vizio vp50

[heavymachines]

Re: vizio vp50

That is not right; is battery definitely the right way around?

have positive (white) wire to resistor and (blue) wire to middle pin

[heavymachines]

Re: vizio vp50

is it possible that it's bad and acting as a pass thru thus creating a 16 volt reading on the power board thus meaning it's having a 16 volt input to the tl431? on the power board????????? kinda what it doing on this breadboard setup....with the 7.64 volt input...and it outputting same voltage..



i do have tl431 on a different power board i can desolder and retest should i commence?

[tom66]

Re: vizio vp50

I suspect the part is faulty; this is causing your low voltage readings.

[tom66]

Re: vizio vp50

Please try with the other TL431 so we can check the testing method is right.

[heavymachines]

Re: vizio vp50

here is a pic doing the test so you can observe

[tom66]

Re: vizio vp50

Ah I realise I may be in error here. Just realised...
Try moving the ref connection from 1-2 to 1-3.

[heavymachines]

Re: vizio vp50

i think so because i just tested two more both from different junk power supplies and same result...

[tom66]

Re: vizio vp50

Remove the 1-2 jumper and move it to 1-3.

[heavymachines]

Re: vizio vp50

Remove the 1-2 jumper and move it to 1-3.

okay with all three tl431 i get

pin 1-3 0.00volts


negative probe to pin 1 and positive probe to resistor i get 4.97 volts with 7.64 battery input voltage...

[tom66]

Re: vizio vp50

You want to do positive probe to resistor, negative probe to ground/battery negative.

[heavymachines]

Re: vizio vp50

You want to do positive probe to resistor, negative probe to ground/battery negative.

i did in above post

[tom66]

Re: vizio vp50

I don't understand the 4.97V. Do you have other resistor values?

[heavymachines]

Re: vizio vp50

I don't understand the 4.97V. Do you have other resistor values?

some bunch in junk boards what would you like me to use? pick random or specific 1 k i am using 1 k right now...

[tom66]

Re: vizio vp50

Random from 470 ohm to 2.2k ohm.

[heavymachines]

Re: vizio vp50

okay found resister brown-black-brown-gold-yellow measures 100ohms on dmm and voltage results are 6.74v input and 4.21v measurement at neg probe pin 1 and positive at resistor end

[tom66]

Re: vizio vp50

Either it's wired up wrong or the device isn't working, can you compare to the other devices, also what is the part # on it?

[heavymachines]

Re: vizio vp50

Either it's wired up wrong or the device isn't working, can you compare to the other devices, also what is the part # on it?

ic #1
utc
TL431
RMF


ic#2
KA
431AZ

ic#3
HA
431
405c

all shunt style

all get same now around 4.10 volts

[tom66]

Re: vizio vp50

I'm suspicious of your meter battery. Can you make sure it's OK?

[heavymachines]

Re: vizio vp50

I'm suspicious of your meter battery. Can you make sure it's OK?

sure thing will go next door and get new one just for good measure brb

[heavymachines]

Re: vizio vp50

okay got 2 new batteries measure 9.3 volts each now that same voltage is input for bread board now reads 6.65 volts