• Please review our updated Terms and Rules here

Mysterious board identify?

Muttley Black

Experienced Member
Joined
Aug 4, 2019
Messages
97
Location
Greece
Hello all.

I have this board for years. But never find an info about it. I am not sure if the TMS is actually Texas Instruments to be honest.

If you can help, I will appreciate it!

Thank you.

CC82302C-234C-45E9-A506-AE0E538B34BF.jpeg

E0653418-C499-4D68-A771-508FBF354567.jpeg
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
40,310
Location
Pacific Northwest, USA
I'm almost dead-certain that it's not TI. No silk-screening is going to make things harder to identify, particularly since the solder side isn't shown in your photos. I can make several guesses, but that won't help you with the PROM contents, not the contents of any programmable logic.
Your best bet is that someone recognizes this.
 

Bruce Tomlin

Experienced Member
Joined
Jan 6, 2010
Messages
164
Location
San Antonio, TX
Lack of a date on the board is also a problem, but I do notice that the DRAM chips are 18 pins. They could possibly be for 1M x 1 chips. 2M is pretty big for something using a 40-pin DIP CPU.

The other interesting thing is the lack of any kind of bus, just some 2x12 headers with .15" pin spacing. That implies some kind of industrial context.
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
40,310
Location
Pacific Northwest, USA
Could also be a board for a terminal or the like. Those 18 pin memory DIPs could also be for some inMOS 16K RAM for example. I guess one could bite the bullet and work out likely candidates for the 40 pin DIPs. and what appears to be 24 pin PROMs.

The device pads in the lower right corner is likely for a battery.
 
Last edited:

Muttley Black

Experienced Member
Joined
Aug 4, 2019
Messages
97
Location
Greece
It is weird that even with the "pl11013" I can’t find any info about it. I hope someone have seen one of this and post some info here. Should is better to move this post in a general discussion as it it is not a Texas Instruments product? Or it is?

Even with no date printed on the pcb, can we assume it?

Thank you all!
 
Last edited:

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
40,310
Location
Pacific Northwest, USA
I'd move it to general discussion. This doesn't look like a TI product at all.
It's not uncommon for the bare PCB to have a different part number than the completed assembly.

As for as a date goes, at a guess, I'd put this pre-1987, assuming that the 24 pin pads are for EPROMs. 28 pin EPROMs, when the size was justified, took over pretty quickly.

Can you post a photo of the other side of the board?
 

krebizfan

Veteran Member
Joined
May 23, 2009
Messages
5,550
Location
Connecticut
The only clue I can see as to what chips this board was intended for is the traces connecting the two 40-pin regions. I didn't find any pair of chips that had to be connected on those pins but there are a lot of 40 pin chips I have never used and have no documentation for.
 

Muttley Black

Experienced Member
Joined
Aug 4, 2019
Messages
97
Location
Greece
Thank you that you put "this" in general discussion. Or you going to put it? Cause i see it only in Texas Instruments thread.

Here is the solder side of the board. I can’t add my first post to drop it there so i do it here:

65CA33B2-EBE4-4BE4-A8AF-76AE8FA0E35F.jpeg
 
Last edited:

Bruce Tomlin

Experienced Member
Joined
Jan 6, 2010
Messages
164
Location
San Antonio, TX
Ah, the holes on the end are all wired differently, and both rows are connected. Looks like a backplane bus.

Anyhow, if it was TI, it would be obvious. They wouldn't miss a chance to put their name or logo somewhere.
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
40,310
Location
Pacific Northwest, USA
Here are my guesses now that we have the solder side in view. On the component side, the leftmost 40 pin IC appears to be an MC6800 or 6502. That's as far as I've gotten thus far. As far as the RAM array, probably 2147s.

Maybe the CBM or Apple folks can take over and fill in some blanks--I'm not much of a 6502 guy.
 
Last edited:

Bruce Tomlin

Experienced Member
Joined
Jan 6, 2010
Messages
164
Location
San Antonio, TX
The RAMs are definitely 2114. Pins 1-7, 15-17, 10 (A0-A9, WE) are all connected both ways, pins 11-14 (IO1-IO4) are only connected between every other row, and pin 8 (CS) is complicated. So 8K bytes total.

CPU is definitely a 6800 or 6502, ground on 20 and 40, Vcc on 8.
Pin 38 is NC on 6800, SO on 6502, and is tied to GND (normally should be tied to Vcc), so clearly a 6502.
And it bothers me that one of the 24-pin positions ties pin 1 to 24 and 23. I think those might be GND and it's a 6850. The 6850 data pins are on 15-22, and that looks right.
 
Last edited:

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
40,310
Location
Pacific Northwest, USA
I can fill in some of the jellybean TTL packages, but I'm not familiar with 65xx peripherals, so the 40 pin packages other than the CPU will be an uneducated guess on my part, but almost certain include a 6522 PIA.

As to "what the heck is it?" No real guesses.
 

RedskullDC

Member
Joined
Jun 6, 2014
Messages
25
Location
Dorrigo, NSW, Australia
That is a board designed for the OSI 48 Pin bus. (Ohio Scientific)

Not sure why it has dual rows, possibly to accommodate different types of header connectors?

Here is an OSI 470 disk controller for comparison.

You can see the beefy power traces (highlighted) match those on your board exactly:

OSI470-Top.jpg

Folks over at osiweb.org will be interested to see this.


Regards,
Red


Thank you that you put "this" in general discussion. Or you going to put it? Cause i see it only in Texas Instruments thread.

Here is the solder side of the board. I can’t add my first post to drop it there so i do it here:

View attachment 1244404
 

Muttley Black

Experienced Member
Joined
Aug 4, 2019
Messages
97
Location
Greece
It could be for Ohio because this board was in the same bag with two other Ohio bare boards, again with no components. The OSI 520 Rev B and the OSI 530 Rev C, both with 1977 date mark.

I have them many years.
 
Last edited:
Top