TurboBooster Plus technical question

I wanted to build a portable system using CoreGrafx, region mod, LCD, and memory for game saves. Since there seems to be no information on the memory save function of TB-Plus or CD system, 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:

 

What's the question?

 

Question: what is IC1 function? I couldn't find the datasheet or any other information so I can't tell how it is supposed to work in TurboBooster Plus. I'm guessing it's to connect SRAM to the system and managing the file library.

 

Probably "What does IC1 do?" or "What do LC1-4 do?".

 

It's a NEC CMOS gate array (custom logic chip). Most likely it was originally designed for the IFU or something more complicated, and here is simply being used for address decoding, memory locking.

The SRAM is more likely to be 100 ns not 10 ns.

The '245 is probably not for the SRAM (almost all memory has internal tri-state buffers), as you noticed the resistor network is next to it so it's some kind of discrete register that for whatever reason interfaces to open-collector outputs. No idea where the 8 signals would come from.

The C358C = NEC made LM358, definitely for audio