12 Dec
2004
12 Dec
'04
4:20 p.m.
Hiya
Three boards which I expect are from an SwTPc. Each
bears the SwTPc
logo somewhere in the component-side etch.
Well, that's easy then :-)
One I feel sure is a CPU board. It bears many DIPs,
all socketed (and
all sockets populated), a 7805 and four discrete transistors or similar
devices soldered in, and miscellanous two-terminal devices (resistors,
caps, a crystal, maybe some others I don't recognize). The "big chip"
is an MC6800P; I also see an HM46810P, an MC14411P, and a chip labeled
with the motorola logo and the text "SWTBUG 1.0" and a "7748" which I
imagine is a datecode. Everything else is in the 8- to 20-pin range.
On the card edge is a 50-pin single-row connector with slightly over
2.5 pins to the centimetre, with one pin space filled with plastic.
Yup, it's a CPU all right. SS-50 bus.
Next to the SwTPc logo is the text "MP-M". I
suspect the 7805s are
intended to have heatsinks which the board has been robbed of, probably
at the same time as the socketed chips were removed. This has a
card-edge connector apparently identical to that on the CPU board (just
above).
Yup, memory board.
A board which I feel sure is memory. It's marked
"MP-8M2" and has a
SPDT switch with the positions marked "WRT. PROTECT" and "NORMAL";
next
to one row of 8 DIPs is "UPPER 4K" and next to another is "LOWER 4K".
It also has two 7805s, each driving power to some of the chips - their
outputs aren't wired together. There is also a DIP bank of four
switches.
Yup, more memory.
The 30-pin card is an I/O card for the same box. The motherboard
ran the SS-50 bus, plus a decoder to eight SS-30 I/O sites, mem
mapped of course.
http://www.retro.co.za/6809/documents/ct-apr81.pdf
W