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twistedsymphony

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@sergiopolog and I started this discussion in the Interest Check thread, and I wanted to move it to it's own dedicated thread so that it doesn't get lost.

Why is this important? Because the upcoming CPS1 Multi will need a battery backed C-Board to be installed without some serious soldering. allowing us to use the quite common 92631C-6 C-Board will more than double the amount of compatible C-Boards out there.

The Two boards are nearly identical.
MVS Scans has some high resolution photos of these boards:
https://www.mvs-scans.com/index.php/CPS1_-_C_Board_90631C-5
https://www.mvs-scans.com/index.php/CPS1_-_C_Board_92631C-6

Note that the 90631C-5 in those photos has been modified for a desuicide (battery removed, and traces cut/wire added around the pin 41-46 area of the B-21)

A similar mod will likely need to be done to modify the 92631C-6 to act like a 90631C-5

about the second point, I need to check some notes I made when I was investigating all those C boards when I tried to get all the “universal keys” to be programmed in B-21 to act as any other B-XX (same thing that Undamned InfinikeyCps1 will do).
looking at pictures of the 906315C-5 and the 926315C-6 they look identical aside from-the silk-screened number-Resistors R1-R5 are not populated on the -6
-Diodes D1-D2 are not populated on the -6
-PAL1 is not populated on the -5


it'd be fantastic if the mod to make these compatible was as simple as installing these resistors and maybe a PAL.


EDIT
it looks like pins 42-46 are where most of the differences are. so some wire mods and trace cutting would be in order.
Okay,
I have this in my notes from a while ago:




Differences between 90631C-5 and 92631C-6


  • "C-6" lacks of D1, D2, R1, R2, R3, R4, R5, CX7 (rectifier circuit?)
  • Pin 45 y 46 are tied to GND in "C-5". They are tied to +5 in "C-6"
  • Pin 40 is tied to battery+ in "C-5"



So, a possible upgrade could be:



92631C-6 - Modification for running with battery:
  • Install D1 and D2 wth diodes (1N4148)
  • Install R1 and R2 with 102 resistors (1kOhm)
  • Install R3, R4 and R5 with 105 resistors (1MOhm)
  • Install CX7 capacitor (0.1 uF ??)
  • Tie Pin 40 to D1 catode (to supply battery power when game is switched off)
  • Pin 42: lift up and connect to CN19 (pin to program keys)
  • Pin 44: lift up and connect to CN20 (pin to program keys)
  • Pins 45 and 46: lift up and connect to GND (solder blob along Pin 47 for example, in order to set B-21 works in "battery mode")
Five first steps should not be necessary as battery wil be no longer needed in DS multicps1



Disclaimer: I didn't try it by myself, becuase I only have two 92631C-6 boards and I want them remain untoched but I'm happy to try it if I get another spare one.
To continue this discussion I don't think the above mentioned pins need to be "lifted" it looks like you could just as easily cut the traces.

with that said...

What we need now is someone to test this. Without a CPS1 Multi and without a battery I would think the only viable test method would be a C-Board infinity-key set running a modified 92631C-6 on a game that normally uses any battery backed B-21 C-Board
 
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Nebula

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I realized there is a typo on the second point in the "Differences between 90631C-5 and 92631C-6" paragraph on my quote from the other thread.

When I said:
  • Pin 44 y 45 are tied to GND in "C-5". They are tied to +5 in "C-6"
It should be:
  • Pin 45 y 46 are tied to GND in "C-5". They are tied to +5 in "C-6"

And then now it matches with the instructions below.

I'm gonna change my other post to let them clear and avoid confusions. Please, do it also here ;)


Regarding this:

To continue this discussion I don't think the above mentioned pins need to be "lifted" it looks like you could just as easily cut the traces.
IIRC, those traces go down the B-21 itself, so it's not possible to cut them directly without removing B-21, so that's why I chose the verb "lift" for those steps :rolleyes:


EDIT:
I found this picture:
6p33HPN.jpg











If you zoom-in in the 41-46 pin area, you can check that 45 and 46 pin traces sadly go down the custom chip, so lifting those pins I'm afraid that is inevitable
 
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Bigsingerdawg

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Thanks for putting this together, asked on the CPS1 thread since my set up has the right chip but no battery, if the below is just solder work and not the hot air work that was mentioned to be extremely difficult.

  • Pin 42: lift up and connect to CN19 (pin to program keys)
  • Pin 44: lift up and connect to CN20 (pin to program keys)
  • Pins 45 and 46: lift up and connect to GND (solder blob along Pin 47 for example, in order to set B-21 works in "battery mode")
 

twistedsymphony

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if the below is just solder work and not the hot air work that was mentioned to be extremely difficult.
you should be able to accomplish these modifications with a simple soldering iron, Still not the easiest task since you're still dealing with very fine pins, but it's far less difficult than trying to transplant the whole B21 chip.

if through hole soldering is a 1/10 difficulty and transplanting the B21 is a 9/10 difficulty then this would maybe be a 4/10
 

Bigsingerdawg

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Heck yeah, that's wonderful news. My guy a few hours away or I'm sure more people locally could handle for sure. TY
 

Nebula

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if the below is just solder work and not the hot air work that was mentioned to be extremely difficult.
you should be able to accomplish these modifications with a simple soldering iron, Still not the easiest task since you're still dealing with very fine pins, but it's far less difficult than trying to transplant the whole B21 chip.
if through hole soldering is a 1/10 difficulty and transplanting the B21 is a 9/10 difficulty then this would maybe be a 4/10
Agree. And you can easily revert these modifications at any time to put back it its original state
 
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