Help (TV horizontal transitor keeps damaging)
 

I have a TV which the horrizontal transistor keeps damaging.
I would like to know what caused the transistor S2000A3 short on the
collector to emiter? I've replaced the transistor 3 times. Whenever after
I've replaced the transistors, the TV will work for 5 to 10 seconds then it
stops. The last time I tried, I replace using a S2000N, the 100 ohm resistor
at the base of the transistor burnt. Is the base voltage too high?

The following link is the schematic diagram of the TV. The transistor is
highlighted in yellow.
http://sg.geocities.com./colorprint88/tv.jpg

Please advice how to solve the problem
Thankyou

Regards,
Richard

What is causing the transistor to self destruct? No Drive, Excessive
current, blown LOPT, bad yoke, problems in deflection return circuits,
pin-cushion circuits, power supply regulation ETC. Make and model numbers
first then any real diagnostics you have actually done other than throw
transistors at the thing. Base resistor being overheated indicates excessive
current through the transistor before self destructing.
"Richard" wrote in message
...
I have a TV which the horrizontal transistor keeps damaging.
I would like to know what caused the transistor S2000A3 short on the
collector to emiter? I've replaced the transistor 3 times. Whenever after
I've replaced the transistors, the TV will work for 5 to 10 seconds then
it
stops. The last time I tried, I replace using a S2000N, the 100 ohm
resistor
at the base of the transistor burnt. Is the base voltage too high?

The following link is the schematic diagram of the TV. The transistor is
highlighted in yellow.
http://sg.geocities.com./colorprint88/tv.jpg

Please advice how to solve the problem
Thankyou

Regards,
Richard

Looks like a TX826 RCA/GE 14" chassis!
Change CP08 100uf @ 35 volt capacitor.
The flyback is likely bad also, but if the cap
is very bad, that should fix it! Rono.

"Richard" wrote in message
...
I have a TV which the horrizontal transistor keeps damaging.
I would like to know what caused the transistor S2000A3 short on the
collector to emiter? I've replaced the transistor 3 times. Whenever after
I've replaced the transistors, the TV will work for 5 to 10 seconds then
it
stops. The last time I tried, I replace using a S2000N, the 100 ohm
resistor
at the base of the transistor burnt. Is the base voltage too high?

The following link is the schematic diagram of the TV. The transistor is
highlighted in yellow.
http://sg.geocities.com./colorprint88/tv.jpg

Please advice how to solve the problem
Thankyou

Regards,
Richard

It's an extremely tough set to fix many times. An open capacitor CP08
or bad connections from glue securing coil LP02 to the board can cause
the transistor to fail. Other possibilitys include a bad HV
transformer, shorted diode near the HV transformer, picture tube with
no vaccuum, bad solder connections anywhere in the HV area ect. Not
many easy fixes for output shorting in the TX series sets.

You missed at least one bad capacitor in the circuit. That looks like
the old tx81 chassis that commonly had the 100uf capacitor go bad in
the base drive, will blow the HOT every time.

off an a tangent,,,,,,,,,,

Why the hell do they need a 100uF in a circuit that drives at 15.734
Khz ?

This is ridiculous, a 10 uF would be fine. THEY MUST WANT IT TO FAIL.

JURB

(yes I know about low impedance, that's why I said 10 uF and not 1 uF)

Thanks guys, the capacitor did really solved the problem. :)
This is a TX80(14") chassis of a toshiba TV
Why is this capacitor so important that it causes damage the transistor?

Richard