Hi,

Sanyo 19" TV model DS19204, ch 19204-01 mfg 11/04

I have this TV in my shop with loss of vertical deflection (TV goes off
shortly after turn on). I have no SM or pin out information (searched web)
about IC501, LA78040N. B+ (24V) is present at pin 2 when TV is turned on.
Pin 4 is ground. I saw an abnormal signal on pins 3, 5, and 6 which causes
a small deflection as a light shading above and below the center horizontal
line (TV is on long enough for this to appear). I tested components around
IC501 and found no defective part. I suspect that the source of the vertical
signal (which is abnormal) that drives IC501might be the problem?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.

Brad:
It sounds to me that you should replace the LA7804 chip. Also check
the surrounding circuitry for leaky or high esr electrolytics (you must
check them with an ESR meter... or just replace all of them... maybe a
half dozen or so) and check for shorted or open diodes, open resistors
and faulty solder connections near the chip.
electricitym
- - - - -


Brad wrote:
Hi,

Sanyo 19" TV model DS19204, ch 19204-01 mfg 11/04

I have this TV in my shop with loss of vertical deflection (TV goes off
shortly after turn on). I have no SM or pin out information (searched web)
about IC501, LA78040N. B+ (24V) is present at pin 2 when TV is turned on.
Pin 4 is ground. I saw an abnormal signal on pins 3, 5, and 6 which causes
a small deflection as a light shading above and below the center horizontal
line (TV is on long enough for this to appear). I tested components around
IC501 and found no defective part. I suspect that the source of the vertical
signal (which is abnormal) that drives IC501might be the problem?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active key logger (spyware) in your PC.