Maker Pro
Maker Pro

HV probes, & flyback measuring.

D

Dani

Jan 1, 1970
0
What do you guys use for HV Probes? A stand alone unit, or a DMM ad on
unit? Also, I'm looking at getting a Circuit-Test LCR meter Model #
DLM-240, or something equivilent.Ranges are: Capacitance to 2000uF,
Inductance to 200 H, Resistance to 20M Ohm

Is this good enough to measure bad flyback windings? What do you guys
use? Thanks, Dani.
 
W

Wild Bill

Jan 1, 1970
0
There are lots of good HV probe styles available. I kinda like a probe with
a built-in analog meter, just because it is simple to use, and doesn't
require a separate meter, although I have and use the types that plug into a
DMM too.

See the FAQ section about flyback/IHVT testing. One important test is an
inductor ringer, which can check for shorted turns.
There are several tests/checks to be done to analyze the quality of
flybacks. Some Sencore testers have a variable horizontal drive signal that
can be used to drive the primary of the transformer (out-of-circuit), for a
relative output test.
http://www.repairfaq.org/REPAIR/

Cheers
WB
.............
 
J

Jerry G.

Jan 1, 1970
0
In our shop we prefer using a stand alone instrument for measuring the
CRT high voltage.

We are now finding that investing in to anything to do with servicing
CRT equipment is becoming more limited and less feasable as time goes
on. The cost of the flat panel TV sets and monitors are dropping
every month. At the same time, manufactures are not interested in
having the burden of having parts distributions for the CRT models.

As for the LCD and plasma devices, these are mostly serviced at the
modular level. For servicing, they usualy require dedicated tools and
service information.
 
J

James Sweet

Jan 1, 1970
0
Dani said:
What do you guys use for HV Probes? A stand alone unit, or a DMM ad on
unit? Also, I'm looking at getting a Circuit-Test LCR meter Model #
DLM-240, or something equivilent.Ranges are: Capacitance to 2000uF,
Inductance to 200 H, Resistance to 20M Ohm

Is this good enough to measure bad flyback windings? What do you guys
use? Thanks, Dani.


I use a Fluke HV probe that plugs into my multimeter. I think it's rated
100KV.
 
J

James Sweet

Jan 1, 1970
0
Jim said:
More likely 50KV.


Just checked and it's 40KV, at any rate it goes higher than I've ever
had to measure.
 
J

Jim Yanik

Jan 1, 1970
0
Just checked and it's 40KV, at any rate it goes higher than I've ever
had to measure.

let's hope you don't encounter any CRT anodes at 40KV.....unless you're
wearing your lead undershorts! ;-)
 
J

James Sweet

Jan 1, 1970
0
Jim said:
let's hope you don't encounter any CRT anodes at 40KV.....unless you're
wearing your lead undershorts! ;-)


From the look of the thing I suspect it could safely go much higher.
Not to say one should routinely abuse something, but Fluke is well known
for using conservative ratings with lots of safety margin.
 
J

Jim Yanik

Jan 1, 1970
0
From the look of the thing I suspect it could safely go much higher.
Not to say one should routinely abuse something, but Fluke is well known
for using conservative ratings with lots of safety margin.

I was thinking of X-ray generation at voltages above ~25KV,not the safety
of the probe.
 
J

James Sweet

Jan 1, 1970
0
Jim said:
I was thinking of X-ray generation at voltages above ~25KV,not the safety
of the probe.


I've come across TVs and monitors with 35KV anodes, mostly projection or
very high resolution.

I saw on a website once they were trying to generate xrays with a CRT,
even up as high as 60KV or so there was not a measurable amount due to
the leaded glass. A few rectifier tubes though did generate enough xrays
to take a few pictures.
 
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