Turbobooster Plus schematic?

[wilykat]

Anyone got it?  I have mine but the RF shield is soldered on and I don't want to rip it apart to find out if it'd be possible to replicate save function on smaller scale for portable console.

I know there's SRAM (256KB I think) and capacitor for saving them. But I think there's more to these because I can see 2 IC chips labeled IC1 and IC3 (where's IC2?)

IC1 is marked NEC Japan D65006GFE08 and 9046KK00  I'm guessing the last one is date code (46th week of 1990) and other code, I tried to look for datasheet on the chip but there seems to be no D65006GFE008 and when I tried simplier number, the first 50 results Google gave me leads to site that says pay $xx for datasheet but doesn't even mention what kind of chip it is (scam probably) so I gave up on it and assumed it is either NEC secret or propriety chip for SRAM controlling.

IC3 looks like standard IC DIP and could be the SRAM. There's a fat looking green capacitor near IC3 that is probably used to power SRAM and keep data when the console's off.

[wilykat]

Aother view of the PCB:

[HercTNT]

hope you make progress. this has been talked about much in the mod section. having save function in a gt or express would be insanley cool.

[Duo_R]

Quick question on this since i never had a booster: how do you manage the memory? Does it have a boot up menu when no hucard is entered? Any screenshots of this?

Yes there are two smaller ICs under the metal shield.

[wilykat]

With a CD card inserted, at the CD slpash screen where it says press run to start, press select to get other option.

TG-16 and PCE (all non Duo models) still needs a card to run, even to run CD game or check the memory.

[Duo_R]

This is interesting,.didnt this come out before the CD unit? I guess NEC was counting on people not filling up the memory?

[wilykat]

I'm not sure what came first, the CD system or the memory backup unit.  Anyone familiar with PCE history might know if CD came first (with System 1.0) or if the memory only unit was available first.

Anyway since there seems to be no information, I went ahead and tried to take it apart.  NEC used way too much older on the RF shield.  I wasted over 6" of desoldering braid and still hadn't gotten the first tab free. So I dremel'd it off.

FL1 to FL4 are ferite core that seems in line with A/V out and power in.
LC1 to LC4 I'm not sure. Looks like ceramic caps but with 3 pins. 
L1 and L2 are empty spot for 2 pins inductors

C1 0.10 F 5.5v (yes, 0.1 farad, not microfarad, for SRAM)
C2 to C7 is not found, no board printing
C8 1uF 50v electrolyte caps
C9 1uF 50v electrolyte caps
C10 1uF 50v electrolyte caps
C11 is not found
C12 is 10uF 16v electrolyte caps
C13 47uF 16v electrolyte caps
C14 47uF 16v electrolyte caps
C15 10uF 16v electrolyte caps
C16 470uF 16v electrolyte caps

D1 looks like geranium diode, probably a basic diode
ZD1 zener diode, unknown voltage

Q1 A733 PNP Epitaxial silicon transistor
Q2 C2785 NPN silicon transtor
Q3 A953 PNP transistor
Q4 C2785 NPN silicon transtor
Q5 C2785 NPN silicon transtor

1 resistor network 4.7K ohm (10 pins to 1 common), next to IC2 for pull up or down resistors.

IC1 D65008GFEO8  (propriety chip? I still can't find this chip, I get either send $ for datasheet, not in stock, etc no actual free datasheet or even name of it)
IC2 74HC245 octal bus 3 states (likely used to float data bus when memory chip is not needed to prevent bus interference)
IC3 2048x8 bit SRAM 10nS
IC4 C358C low power dual op amp (probably for the sound)

image:

[wilykat]

In theory the whole thing or just the memory saves can be replicated if we can figure out IC1, the large chip near the SRAM chip

[MottZilla]

Wouldn't the better way to "figure it out" be to look up technical information on how it works in the system? I checked the only document I had on the PCE memory map and it didn't have any labeled or similar to "2kb Backup RAM". It might just be mapped at some particular address on the external bus. If you can find out where it is mapped and if it has any particular rules to how it is controlled you could figure out how to take some chips to map some memory in.

[HercTNT]

I thought charles mcdonald released a document covering all functions of the expansion pins. I remember seeing something on memory backup interface.

edit: i found this, not sure if it helps at all. this info is probably already on the site somewhere

http://www.hardwarebook.info/PC_Engine_Expansion

[wilykat]

Yes I know about the expansion pinout but it doesn't explain how the console interacts with SRAM.

And I've tried Google but I never found any detail on how they worked at all.