Snips:
Looks like a problem with the power supply filter capacitor.
Problem has been traced to the +350VDC supply, which has, under
load, a
large ripple (before the main relay actuates, ripple is lots
lower). This
oscillogram (sorry for the bad focusing of my picture) shows the AC
voltage
just after the rectifying diodes of the 350VDC supply (so it is NOT
the
regulated voltage):
(LINE frequency in Spain is 50Hz)
I'm looking at the schematic of the 545A, and I suspect that the 545B has
the same 350V supply. The (silicon) bridge rectifier feeds the 125uF
reservoir capacitor through two ten-ohm 1W resistors in parallel. It also
has an 82k resistor in parallel.
So check that the 10-ohm resistors are present and measure correctly, and
the same with the 82k.
Are you working from a schematic, BTW, or diagnosing blind?
Craig
