Quote:
Originally Posted by ostlar
Thanks for the replies. On my other working TV with the exact same chassis, I get 20 kilo ohms on the 115V line on the secondary side, but on the non working TV I get 25 ohms.
This is definitely something shorting out, but I am not sure what. I've come to a dead end in around the HOT.
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Here is a possibility - Each color tv has a Degaussing circuit, it sends full power
to a coil for the first second the tv is switched on, then a thermister gets hot,
and it gets turned off gently. It's possible your "good tv" has had this circuit
fail, and it reads open, while the other tv has a good Degaussing circuit
and you read 25 ohms... Most often this is on a plug, you could try
unplugging it and retest. The coil is around the picture tube.
On the schematic it's near the AC plug at the bottom....
Second possibility - you have a problem with a circuit fault, nearly a short
and it should be smoking or kicking a fuse..... 25 Ohms should be easy
to find.... Are the probes in exactly the same spots including polarity
when you measure this on both tvs?
If it's not the degaussing circuit then you can unsolder components, and
disconnect parts of the circuit and recheck resistance to find the 25
ohm section.....
Also - check the other resistors next to the ones getting hot, R 701, - R707,
They makeup a resistor network with a test point 18 I think it says...
Pretty much anything around IC701.....
Since you have a good tv as a reference, you may want to check resistances
at critical points, and even voltages, like at IC 701, resistances at the
flyback, Horiz. Output Transistor etc.... Keep in mind when checking
resistance probe polarity is important, if the meter 'sees' a diode
it will give a different reading in one direction, so remember
to keep polarity the same when measuring from one tv
to the other.....
Also in one of those Hold Down Protection Circuit videos the
guy finds a bad cap with a bulge on top, so keep your
eyes open for stuff that don't look right....
.