Motorola ts907 low hv

[Username1]

That Motorola schematic has some good additional information on it.... It would be cool
to know if those voltages are there, and correct. I was wondering if the focus voltage
is correct, and in the range that is printed on the Sams.... Can you turn the focus
coil and have a range of 4.3KV to 5.2KV ? I know with a HV Probe you will not
see much resolution, but it may tell you if things are OK enough to not
worry about that part of the circuit. Not sure how you would check
that Plus & Minus 500V P-P - I guess you can give it a try
with DVM and see what happens......

Also for L42 getting hot, you know each coil & Cap are a tuned circuit, If there is something
wrong, it may be peaking at a poor point and creating too much power.

All I can think of right now would be to check focus voltage as best you can.
Since the flyback was removed, it may be a good idea to try and see as best you
can that the pins that go where you think they go have the right resistance on
them as best as you can determine.

Take a picture, several pictures, of the flyback wiring, then disconnect all the wires,
measure the resistance of all the pins as you see them using both schematics, and
try and determine if it's wired correctly. You may also want to check resistance
from one isolated winding to another, This confirms no short between windings
and that they are wired correctly inside the transformer.... Since you have 2
Flyback transformers, you can compare between the two.....

My thinking is that since that flyback has pins that are tied to components and then
back to other parts of the flyback, that if a wire is not connected right, then voltage
may be fed to, or from one section out of phase, and causing problems, possibly
even heat on L42.

Does the flyback run hot?

I'm not sure I would switch any wires unless you have real good cause to do so,
you don't want to make anything worse....

With that coil measuring a higher resistance, it may be because it's been hot, and
starting to change because of that.... Or since there are differences on the resistance
measurements of some coils from one schematic to the other, it may just me
differences in their test equipment, or component tolerances.....




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