21 Apr
2009
21 Apr
'09
2:41 a.m.
I'm aware of that. Unless I've forgotten
something, no switching
supply is involved in these machines. Unless the supply that provides
HV to the CRT is a switcher. That's one of the reasons I ask. I'm
not too familiar with the guts of a CRT.
The HV portion is really a Tesla coil using the horizontal oscillator
for frequency input... and as far as I know would not be hurt by the
lower voltage. Rather, it's the main power supply that might be.
Yes, it takes weeks to get to operating voltage.
I'm not sure it
really counts as tedious, when most of what is involved is tweaking a
knob daily and checking for heat or smoke. Voltage and/or current
monitors would be nice, but who's got a working chart recorder these
days? I suppose I could turn an old laptop into one.
Well, that's excessive. It only takes, at most, a few hours to reform
the kinds of caps we're bound to encounter in these machines... as one
guy pointed out here a few weeks back.. this isn't vintage audio... and
without current limiting, it's an awfully crude method because IF
reformation is needed in any particular cap, and IF you raise the
voltage too fast anywhere along the way, excessive current is going to
give you pinholes in your cap's foil.
I want to stress again that if machines are powered on every several
years for a few hours, your oxide layer isn't going to be your main
concern... because that is one area where modern caps are superior....
Rather, your main concern is going to be dried out caps resulting from
excessive heat or just age.
Caps aging is a multivariable problem... and you really have to assess
your particular piece of equipment for all those variables before
proceeding on any kind of cap maintenance, testing, or replacement protocol.
jS
Eric