16 Aug
2008
16 Aug
'08
1:52 a.m.
Rick Bensene wrote:
Speaking of the PC-04 Paper Tape Reader/Punch, I have
one for my PDP 8/e system, but one of the ten phototransistors in the monolithic array is
shorted, making it pretty useless for reading tapes. It punches tapes fine.
There are ten phototransistors because eight are used for each of the channels of the
tape, one is used to sense the feed holes for clocking purposes, and the last is a
"end of tape" sensor. Unfortunately, since the phototransistors are in a
monolithic (single) package, I can't just replace the bad phototransistor or
re-arrange them to take the "tape out" one (which I could manage wtihout, I
suppose) and use it to replace the bad channel phototransistor.
Read the tape, flip it upside down, read it again, flip the bits, merge.
Gordon