I recently bought a bare PCB from a friend who found an entire box of them. The box is marked as shipped from Synertek in 1978. The layout mostly follows the SYM-1 down to most of the part locations and part numbers, but varies from that board in key ways. I'm aware that Synertek advertised the SM-100, which is an OEM variant of the SYM-1. I'm fairly confident this board is one. Finding SM-100 specific information is near impossible though. It appears this blank board may be a super rare find. The board is marked H-4932-XA. Lower down on the right, when I hold it up to light, I can see what appears to say "don" in large faint arialish black letters, but given the context, I bet it's actually "dan" (Dan Floyd).

Key differences from SYM-1:
- All bus connectors are IDC instead of card edge
- No on board Keypad space, IDC connector spot present
- All 6 7-seg displays have their own IDC connector spot
- 2nd row for RAM chips!!

I'm in the process of going over the SYM-1 schematic to correlate a parts list (No help on this please! This is a challenge to myself!). My plan is to build this thing. How much will be OEM time appropriate parts is questionable for my budget, but I do plan on using all sockets in EVERY slot so it can be changed later if desired. It probably won't use period components other than maybe transistors, if I can find them, anyways, so there's that. I also plan to document everything and create schematics. I might YouTube the process. There's not much on the Tubes right now documenting these things.

Now, here's the juiciest stuff. The box these boards were in was sent to Tektronix (name redacted for now while I research that aspect). What the blazes was Tektronix doing with a stack of these bare boards in 1978?! The only thing I can possibly think of based on their product catalog is maybe playing with it for the 4050 graphic station series? That kinda makes sense considering the SYM-1 can be changed to a 6809 and the Tektronix 4051 was 6800 based originally. Yet, that theory doesn't mesh with reality that they released the 4052 in 1978 with AMD 2901 architecture. Any other theories?

Enjoy the bare board in all it's glory.

Cool!

It's too bad that most all of the information regarding the MOD-69 is lost. Does anyone have one of these? Maybe we could reverse engineer it? The most important things would be a copy of the ROM and a listing for the PROM. The PROM could be replaced with a GAL or something similar.

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Bill

In trying to confirm which board this is, I could find anything on the /68, /69, or SM-100 versions of the SYM-1 to confirm anything. The distinct lack of Synertek silkscreen logos and the fact that it was sent to Tektronix in bulk leads me think it's an SM-100 over a /69, but without documents it's all guesswork.

This thread might be handy: http://forum.6502.org/viewtopic.php?f=3&t=4359

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Bill

(welcome, CHERIJO! An interesting find.)