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So if one isn't using an existing C board, one can simply obtain the B21 IC and solder it and only it directly to the multi?
 
I've got B21 C boards but am unsure if they are battery based. Guessing there will be a visible battery somewhere if so?
 
There is also another battery backed C board: 90630C-4 used in three wonders. It is rarer to see, thought, as it is only used in that game.
If that PCB is battery based and has a B-21, then yes. If it's not battery based, you can desolder the B-21 and solder it on the multi PCB.
Nice! AFAIK that C board is only used for three wonders, it always has the B-21 installed on it no other B-XX variants
 
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I've got B21 C boards but am unsure if they are battery based. Guessing there will be a visible battery somewhere if so?
Essentially, the only C board populated with B-21 that is not battery based and then not compatible (at least without modifications) is 92631C-6 (from SF2 CE, HF, mega man, pang3...).
 
Most Conversion PCBs will fall into that last category as they typically used a non-battery-backed C-Board as a donor.
For people that couldn’t be confortable in desoldering SMD devices, transforming that incompatible C board into a valid one could be an option.

differences in that C board and mainly two:
  • It doesn’t have the voltage rectifier circuit used to cutting the power to be supplied from the battery when game is switched on.
  • Traces for programming B-21 keys (IIRC) are tied to GND.
“Reverting back” these things could make the C board compatible without the need of transplanting anything from board to board
 
“Reverting back” these things could make the C board compatible without the need of transplanting anything from board to board
If you know how to modify to restore the programming traces that would be a huge help as transplanting that chip is daunting.

I don't know that the battery circuit will need to be fixed since we will likely need to remove the battery anyway, I'm assuming that the multi will reflash the C-Board on boot much like the CPS2 multi does for the encryption keys.
 
Yeah I’m curious if it would be possible to “upgrade” a battery-less C board with a B-21. Seems like that could be easier than transferring the B-21 chip itself?
 
Yeah I’m curious if it would be possible to “upgrade” a battery-less C board with a B-21. Seems like that could be easier than transferring the B-21 chip itself?
You guys are probably right. Also I'm 100% sure that there will be some people will think that soldering of the B-21 in the multi is a doable job and they will end up breaking the kit. In any case...it's already there. Probably the best would be to make some reproductions of the 92641C-1 and then you can play with those. Notice that you don't need the battery at all as the keys are injected every time that you change the game.
Please keep it coming.
 
“Reverting back” these things could make the C board compatible without the need of transplanting anything from board to board
If you know how to modify to restore the programming traces that would be a huge help as transplanting that chip is daunting.
I don't know that the battery circuit will need to be fixed since we will likely need to remove the battery anyway, I'm assuming that the multi will reflash the C-Board on boot much like the CPS2 multi does for the encryption keys.
You are probably right and the first difference is not applicable as the battery presumably will not be necessary.

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).

I remember that is doesn’t be so much difficult and it could save from surgery those lovely C boards ^^
 
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.
 
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.
 
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This news is a blessing like salad dressing!☺️ I only got enough saved for one but seriously getting 2 wouldn't sound crazy in my mind. Thanks for the info.
 
Also I'm 100% sure that there will be some people will think that soldering of the B-21 in the multi is a doable job and they will end up breaking the kit.
I feel like this is going to be a really big issue. But I guess we just need to make sure that there are plenty of people available to do the installation.
 
Just to be clear, (i ran out of coffee today.. :( ) the B-21 transfer is only necessary for running CPS 1.5 games right? Not for regular CPS1 multi usage?
 
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