of the screen. No idea if this is normal, but it's slight.

I can live with it. A nice fast repair for a change.

It's definitely not normal and your colours are wrong as well.

 

[Van Diesel]

Do you need a correct colour PROM?

Van
Van Diesel2020-10-05 22:54:47

 

[jonhughes]

I’m using a ROM board replacement kit from Phil on this. I’m going to check again because when I burned 5D and 5 F with a different ROM set I’m sure I noticed the colours change. Will investigate later today.

 

[Lurch666]

I would guess the square is because of bad video ram.

Possibly just one location is bad.

Can't remember which is the video ram on an amidar but if there's more than one and it's socketed try swapping them around to see if the bad block moves.