Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Fannie
 
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Default TV startup problem (new thread)

Quick recap:
27" MTC (MTV-2800s) television
replaced blown fuse
transformer in power supply squeals
no sound, no picture, no pic tube filament lighting

checked/replaced caps, incircuit checked diodes
checked switching circuitry transistors

Front LED (red) lights up.

I'm pretty well convinced the power supply is able to
function. The fuse that blew seems to be for the B+

Question:
D1398 (horizontal output transistor with damper diode) -
I've taken it out of the TV and I've no silly scope. I'm not
convinced it's in good working order and I wonder if it could
be the culprit. Is there a way to test this thing with a meter now
that I've got it pulled out of the TV? And could it cause the
symptoms I've listed above?


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Art
 
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Default TV startup problem (new thread)

Simple resistance test or diode test will tell you it the transistor is
shorted or not.
"Fannie" wrote in message
...
Quick recap:
27" MTC (MTV-2800s) television
replaced blown fuse
transformer in power supply squeals
no sound, no picture, no pic tube filament lighting

checked/replaced caps, incircuit checked diodes
checked switching circuitry transistors

Front LED (red) lights up.

I'm pretty well convinced the power supply is able to
function. The fuse that blew seems to be for the B+

Question:
D1398 (horizontal output transistor with damper diode) -
I've taken it out of the TV and I've no silly scope. I'm not
convinced it's in good working order and I wonder if it could
be the culprit. Is there a way to test this thing with a meter now
that I've got it pulled out of the TV? And could it cause the
symptoms I've listed above?




  #3   Report Post  
Fannie
 
Posts: n/a
Default TV startup problem (new thread)

With a normal transistor I'm confident in the meter
readings, but with that damper diode and interpreting
the meter readings I'm no so confident.

..... something about reading a reading of less than
50ohms across any pair of legs may indicate a busted
HOT [??]

I'm wondering if that's reliably true or not.

"Art" wrote in message
...
Simple resistance test or diode test will tell you it the transistor is
shorted or not.
"Fannie" wrote in message
...
Quick recap:
27" MTC (MTV-2800s) television
replaced blown fuse
transformer in power supply squeals
no sound, no picture, no pic tube filament lighting

checked/replaced caps, incircuit checked diodes
checked switching circuitry transistors

Front LED (red) lights up.

I'm pretty well convinced the power supply is able to
function. The fuse that blew seems to be for the B+

Question:
D1398 (horizontal output transistor with damper diode) -
I've taken it out of the TV and I've no silly scope. I'm not
convinced it's in good working order and I wonder if it could
be the culprit. Is there a way to test this thing with a meter now
that I've got it pulled out of the TV? And could it cause the
symptoms I've listed above?






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