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Purpose of the "back up pcb" on a Taito g-net?

Kujako

Kujako

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Looking at getting a Taito g-net and doing the whole CF card conversion thing. However, I notice that on all of the cheap boards I can find the "back up pcb" is missing. This is the board that is adjacent to the PCMCIA daughter board that has three massive capacitors on it. I'm unclear on if this board is needed for some games or what it even does.

Any information would be appreciated. Thanks.
 
I too would like to know how/what the backup board does, I just bought my first gnet system but wasn't able to find one with one for a reasonable price. from that I can see in pictures it looks like a simple board... I see some cap, mosfet and two other ICs. It's hard to tell from low rez pics but I would imagine this would be a fairly easy board to replicate and potentially improve.
 
i heard it does not save high scores, but assists with loading faster or something according to @rewrite. essentially not worth the premium. if anyone has one i can repro it lol
 
advans14 said:
i heard it does not save high scores, but assists with loading faster or something according to @rewrite. essentially not worth the premium. if anyone has one i can repro it lol
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Y'know how when you turn on a game and the GNET counts down from 2305823508 to 0? It skips that.

But really, turn on cab, go walk and grab a drink, by the time you're back it's done. Not worth much of a $ premium for sure.

I'm 90% sure it doesn't backup scores.
 
I am still waiting for my gnet to arrive, so I guess I find out how long that'll be when it get here. If there some better pictures where I could read what everything is I would be will as well to try and repro it as well. Could save some people some$ who are g-net curious
 
I have a GNET without the backup board, and it only does the long bootup countdown when I swap over to a new game. If the game already in the internal flash matches what's in the cart slot then it boots up almost immediately after a quick check. It saves high score too, so I have no idea what functionality the backup daughterboard adds.
 
I do have one with the backup board (well, i think i do,lol) if i can help with anything please let me know.
 
_rm_ said:
I do have one with the backup board (well, i think i do,lol) if i can help with anything please let me know.
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Attached is the best picture I have found online, so if you were able to take a better picture of just the board itself that would be good. From this picture I can make out some of the IC part numbers except u3. I should be able to read a majority of the resistor band codes, my memory the best on those, so I would need to look them up as I go. This picture doesn't allow me the see the ratings of the capacitors, the bank zip tied to the back should be all the same. If I had to guess, 470uf for the bank and 200 for the smaller coupling one. The is also the cermaic capictors which should have the values printed on the sides but maybe some of the will become more obvious as it gets diagrammed out.
 

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I documented this system for MAME years ago, I should still have the images somewhere. Traveling just now but will take a look.
 
Sweet! Seems simple to repro. But i think the function depends on of its worth it or not. If anyone wants to donate one I can provide a free extra after reproducing.
 
I'm thinking, with those big caps, could it be they maintain voltage (for a couple of days or so) to a RAM after powering off?
 
I am curious as to what this PCB really does.

From the components it looks like it is supplying voltage to a section on the gnet. Next step would be to determine where the tracks go.
 
I’d like to see main-board photos from someone who has a backup pcb. My theory is that this pcb is useless unless your pcb came with it originally. I think they added components to the main pcb on the other version.
 
Maybe it’s purely power related like you sake. Looks like a few ic that send different voltages out. Perhaps you’re right. Maybe a satellite board to send auxiliary voltages.
 
advans14 said:
Caps dont work like that. Youd need batteries
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Can't batteries be seen as big capacitors? There are for sure systems using capacitors to save scores or settings over a few days. CPS2/Naomi have a super-cap (which is just a cap of higher capacity).
 
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