Hello, I had this monitor from some time, it was part of a medical device that
was full of boards, it provided heart rate, respiratory info, and other things.
The boards are from late 70's, it was scrapped and I extracted the boards
many years ago.
What remains is this nice scope-like monitor:
these are the controls, it has two channels:
let's open it, from behind on the left there is the board that connects to external world,
from there pass the supplies and the signals, inside on the left there is the "backplane",
a board that connects the amplifiers and the sawtooth generator; on the right there are
the power supply boards: a low voltage preregulator, a medium voltage board and the
high voltage transformer
A closeup of backplane, we can see the needed voltages written on it:
This is the side, there are the power supply boards, and the side of the crt,
this one is slightly unusual: it is an electromagnetic deflection device, with
vector output, pratically a slow cheap oscilloscope.
this is the preregulator, it generates +12 -12 and +5V from tree input
voltages, I used simply +-18V to power it up, the NEC I4305 and I4312
seem Nec's 78xx equivalents, they are boosted by a pair of transistors,
should be 2SB512 and 2SD389, are current limited by the 0,47ohm
power resistors and small transistors:
more to follow...