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Blown Resistor in a Citizen 25" TV

C

Craig McLean

Jan 1, 1970
0
Hello.

A friend of mine found out I sort of know how to repair televisions so I'm
fixing his. It has a blown resistor in the power supply section of the
circuit board. The TV is a Citizen 25", model number JCTV3413A. There is
also a number on the printed circuit board TMX456A. The tube was made by
Orion and is model number A63AHC26X. The TV was purchased and is used in
Alberta Canada. The blown resistor is in the Power section of the circuit
board and is R515. I can't identify the resistor as the colour code was
burned away and I haven't been able to source a schematic diagram. Can
anybody help me with identifying this part? It is probably between 1 and 5
watts. It may be 1.5 ohms. Also any theories on why the resistor may have
cooked? I didn't want to start troubleshooting until I was sure I could get
a replacement resistor, so I haven't looked yet. However if you have some
clues you could offer I would appreciate that.

One other thing I noticed. There is a large 20 watt resistor that actually
sits more or less overtop of the resistor which burned it's value is 180
ohms. I noticed it's ceramic casing has a crack in it. I tested it and it
still has the proper value (or at least it does when it is cold). I'm going
to replace it as well because they are cheap. Might this have something to
do with R515 burning. The PCB is ambiguous but it might be R506.

Thank you for any help you may be able to offer.
 
J

James Sweet

Jan 1, 1970
0
Craig McLean said:
Hello.

A friend of mine found out I sort of know how to repair televisions so I'm
fixing his. It has a blown resistor in the power supply section of the
circuit board. The TV is a Citizen 25", model number JCTV3413A. There is
also a number on the printed circuit board TMX456A. The tube was made by
Orion and is model number A63AHC26X. The TV was purchased and is used in
Alberta Canada. The blown resistor is in the Power section of the circuit
board and is R515. I can't identify the resistor as the colour code was
burned away and I haven't been able to source a schematic diagram. Can
anybody help me with identifying this part? It is probably between 1 and 5
watts. It may be 1.5 ohms. Also any theories on why the resistor may have
cooked? I didn't want to start troubleshooting until I was sure I could get
a replacement resistor, so I haven't looked yet. However if you have some
clues you could offer I would appreciate that.


Something is shorted, probably a diode or transistor, maybe a number of
things. It shouldn't be hard to track down what it is. If you can figure out
where the resistor figures into the circuit it's quite possible to guess an
appropriate value for it.
 
A

AshTray700

Jan 1, 1970
0
the voltage regulator is probably out and thats why that resistor is
burned, if you change it, you will just roast another one. look for the
nearest chip attached to a heat sink , flip the pcb and look at the
traceings, are they browned? check the diodes nearby also, voltage
regulator chip (trnasistor type = around $5 or so, ic type up to like $30)
from my experience just about all tv sets with power supply failures like
that (burned components, or no power) are due to a bad vr chip, it
produces a lot of heat and wears out due to it, if you change it make sure
that you attach it back to the heat sink with the heat transfer grease or
patch in place if it has one. you will need to replace the resistor as
well and any other component damaged due to excessive current
 
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