Check the filter caps in the power supply. You've got a terrific scope.
With a little patience and a few caps you'll be up and running.

The erratic sweep could be caused bt dirty contacts on the sweep switch.

Steve

RB wrote in message
...
Hi....recently I picked up an old Tek 475 200Mhz scope not working
I managed to get a full service manual for it but have had no luck getting
it running.

The +50 Volt rail (which I belive all other rails are derived from) is
perfect, as is the 110V, +15, +5 rails.

The negative rails are out, the -8Volt rail reads -6 volts but the -15
Volt
rail is way out at -23 volts.

Im not an expert with this stuff but like to have a go, it would be a
shame
to chuck it out.

Its really annoying me because the schematic for the -15 volt supply
"looks"
so simple, Ive checked caps, all resistors, transistors and even replaced
the IC (MC1458) with no change at all.

The CRT works fine, lots of brightness, the vertical amps both appear fine
but the timebase is werid, some (lower) ranges wont display a trace at all
and the higher ranges show multiple horizontal line (with no input) and
the
trace "curves" to the left hand side of the screen.

If I apply the cal signal input I can see the square wave but triggering
is
erratic, reminds me of my first "KnightKit" scope I got when I was a kid
that used a thyratron in the timebase.

Info/parts are a little scarce in this part of the world (Australia)

Does anyone have any hints/suggestions????
Thanks