5v present on stb voltage but no 12v & 24v & 5v of system on power supply MLT 070a PLS HELP

If you measures at the power supply module and the voltages are DC then you probably have some bad regulators. Parts are usually not coded so replace the power supply module.

nope

1. When the TV powered up, please measure the 24V, 12V & 5V are there, if one voltage is missing, you may have a defective power supply.

2. If the power supply lost the 24V source, you may unplug the power supply connector on both the inverter board, then power it up, if you got the 24V back, you do have a defective inverter board, you may unplug them one at a time to locate the bad one.

3. If the power supply & inverters are good, you may have a defective main board. The common problem on the main board is that a voltage regulator is bad, you may use your millimeter to measure them 1 x 1. The out put voltage (on the heat sync) should be 1.25V + the control voltage (Pin 1), for example: if the control pin voltage is 0, the output voltage should be 1.25V, if the control voltage is 2.05V, the output voltage should be 3.3V, if one of them is out of range, replace it, you may find the part from Digikey Co. The part number printed on the regulator is AMC1117.


Good luck!

I'm a little confused here as without the 5 volt standby voltage the blue light won't come on, the TV will be dead like its not plugged in, are you sure you were on the right pin when you measured that? It almost sounds like your on the PSON or PWR-ON pin.

Did you check for the "ON" or "PS ON" signal on the power supply board? It should be around 3.3vdc.This signal comes from the main board, it commands the other sections of the power supply to come on and turn on the TV set. This signal should be present when you press the power button from either the TV or remote. If you are not getting this signal from the main board, you're most likely dealing with a main board failure. If you are dealing with a main board failure, take heed, some Vizio main boards can be expensive.

you need to check weather the power supply has complete output dc voltages 5v stand by, 5v detect 12v-16v for audio and tuner and 24v for back light. if just only an stand by voltage, the cause is either the power supply failed or the main board detect an error in the inverter board .

check your power supply use a voltage tester make sure your power supply has a 5v,12v,24v output.If no voltage is present replace the power supply.

hi... hope this can help....it's the most common for any power supply...RED is for +5V DC, BLACK is for Ground, yellow is for +12V DC...GREEN is for earth ground...in cases for a 12V output adaptor redi is the 12V and black for ground..pls. don't forget to rate and vote ...thanks......

Your power supply on the dc output should have the floowing DC voltages, 5v, 12v, and 24v. Just start probing the connectors of the power supply. 24v is needed for the backlights inverter board, 12v for sounds, 5v for logic board.

hi remove the supply to the main board & inverter, now power your psu if give you this same above voltages , go for new power supply unit. change your power