Vizio M65 C-1 power supply dead - NO standby voltage

[funkmunk3y]

Hello!
I was given this Vizio because it would freeze up after a few minutes of operation. There were no obvious burns marks or failures. When I was checking the power supply - I slipped & shorted it (tiny crackle & spark) at one of the 12 volt pins - now the entire board is dead & has NO standby voltage @ the connector to the main board.

The fuse at the power input is reading good - the main caps are reading in the 160's & all the diodes read good except one (D9103 - pictured) - but it only reads bad in circuit - I pulled it & it tests o.k.

There doesn't seem to be getting power to the cold side of the board anymore...

Any help, direction or what/where to test would be greatly appreciated - Mike

[IMG][/IMG]

[dick_barton]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Check R9201 (0.1 ohm) resistor.

Power supply within this pdf
https://www.electronica-pt.com/esque...6.1e-la-69941/

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Reading 0.4

[dick_barton]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

That would appear to be OK.
So you have no secondary voltages at all; no standby voltage?

R9841 looks like one of the legs is not soldered in. It could be just the photo?

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

No standby - no 12v, no 24v - nothing seems to be making it to the cold side.

GREAT eye though - R9841 was missing solder on 1/2 of the pin.

[dick_barton]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

What voltage do you have across C9141 (VCC) and also across R9102 (BNO) at switch on.

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

R9012 = .51 dcv

c9141 = 0.0 dcv

[R_J]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Check R9113, if ok, then check the values of R9137, R9138 & R9139

[dick_barton]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

If there is no voltage across C9141 then there is no supply to run the IC9101 and therefore to switch mosfet Q9101 to power transformer T9101 to provide the secondary voltages.

My error - the resistor to check the voltage across was R9102 not R9012

Can you check the voltage across C9109 and C9103 at standby and switch on.

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

If there is no voltage across C9141 then there is no supply to run the IC9101 and therefore to switch mosfet Q9101 to power transformer T9101 to provide the secondary voltages.

My error - the resistor to check the voltage across was R9102 not R9012

Can you check the voltage across C9109 and C9103 at standby and switch on.

No - my bad - it was the 9102 - i mis-typed it as 9012...

[R_J]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Are you using hot ground to check these voltages in the primary? If you are using the schematic, there are two sets of series resistors coming from point N, check the voltage at point N and then after each resistor in the series. Point V is the startup vcc supply point

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

If there is no voltage across C9141 then there is no supply to run the IC9101 and therefore to switch mosfet Q9101 to power transformer T9101 to provide the secondary voltages.

My error - the resistor to check the voltage across was R9102 not R9012

Can you check the voltage across C9109 and C9103 at standby and switch on.

Again, my bad - the 9141 is reading 00.4 when testing dcv in the 200m setting of my multimeter.

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

R9113 = 00.3

r9137 = 14.9
r9138 = 14.9
r9139 = 18.2

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Plugged in:

C9103 = 4.5 dcv

C9109 = .7 dcv

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Unplugged:

C9103 = 0.0

C9101 = 0.0

The longer I held it there the lower it went... same for plugged in but climbing up.

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Are you using hot ground to check these voltages in the primary? If you are using the schematic, there are two sets of series resistors coming from point N, check the voltage at point N and then after each resistor in the series. Point V is the startup vcc supply point

I am not using the schematic - I cannot read one - I am an amateur at best.

[R_J]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

R9113 = 00.3

r9137 = 14.9
r9138 = 14.9
r9139 = 18.2

One end of R9139 should connect to one end of R9113, is R9113 ok? it should be 5R1Ω

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

R9113 reads 3.5Ohms

[R_J]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

R9139 = 18.2

Is this Dc voltage? what are you using for ground?
Check the resistance between J934 (this is one end of R9139) and C9109 + and then to R9113

[funkmunk3y]

Re: Vizio M65 C-1 power supply dead - NO standby voltage

Is this Dc voltage? what are you using for ground?

Yes, DCV - I was measuring across from solder joint to solder joint