Vizio SV420M, Power light stuck on. No standby or picture

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

I retested the voltage with the cable attached. I'm getting the 12V now. Sorry for the confusion. So power board seems ok?

Do you think there's a remote chance of getting this working by replacing the EEPROM? I do know how to solder and have the necessary tools for it. Of course I wouldn't hold it against you if it didn't fix the issue.

[budm]

Re: Vizio SV420M, Power light stuck on. No standby or picture

OK, good. EEPROM, may be or may be not but since SJ sells EEPROM chips, then it is more likely to have EEPROM problem. You can E-MAIL SJ and ask questions, they are pretty good on giving info.

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

Ok. Provided I get the OK from my friend (whom the TV belongs to), I will go that route and I'll report back here with my findings.

Thank you guys so much.

[keeney123]

Re: Vizio SV420M, Power light stuck on. No standby or picture

If there is a power up relay I would verify that it is being told to stay on otherwise the contacts have fused shut and that will cause all sorts of problems with the protection circuit in these devices. It has over voltage and over current protection and depends on a soft start up to work properly.

[Amraks]

Re: Vizio SV420M, Power light stuck on. No standby or picture

check screen with flash light just to see if anything is being displayed on screen.

If you get Scan displayed on screen, it would be epprom.

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

The relay thing sounds like it is a little bit above my understanding of electronics.

As far as the flashlight thing, I tried seeing if I could see a picture with one a couple days ago but I didn't see anything. I'll look again more thoroughly tonight and make sure.

[budm]

Re: Vizio SV420M, Power light stuck on. No standby or picture

There is no relay on this power supply-inverter board combo.
http://www.shopjimmy.com/media/catal...2-0780-top.jpg

[keeney123]

Re: Vizio SV420M, Power light stuck on. No standby or picture

I am talking about a power on AC relay. What I have noticed on some devices they have a feedback circuit that keeps the relay on or it turns off when either the power button is pushed or there is a problem with the current of voltage on any of the boards. If this TV does has a relay like that, then if the contacts fuse together the start up of the power supply would be to quick and there would be to much of a surge of current. The software would detect this and depending on who wrote the software it can turn of the whole thing of part of the circuit.

[budm]

Re: Vizio SV420M, Power light stuck on. No standby or picture

No AC power relay used in this TV so the OP does not have to look for them.

[keeney123]

Re: Vizio SV420M, Power light stuck on. No standby or picture

OK just did not know, I know they are used on some models. Have only done some CRT repair and a couple of LCD, but do understand software has a lot of control, maybe to much control on these newer TVs.

[keeney123]

Re: Vizio SV420M, Power light stuck on. No standby or picture

Still the power on button should work to shut the unit down. If it is not doing that than there is something wrong at that point.

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

Hey guys. Just wanted to follow up on this. I replaced the U14 EEPROM but I still have the same issue.

Any other ideas on the possible cause or should I give up and try to find a main board?

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

Bump. Anyone?

[keeney123]

Re: Vizio SV420M, Power light stuck on. No standby or picture

I am not an expert on these things, but do you have aside panel or button panel that controls the input, menu etc? If so I would try and dis connect it from the main board and then plug the TV in and see if it still powers up by itself.

[SmartSped]

Re: Vizio SV420M, Power light stuck on. No standby or picture

Maybe a stuck button or something? I'll see if maybe I can disconnect the buttons and see if maybe that changes something.