looking for A board 89626-4 (cps1.5)
- Thread starter roy
- Start date
I think @sheep_nova is selling NOS cps1.5 A-boards for under $100.
Telpherion
Student
I always had the doubt about if is possible to replace this board on a CPS 1.5 with a A board of 12 Mhz from CPS1... maybe pulling the audio components? Any expert here? 
ran out
nice ideaI always had the doubt about if is possible to replace this board on a CPS 1.5 with a A board of 12 Mhz from CPS1... maybe pulling the audio components? Any expert here?
i will try to check it visually but its not enough
Bokoshi
Beginner
Definately possible,I always had the doubt about if is possible to replace this board on a CPS 1.5 with a A board of 12 Mhz from CPS1... maybe pulling the audio components? Any expert here?
I did it the other way around, converted a CPS1.5 by moving all the audio compoents to make a standard one with 12mhz.
The PRG1 PAL chip is different so you will need to program a new one with PRG2 data for a CPS1.5 board
Bokoshi
Beginner
Not entirely sure as I did it the other way around and added the missing components to the CPS1.5 A board.
You may be able to get away with leaving all the sound circuit intact and just change the PRG1 PAL to the PRG2 PAL from your old board and remove the SOU1 PAL chip from the A board.
I would give that a try first before you start removing any sound related components. That way you can reverse it if you want to use it for another rom set.
I would try it for you but i'm having issues trying to desuicide my Qsound/C boards.
You may be able to get away with leaving all the sound circuit intact and just change the PRG1 PAL to the PRG2 PAL from your old board and remove the SOU1 PAL chip from the A board.
I would give that a try first before you start removing any sound related components. That way you can reverse it if you want to use it for another rom set.
I would try it for you but i'm having issues trying to desuicide my Qsound/C boards.
capcomFan
Beginner
Do you really have to remove the sound circuits from the CPS1 A-board to use it as the A-board motherboard on a CPS1.5 stack?
I would think the CPS1.5 game software programs would not use that part of the CPS1 A-board since the sound is done through the Q-sound D-board.
I don't have any CPS1.5 to try it out though.
I would think the CPS1.5 game software programs would not use that part of the CPS1 A-board since the sound is done through the Q-sound D-board.
I don't have any CPS1.5 to try it out though.
A
Apocalypse
Might be some conflict, IIRC accessing sound on a A-board or D-board is done through the same address range.
so, would you say cleaning up the cps1 sound components will do the job?
Bokoshi
Beginner
capcomFan
Beginner
Good point. If the software is accessing the address range mapped to two different hardware, that could be problematic and lead to conflicts. I wonder what actually happens though in that case if you only take the audio out from the RCA connectors.
Any knowledgeable CPS-1 peeps able to chime in on this. If I remove the SOU1 PAL is that suffice to use a Dash Board in a CPS-1 stack without removing the audio section?
NOTE: This is the “fix” or repair currently on the A-board. Could have been done by factory or operator - halt pin of the z80 to ground. A genuine PRG2 PAL is already in place FWIW. Seems to be working fine. Played through the game multiple times. Just wondering what (if any) adverse affects might occur if I just run with this solution.
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