E390vl help with regulator testing

[tom66]

Re: E390vl help with regulator testing

I think the best you can do is replace the regulator & nearby caps and see if it is OK. If not, the CPU might be bad.

[audiofreak19]

Re: E390vl help with regulator testing

Do you think the CPU would be causing the shutdown after turning on.

[tom66]

Re: E390vl help with regulator testing

Low voltage could cause it to crash, if that's what you're asking.

[audiofreak19]

Re: E390vl help with regulator testing

So I replaced the flash chip again with the same new one I bought and it does the same thing no vizio logo on or anything. I checked the regulator I said was getting hot and it's getting hot. I rushed and grabbed my multimeter cause I didn't want it getting hot for long and these are the readings. On the input it's getting 3.28v which is good. The output is getting .967 and slowly growing. And the adj is at 0. I think this regulator is bad. Nothing else on the board gets hot but this reg.

[audiofreak19]

Re: E390vl help with regulator testing

Can anyone help me find the regulator H1117C 1.2 207. I'm trying to find it to buy but can't figure it out.

[stj]

Re: E390vl help with regulator testing

http://www.logictoyz.com/electronic-...1117-1-2v.html

1.2v is pretty low for a 1117 - you may get lucky with the big guys like digikey though.

[Caleb]

Re: E390vl help with regulator testing

I think this will work for you, you just need to verify if you need an adjustable regulator or a standard regulator

[stj]

Re: E390vl help with regulator testing

http://www.digikey.com/product-searc...=0&pageSize=25

[audiofreak19]

Re: E390vl help with regulator testing

I know its a adj reg. How do I know which one from digikey to pick.

[Caleb]

Re: E390vl help with regulator testing

You just need to get the main points and you should be fine
-1117 regulator
-adjustable
-1.2v low dropout
-correct package size
the one I linked in my previous post should do the trick

[budm]

Re: E390vl help with regulator testing

Do you need adjustable regulator or 1.2V fixed regulator? It seems to me you have 1.2V fixed, not adjustable.
The adjustable regulator will have resistors network to set the output voltage above the 1.25V Vref. The fixed regulator will have pin 1 (gnd) connected to ground. Are there any resistors connected to pin1? The regulator can run hot if it is oscillating due to bad in put or output filter caps, or due to very heavy load.

[audiofreak19]

Re: E390vl help with regulator testing

Only reason I thought it was adjustable was because pin 1 was labeled adj on the pcb

[audiofreak19]

Re: E390vl help with regulator testing

And I would have to check the filter caps with a ear meter right.

[audiofreak19]

Re: E390vl help with regulator testing

Sorry esr meter

[budm]

Re: E390vl help with regulator testing

Lets try the easy thing first, measure the resistance of the output pin with ref to ground to see if the regulator is trying to feed really low resistance load which will cause to much current draw, that will be the easy test first.

[ecking767]

Re: E390vl help with regulator testing

tracing the tab of the regulator it look like it going to inductor,resistor and then main CPU,did you check the processor for overheating?

[audiofreak19]

Re: E390vl help with regulator testing

Nothing else on the board over heats. I touched just about every other component to see if anything else was getting hot and they weren't.

[audiofreak19]

Re: E390vl help with regulator testing

Hey sorry to get to ya after a couple of days. I measured the resistance of the output to a ref ground on the chassis and it read 1.1ohms.

[audiofreak19]

Re: E390vl help with regulator testing

The resistance between the adj and the input is 58 ohms. Between tab and adj it's 1.1 ohms. Between the tab and the input it's 58 ohms. All of these measurements were taken with the tv unplugged.

[budm]

Re: E390vl help with regulator testing

Hey sorry to get to ya after a couple of days. I measured the resistance of the output to a ref ground on the chassis and it read 1.1ohms.

I think you should remove that regulator and then measure the resistance between the output pad (center pin or big tab) and circuit ground (chassis) to see if it still show 1.1 Ohm.
Also post the good closed up picture after the IC is removed.