Ok so it been 12 months since i have been in the repair room , Taken a Day just to clean it out !!!
Anyway I thought I would share an attempted repair that is sadly the main IC so i cant repair.
Ok so we have a clean ish Final Fight I purchased from ebay - It was being sold from a member on here though. It came with a dead A board that I will get around to looking at at some point.
Did my usual visual checks and the C board is bit mucky and black on some pins.
I fired this up with a good A board and the board fired up ok and sound and initial graphics looked ok but when the main screen showing the final fight kicked in it showed graphics issues :-
So i suspected either the main Background rom or the C board - The easiest way to test is with a known working one and luckily i had one. I fired it up with the working C board and everything was good. This sadly confirmed we had an issue with the C board.
Whipped the C board out and had a look under scope - did not look good :-
So time to get the soldering iron out and re solder/rework the lot. A tedious job and not for the faint hearted !
After the work i clean the whole board and its looking good enough now :-
Ok yeh i know i am NOT the best at these small IC's - I hate them ! My eyes and hands are not as good as they once were.
Image here just to show that having a microscope is very handy as I had not noticed i had caused this :-
Anyway had fingers crossed and fired the board up and .................
So at this point I am as sure as I can be that the soldering is ok - Although you can never be sure. At this point I have the option to remove the chip and reseat it but I didnt think this would fix the issue.
I then set about making an output document using the working C board. I do this on computer and then hand write & compare with the faulty one :-
Everything was fine apart from pin 158 - This pin was pulsing on the faulty C board but N/C(Floating) on the good board. This rang alarm bells as they should be the same. It seems that 158 is a reply from the main A board (As far as I can tell) but confirms that the information from the CPS-B-4 is incorrect and corrupt.
Unfortunately I can do no more unless I can either find a C board or get a replacement CPS-B-4.
Yeh sorry its not a repair but this is the sort of thing that I would look for when i started repairing to direct me so I am hoping this will help others in the future.
Sorry its a bit long winded as well , I shrunk it done the best I could.
Please feel free to leave comments as I always like to see what others think.
Dave.
P.S If you have a spare board then give me a shout as I need one ! lol
TheDaddy2021-04-05 15:25:27
Anyway I thought I would share an attempted repair that is sadly the main IC so i cant repair.
Ok so we have a clean ish Final Fight I purchased from ebay - It was being sold from a member on here though. It came with a dead A board that I will get around to looking at at some point.
Did my usual visual checks and the C board is bit mucky and black on some pins.
I fired this up with a good A board and the board fired up ok and sound and initial graphics looked ok but when the main screen showing the final fight kicked in it showed graphics issues :-
So i suspected either the main Background rom or the C board - The easiest way to test is with a known working one and luckily i had one. I fired it up with the working C board and everything was good. This sadly confirmed we had an issue with the C board.
Whipped the C board out and had a look under scope - did not look good :-
So time to get the soldering iron out and re solder/rework the lot. A tedious job and not for the faint hearted !
After the work i clean the whole board and its looking good enough now :-
Ok yeh i know i am NOT the best at these small IC's - I hate them ! My eyes and hands are not as good as they once were.
Image here just to show that having a microscope is very handy as I had not noticed i had caused this :-
Anyway had fingers crossed and fired the board up and .................
So at this point I am as sure as I can be that the soldering is ok - Although you can never be sure. At this point I have the option to remove the chip and reseat it but I didnt think this would fix the issue.
I then set about making an output document using the working C board. I do this on computer and then hand write & compare with the faulty one :-
Everything was fine apart from pin 158 - This pin was pulsing on the faulty C board but N/C(Floating) on the good board. This rang alarm bells as they should be the same. It seems that 158 is a reply from the main A board (As far as I can tell) but confirms that the information from the CPS-B-4 is incorrect and corrupt.
Unfortunately I can do no more unless I can either find a C board or get a replacement CPS-B-4.
Yeh sorry its not a repair but this is the sort of thing that I would look for when i started repairing to direct me so I am hoping this will help others in the future.
Sorry its a bit long winded as well , I shrunk it done the best I could.
Please feel free to leave comments as I always like to see what others think.
Dave.
P.S If you have a spare board then give me a shout as I need one ! lol
TheDaddy2021-04-05 15:25:27
