Re: Panasonic TNPA5081 rebuilt, poor image
True--Your scope is showing 400 odd V --P-P.
Meaning that you're showing a signal going Minus 200 odd volts to 200V Positive--ish.
As Tom says, the signal is swinging around the 0V point, both positive peaks and negative troughs....
Therefore, the '0' Volts point on the screen is approx halfway down,--the middle, (actually by the look, 1 large graticule division below middle, giving your sub-fields about 50V amplitude, and not enough........
Give you an idea--Where on the Scope-screen is the trace when you remove the signal from the scope....? I'll bet is approx halfway down screen, (actually 1 div below centre-line--ish.)
The voltages across the panel, from the SS side to the SD side are AC voltages--in opposition, one side Minus, other Positive then it reverses, but these AC voltages are derived from DC sources--hence the need for all the switching transistors. The voltages HAVE to be AC as they are insulated from the gas inside the panel by the dielectric layer, applying DC will give no gas ionisation or light production.
Originally posted by keats11
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Meaning that you're showing a signal going Minus 200 odd volts to 200V Positive--ish.
As Tom says, the signal is swinging around the 0V point, both positive peaks and negative troughs....
Therefore, the '0' Volts point on the screen is approx halfway down,--the middle, (actually by the look, 1 large graticule division below middle, giving your sub-fields about 50V amplitude, and not enough........
Give you an idea--Where on the Scope-screen is the trace when you remove the signal from the scope....? I'll bet is approx halfway down screen, (actually 1 div below centre-line--ish.)
The voltages across the panel, from the SS side to the SD side are AC voltages--in opposition, one side Minus, other Positive then it reverses, but these AC voltages are derived from DC sources--hence the need for all the switching transistors. The voltages HAVE to be AC as they are insulated from the gas inside the panel by the dielectric layer, applying DC will give no gas ionisation or light production.
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