Help identify old i8085 board (supposedly Xerox)

[Tronix]

 

[MikeS]

Possibly a printer; those ROMs might be Postscript.

 

[Al Kossow]

Possibly a printer; those ROMs might be Postscript.

Not from Xerox in 1983 with an 8085 processor

Dumping the eproms might yield some useful strings

I can't tell from the picture if there are RS232 driver/receivers on the connector in the lower right.

The upper ones look like they are driving a peripheral interface

 

[Tronix]

Dumping the eproms might yield some useful strings

Unfortunately, they are soldered to the board.

I can't tell from the picture if there are RS232 driver/receivers on the connector in the lower right.

The upper ones look like they are driving a peripheral interface

Nope, his marking SN7406 and SP8404 (74LS08?), also I don't see USART IC on the board

 

[Tronix]

So, i desolder one EPROM from main board with strange marking:


I dumped it with help programmer as 2716. Dump in attachment.

 

[Tronix]

I desolder all chips from PCB marked "PAGED MMB 140P12268 A / 140S27530 B ED" and read it with programmer. Dumps in attachment.

 

[Al Kossow]

Based on the board design and date, it probably came out of the division in El Segundo that did the Star (Xerox 8010)
I'm guessing it is the print engine control board for their small printer (Model 4045). I have some service
info that I haven't scanned, let me dig it out and see if I can find anything that looks like that.

nope, not a 4045


the other thing is the board has a lot of eprom, but not much ram which wouldn't make sense for a laser printer

the eproms don't seem to have any text strings in them

 

[Tronix]

the other thing is the board has a lot of eprom, but not much ram which wouldn't make sense for a laser printer

the eproms don't seem to have any text strings in them

Thanks. The first dump from 2716 EPROM looks like 8085 code, first bytes mean jump to 0100h, then interrupts vector table, then startup code from 0100h location... Yes, no text strings in dumps... And don't remind raster FONTs, perhaps data bits and/or adress lines are bitstucked, i don't know...

So, PCB has two types of RAM - four TC5501P IC (256x4 sram) - 512 bytes total, and three TMM2016AP (2048x8 sram) - 6 Kb total. Also, IC marked 733W02274-1 near gold ceramic 40-pin controller look like 16/32 Kb SRAM, or maybe OTP EPROM. I try to desolder it and determine its purpose.

I plan to disassemble the board for spare 74LSxxx parts.

 

[MikeS]

Not from Xerox in 1983 with an 8085 processor

It was just a wild guess; I scrapped a printer years ago (Xerox IIRC, could have been NEC) with a similar size board and a daughterboard with 8 or 10 EPROMs containing the Postscript interpreter.

 

[Al Kossow]

It was just a wild guess; I scrapped a printer years ago (Xerox IIRC, could have been NEC) with a similar size board and a daughterboard with 8 or 10 EPROMs containing the Postscript interpreter.

in that time frame Adobe only had 68000 Postscript, and Xerox would NEVER have used it, since they had their own horse in the race (Interscript)

 

[Tronix]

BTW, any idea what kind of chip it is?

11,12,27 pin - GND
37 pin - VCC

 

[Tronix]

Chip marked 733W02274-1 isn't SRAM or OTP EPROM,
pin 7,8,21 - GND
pin 27 - VCC

 

[Chuck(G)]

Both are most likely custom parts.

Good luck in finding datasheets.

 

[Tronix]

Both are most likely custom parts.

Good luck in finding datasheets.

Yes, its ASIC from Semiconix (SMX Semiconductor GOLD CHIP TECHNOLOGY™). Xerox located in Palo Alto, SMX in Santa Clara, California, so they are neighbors.
Unfortunately, the chips are sent to the shelf, without the possibility of use in my homebrew CPU devices.

 

[Chuck(G)]

Problem is that the chips are dated 1984 and Semiconix has been in existence only since 1999. I suspect that the story is a bit more complex. Could possibly be HTE Labs, but that's cutting it close.

 

[Dwight Elvey]

They all seem to start with 733W I suspect the 733 may be a model number.
Dwight

 

[MikeS]

in that time frame Adobe only had 68000 Postscript, and Xerox would NEVER have used it, since they had their own horse in the race (Interscript)

You're right of course, it had a 68000 and was probably a NEC after all. Should have looked more closely but that ROM board looked very similar.