M
Marc
- Jan 1, 1970
- 0
I recently acquired a non-working Sony KV-2780R television
manufactured in 1987.
I know nothing of the history of this television, but it was one step
away from the dump...and is an excellent candidate for educational
purposes...(aka FREE!)
I pulled the back off, and checked the main fuse, it was ok.
I plugged it in, and turned it on. I could hear the "on" circuit come
on, but no sound or picture.
I then unplugged it and began taking a closer look at the video
circuitry.
(the audio portion of the circuitry appears to be contained on a
separate board,
probably modular, and probably used on several different models of
televisions)
The only "clean" area on the video circuit board was a
heatsink/transistor sub-assembly located just in front of the flyback
transformer.
The heatsink/transistor sub-assembly was just sitting there, loose,
de-soldered from the board. (all three of the transistor leads, as
well as the heatsink mountings were de-soldered from the board)
The transistor (D1497) is shorted out.
My guess is this: that a repair technician checked the set, and
determined that, at the very least, the HOT was bad, and the overall
cost of the repair was too expensive, so the television was not
repaired.
Here is my question:
When the HOT is determined to be shorted, is this symptomatic of a
larger problem???
Possibly other parts down stream or up stream (so to speak) shorting?
Again, any and all help is appreciated,
Thanks,
Mark
manufactured in 1987.
I know nothing of the history of this television, but it was one step
away from the dump...and is an excellent candidate for educational
purposes...(aka FREE!)
I pulled the back off, and checked the main fuse, it was ok.
I plugged it in, and turned it on. I could hear the "on" circuit come
on, but no sound or picture.
I then unplugged it and began taking a closer look at the video
circuitry.
(the audio portion of the circuitry appears to be contained on a
separate board,
probably modular, and probably used on several different models of
televisions)
The only "clean" area on the video circuit board was a
heatsink/transistor sub-assembly located just in front of the flyback
transformer.
The heatsink/transistor sub-assembly was just sitting there, loose,
de-soldered from the board. (all three of the transistor leads, as
well as the heatsink mountings were de-soldered from the board)
The transistor (D1497) is shorted out.
My guess is this: that a repair technician checked the set, and
determined that, at the very least, the HOT was bad, and the overall
cost of the repair was too expensive, so the television was not
repaired.
Here is my question:
When the HOT is determined to be shorted, is this symptomatic of a
larger problem???
Possibly other parts down stream or up stream (so to speak) shorting?
Again, any and all help is appreciated,
Thanks,
Mark