pac / ms pac prom 7F contents

andrew96

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Hi

I read from posts on the net that the 7F colour prom contains different data for pac and ms pac.

so my question is does anyone know where i can get the files for each of the 7F proms for the 2 games? does someone have a download link?
I have a ms pac where the data D6 line is stuck at 0v so impossible to read out the data!

many thanks in advance
Andrew
 
thanks Riptor thats good! whats in my mind now is, why when midway issued the upgrade kit of proms for pac to mspac did they include 4E and 7F if they were not needed, i can't see them bothering to include them if they were the same as they would save the costs of the proms.

cheers
Andrew
 
I dont know that they did. I can assure you they are the same. The pac plus kit came with the proms since they were different.
 
thats brill! many thanks for that info, i had thought they were different, the reason is i have a jamma bootleg ms pac i bought broken and after getting it working found the colours were all wrong, on investigation i found D6 was missing from the equivalent position of the 7F prom, so took the chip out and read it, well the read did not match the pac rom at all! only the first 4 entrys were the same, rest was different! thats why i assumed it was different, then i discovered they swap the green and blue on the jamma bootleg pinouts for this board! put them right, made up a equivalent to go in place of the 82s123 (my programmer won't do the 82s123 so used a gal16V8 which it will program), programmed to act the same as the 82s123 chip with the pac rom data, put it all together and BINGO! all sucessfull! board now works with the correct colours!!


So many thanks for the info Riptor, it was indeed very usefull to know they were the same and indeed it has worked a treat! i am very pleased!

for those that dont know already, here is the site that helped me make a equivalent to the 82s123, i used and modified it for a GAL16v8 as thats what i had laying around on a old computer board of somekind! http://www.retroclinic.com/leopardcats/galprom/galprom.htm

thanks again
Andrew
 
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Yes, alot of the jamma bootleg boards have the colors pinned out incorrect. They also dont run the video ground out to the edge connector so depending on if the video ground is tied in on the harness you might have issues there also.
I have seen a few bootlegs where they used Gals in place of the proms.
 
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Cheers Riptor, indeed the jamma board i have also does not have the monitor earth......

I have also got hold of more of the exact same Jamma bootleg boards, the problem is the color pallet prom i thought was bad with no D7 output (all 0's) and corrupted data appears to be the same on the second same jamma board! so the 82S123N prom is not faulty after all??

attached is the midway 7F prom read and the results obtained from 2 jamma boards, (1)why is there the difference? (2) What is the meaning of the data in the locations 10 to 1F? can anyone help??

attached is the differences found

cheers
Andrew
 

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