13 Aug
2006
13 Aug
'06
3:05 p.m.
I've done that sort of thing, on TVs, and what
you describe there ain't old.
TVs that were still using all vacuum tubes when I worked on them back in the
days I had my shop -- now they were OLD! Convergence used to be a real PITA,
because you had static convergence that was done by moving magnets on the
neck of the CRT (not to be confused with the purity magnets!) and then you
had dynamic convergence, which was typically 12-16 separate adjustments, all
of which interacted to some extent.
Actually, having grown up with delta-gun CRTs, I find them much easier to
set up than the in-line type. Tweaking presets is a lot easier than
tilting the yoke and hoping....
[...]
I used to try and fix monitors. The last time I had
one that I wanted working
I ended up tracking down some guy in the area who would work on them, taking
him 3 or 4 of the monitors that I had around, and telling him that he could
keep them if I got the one fixed that I wanted. As it turns out he didn't
fix it right, and I've not felt like being bothered to go back there and
hassle it since then. I did open that one up, but there was no way I was
going to attempt that repair. <shrug>
Why not? Admittedly modern monitors are horrible to work on, with one PCB
that's totally inaccessible....
The other thing is, to do a proper convergence needs a signal that's going to
give you a stable pattern, although I suspect that's easier to do with a
computer driving it than not, I had to buy a little generator for TVs back
Indeed. With a computer, it's trivial to generate a cross-hatch pattern
(the main one needed for convergence).
For TVs, you either buy/build a cross-hatch generator (I remember
building one from a kit about 15 years ago, it was only a handful of ICs,
one of which was a TV sync generator chain). Or you use a home computer,
suitably programmed. There were programs for the BBC micro, C64, etc,
published in the magazines.
Monitors are apparently moving into the "not
worth fixing" category any more.
To be fair, very little of the stuff we talk about in this list is 'worth
fixing'. Why spend hours/weeks restoring a PDP11 when a PC has a lot more
CPU power? Well, we all know the answer to that...
I feel that the original monitor (and disk drives [1], keyboard, etc)
are as much a part of the machine, particularly (in the case of the
monitor) on a workstation, as the CPU. Therefore, I'd want to repair the
monitor if at all possible (even if, say, I have to re-wind a transformer
to do so,,)
Now no-name SVGA monitors are another matter. I do _NOT_ want any of
thsoe, I don't repair them, etc.
-tony