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View Full Version : Challenge - What mini (probably) did these logic boards come from?



billdeg
January 3rd, 2013, 01:46 PM
http://vintagecomputer.net/pictures/2013/mystery_logic-bd/thm_DR240_RA240-2_front.jpg
Can you guess what computer these logic boards came from?

The only thing I can say for sure is
1) They're not from a Digital Equip Corp computer that I have ever seen (not the right size)
2) The Philco PD993659 chips have a silscreen date of 1968, 17th and 18th weeks.
3) These boards are exactly 14 cm tall (not including the handles)

More pictures:
http://vintagecomputer.net/browse_thread.cfm?id=499

NeXT
January 3rd, 2013, 04:14 PM
There's no way in hell those CAN'T be flip chips.

billdeg
January 3rd, 2013, 04:42 PM
They're not. Too tall

NeXT
January 3rd, 2013, 05:34 PM
In comparison:

http://farm4.staticflickr.com/3336/3522381833_2be0039dd2.jpg

Hmm, you're right. The edge connector keying at least is different.

billdeg
January 4th, 2013, 06:30 PM
Does anyone have a DataGeneral logic chip to compare with? Both the mystery board and the FLIP CHIP (which is slightly shorter and thinner) have 18 pins on each side. What else would have 18 pins from 1968-69?

Chuck(G)
January 4th, 2013, 06:57 PM
Bill, can you post a couple of photos of the reverse side of these?

billdeg
January 4th, 2013, 07:06 PM
Oops i forgot to post a link from my site to the rear pic

http://vintagecomputer.net/pictures/2013/mystery_logic-bd/


http://vintagecomputer.net/pictures/2013/mystery_logic-bd/DR240_RA240-2_back.jpg

Chuck(G)
January 5th, 2013, 12:51 AM
I believe that the PD993659 is a DTL hex inverter, equivalent to an MC836L. Pinout similar to a 7404. The traces would seem to verify that.

My suspicion is that given the very limited amount of logic on each board, that they're not part of a computer at all. Perhaps some industrial control gear.