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Two sides of the same card. Epoxy, silver and gold.
13 times the same circuit.
Germanium transistors (black) OC140 and OC47 (PNP and NPN couples)
TO5 transistors (metal) TI 2N1304 and 2N1309 (PNP and NPN couples)
Circuit dimensions: 32 cm x 13 cm
A look on these transistors, give that they are not conventional transistors.
It is possible to exchange emittor and collector. They can operate in inverse mode!
Is that a prelude to DTL or TTL familly?
The beautifull card contains 13 OC140, 13 OC47, 13 2N1304 and 13 2N1309
and 26 zeners (18v and 6.2v)
This card is a card to maintain computers. Seems to be a 12 or 13 bits D/A converter.
I have specifications of these transistors (very detailed for TI one. ed 1960)
On some other pcb, there are no date-code on.