29 Aug
2010
29 Aug
'10
11:21 a.m.
Hi Tony
First=2C to determine the number of turns. These are flyback so
the collector ( or plate voltage ) would not be enough. You'd have to
measure the peak voltage on the collector ( or plate ) and then use
the known voltage of the second anode.
This would give you the turns ratio.
THis assumes you have a working flyback transformer of the same type.
Fine if there's somebody else with the same machine and the test gear to
make the mesurements, less fine otherwise.
Let me re-state the question. The horizotnal output stage was designed
once (I do not beleive for an instant that they simply tried random
numbers of turns and random component values). The horizontal output
stages of just aobut all manufacutrers seem to follow the same basic sort
of design. So presumably there is a way of desinging them. But I can't
find any book or web site that explains it. Is there one? [Suppose IU
wanted to make a nrew CRT-based monitor. How would I set about designing
the horizontal output stage).
Knowign how to design such a stage, I think it would be possible to come
up with a suitable flyback transformer -- not necessarily an exacy copy
of the original, but one that would workl -- for a defecting machine.
This would=2C of course need to be done on a working
coil.
Next to determine the wire sizes and the primary turns.
This is a distructive method. You just saw it perpendicular
to the turns. Counting the primary turns is usually easy
if the transformer is not potted. In this case=2C you'd need
Flyback transofmresw are almost always potted for insulation reasons...
and what do you mean by 'primary winding' (and how do you indentift it on
the core)? A lot of flybacks had a multi-tapped winidng connectinfg to a
suppl line through a diode; the collector of the output transistor; maybe
a diode or diode/capacitro to ground; various +ve and -ve outputs (via
diodes/capacitors), etc. I think tryuing to find the apporpirate bit of
that wininf if you've cut through the transformer would be hard to say
the least
to grind the ends on a belt sander until you can see
the
turns separately You should be able to see the primary
turns.
As far as a vacuum=2C just use an old bicycle pump with the
plunger and one-way valve turned around. An old cast
pressure cooker would work well enough as a vacuum
chamber ( never to be used again for cooking ).
Have you tried this? I am wondering just waht sort of vacuum is needed
for this.
Rigging a lathe with a counter and you can wind the
coil.
YEs, I've wound plenty of coils that way. But coils that have to stand
high voltages are a little harder. You need to be careful that you don't
ahve turns next to each other with a large votlage betweent them, or you
will get breakdown. It's a related problem to widing RF coils (where you
don;t want turns with large RF voltages betwene them due to stray
capacitance effects). You my well need to put the turns down in a
particualr order.
These are all things I think you can handle.
I am not convinced this is the whole story...
-tony