Sharp ZQ-6600

I have two of these. Both have buggered LCD screens. So I decided to document the hardware for posterity, since at the time (2023) Google has very little on the ZQ-6600.

Main PCB

The processor is an LH580011. This could be the great-grandson of the LH5801 in the PC-1500 maybe. There's an LH538NNU, which is a LH538700 1M x 8 Mask ROM (with maybe NNU the code for this specific mask -- I'm guessing here). They had enough space left for an alternative footprint for the ROM.

The SC51B240 would be the system interface to the keyboard and the LCD -- again, guessing here. Good luck with datasheets.

256 Kilobytes in two x TC518128 Pseudo-static RAM (basically dynamic RAM with built-in refresh -- even in 100uA standby mode) as well as 8K in an AT28C64 EEPROM.

The other side of the PCB is the keyboard matrix. This is at least a 4 layer PCB.

LCD PCB

There are two screws under the keyboard sticker that you need to remove to get here.

Fairly standard LCD drive circuitry, very similar to the 2 x 16 or 4 x 20 displays we all have on our PIC projects.

Mask ROM

I desoldered the ROM, soldered it to a socket to read it in my EXPRO. Had to write code to do it, of course. I confirmed that the pinouts match the LH538700, the /CE and /OE pins are definitely right, and the ROM image looks sane (i.e. the address lines are in the same order).

I'm not claiming it's pretty.

Gets the job done though LH538700.BIN.

PRODUCED BY SHARP Co. Masui Adachi Shimaoka SASSO SBC Shimada Yoshinaga