Hi;
This is a Vizio M420NV. Backlight was out, I found an open 3A fuse (TF1) on the main board that carries
12.4 vdc. When fuse replaced, the backlight will flash a couple of times and poof goes the fuse again.I don't have a diagram. I wonder if this might be due to a inverter fault ? I checked power transistors on main and power supply board. Any ideas ?
Thanks,
carries 12.4 vdc. When fuse replaced, the backlight will flash a couple of times and poof goes the fuse again.
?Can you hear any fizzing/arcing across turns in the inverter Tx ? Can you reduce the mains voltage a bit and maybe increase the amount of on-time a bit , to monitor the fault situation a bit longer.
carries 12.4 vdc. When fuse replaced, the backlight will flash a couple of times and poof goes the fuse again.
t ?
The fuse for the 12V feed to the main does not cover the inverter B+, that' s fed directly from the smps to the inverter board(s) and fused at that end . The inverter was blinking because the main is gimpy..
If the 12V fuse on the main is opening, you most likely have a shorted regu lator IC on the main, and possibly an IC after that drawing and overheating the regulator. Unfortunately, Vizio is loathe to provide any service info rmation on their boards. You're best bet at this point is to replace the m ain. Make sure you get the correct one as there are typically several vers ions for the same model to match the display\tcon.
t carries 12.4 vdc. When fuse replaced, the backlight will flash a couple o f times and poof goes the fuse again.
ult ?
t's fed directly from the smps to the inverter board(s) and fused at that e nd. The inverter was blinking because the main is gimpy..
gulator IC on the main, and possibly an IC after that drawing and overheati ng the regulator. Unfortunately, Vizio is loathe to provide any service in formation on their boards. You're best bet at this point is to replace the main. Make sure you get the correct one as there are typically several ve rsions for the same model to match the display\tcon.
Tomorrow I will try to dial down the power a bit and see if the invert xformers fizzle with a new fuse...
Thanks
carries 12.4 vdc. When fuse replaced, the backlight will flash a couple of times and poof goes the fuse again.
Hi there, I would also check any electrolytic capacitors on the inverter board, making sure they are at least 105 degree celcius type with low equivalent series resistance - low ESR type.
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