Element elefw605 power issue maybe?

[budm]

Re: Element elefw605 power issue maybe?

Canned air duster is only $3 ~ 4.

[R_J]

Re: Element elefw605 power issue maybe?

It could also be that if that 5 volt standby being only 3 volts, when you first plug in the tv, the eeprom and microprocessor only see 3 volts instead of 5 could cause it to be confused.
This low voltage could be a bad secondary cap or one of the small startup caps in the primary

[Demonata08]

Re: Element elefw605 power issue maybe?

Canned air duster is only $3 ~ 4.

I might be missing something there. How would it get it cold? I use an electric air duster myself.

Unless it comes out cold in the can.

[Demonata08]

Re: Element elefw605 power issue maybe?

It could also be that if that 5 volt standby being only 3 volts, when you first plug in the tv, the eeprom and microprocessor only see 3 volts instead of 5 could cause it to be confused.
This low voltage could be a bad secondary cap or one of the small startup caps in the primary

That would be very wishful thinking on my part. I wonder if i could give it 5v from a 5v pin and see what happens

[budm]

Re: Element elefw605 power issue maybe?

I might be missing something there. How would it get it cold? I use an electric air duster myself.

Unless it comes out cold in the can.

Turn the can upside down.

[budm]

Re: Element elefw605 power issue maybe?

https://www.badcaps.net/forum/attach...5&d=1558240639
Are you sure you did not get the PS-ON and the 5VSB pin mixed up? More likely the PS-ON is 3V and the 5VSB is 5V because all the Voltages are generated by the same transformer, the +5V (swithed +5V) is the same +5V that is fed to the +5VSB, it is just being switched that all. The main board cannot be sending out +5V to the PS-ON pin if the +5VSB is only 3V for running the main board.

[Demonata08]

Re: Element elefw605 power issue maybe?

https://www.badcaps.net/forum/attach...5&d=1558240639
Are you sure you did not get the PS-ON and the 5VSB pin mixed up? More likely the PS-ON is 3V and the 5VSB is 5V because all the Voltages are generated by the same transformer, the +5V (swithed +5V) is the same +5V that is fed to the +5VSB, it is just being switched that all. The main board cannot be sending out +5V to the PS-ON pin if the +5VSB is only 3V for running the main board.

Unfortunately im quite positive of my reading. I did test my theory that the set is trying to turn on as soon as its plugged in and that does seem to be the case. I unplugged the main and all voltages were 0 basically except +5VSB which was now 5vs

[Demonata08]

Re: Element elefw605 power issue maybe?

Quick update. I took out the 5vsb pin from the ribbon and plugged it in. Sure enough the power supply is quiet. Whatever the problem is im pretty sure its on that line.

Its very confusing to me that 5vsb would be there at all if its not in standby. But instead something brings it to 3.3v

[budm]

Re: Element elefw605 power issue maybe?

See post #30.

[budm]

Re: Element elefw605 power issue maybe?

Quick update. I took out the 5vsb pin from the ribbon and plugged it in. Sure enough the power supply is quiet. Whatever the problem is im pretty sure its on that line.

Its very confusing to me that 5vsb would be there at all if its not in standby. But instead something brings it to 3.3v

If you disconnect the cable from the power supply board to the main board, what do you get on the Standby +5SB pin? That is standby power supply that is always running to supply the power to run the main board. Standby Voltage will always be present as long as there is AC feeding the TV. No standby Voltage then the rest of the switched power supply will not be on since there will be no Voltage to run the main board so the main board cannot send out the PS-ON signal, that is why it is quiet.
The main board requies the +5VSB to keep the board alive so it can receive the ON command signal from the remote or from power switch, the TV will also remember the last power state when it lose AC power.

BTW: "Its very confusing to me that 5vsb would be there at all if its not in standby." I do not understand what you mean. You do not expect Voltage at the +5VSB pin if the TV is NOT in standby?

[budm]

Re: Element elefw605 power issue maybe?

https://www.badcaps.net/forum/attach...5&d=1558240639
BTW, the BL-ON only shows 0.35V, is that right when TV is working? You do see the backlights come on, correct?
How about the Adj (dim) control signal?

[Demonata08]

Re: Element elefw605 power issue maybe?

If you disconnect the cable from the power supply board to the main board, what do you get on the Standby +5SB pin? That is standby power supply that is always running to supply the power to run the main board. Standby Voltage will always be present as long as there is AC feeding the TV. No standby Voltage then the rest of the switched power supply will not be on since there will be no Voltage to run the main board so the main board cannot send out the PS-ON signal, that is why it is quiet.
The main board requies the +5VSB to keep the board alive so it can receive the ON command signal from the remote or from power switch, the TV will also remember the last power state when it lose AC power.

BTW: "Its very confusing to me that 5vsb would be there at all if its not in standby." I do not understand what you mean. You do not expect Voltage at the +5VSB pin if the TV is NOT in standby?

No because this tv is never in standby. As soon as you plug it in it gives the signal to turn on. But the backlights dont turn on or anything. Just the voltage from the pboard shows it to be on.

The only way i can get it to standby is unplugging the main. In which it shows 5vsb as 5vs. With the main plugged in it shows 3.3v on 5vsb. Im not experienced. I was just commenting on how i figured thr 5vsb would not be there if the tv wasnt in standby.

[Demonata08]

Re: Element elefw605 power issue maybe?

https://www.badcaps.net/forum/attach...5&d=1558240639
BTW, the BL-ON only shows 0.35V, is that right when TV is working? You do see the backlights come on, correct?
How about the Adj (dim) control signal?

I have not seen the tv come on at all since it last went out. The problem was getting progressively worse and i suppose the last time it was turned off was it for it. If i have patiences i can unplug it a bunch of times will hitting the power button and it might come on. But its not a fix. Next time it goes off itll be in the same situation

[Demonata08]

Re: Element elefw605 power issue maybe?

If you disconnect the cable from the power supply board to the main board, what do you get on the Standby +5SB pin? That is standby power supply that is always running to supply the power to run the main board. Standby Voltage will always be present as long as there is AC feeding the TV. No standby Voltage then the rest of the switched power supply will not be on since there will be no Voltage to run the main board so the main board cannot send out the PS-ON signal, that is why it is quiet.

The main board requies the +5VSB to keep the board alive so it can receive the ON command signal from the remote or from power switch, the TV will also remember the last power state when it lose AC power.

BTW: "Its very confusing to me that 5vsb would be there at all if its not in standby." I do not understand what you mean. You do not expect Voltage at the +5VSB pin if the TV is NOT in standby?

Sorry for the triple post but now i have an idea. If what you said is true and the board requires the 5vsb at all times but when its under a load it drops to 3.3 is that not a power issue then. Which might be the source of the buzzing?

[R_J]

Re: Element elefw605 power issue maybe?

Monitor the 5v standby pin and try heating some of the small electrolytics on the primary side and see if the voltage comes up a bit, this power supply might be operating in burst mode while in standby and it could just be one of the feedback run caps is weak. these small 1~10µf caps never look bad but can dry up and goe basically open

The standby voltage must be there to operate the microprocessor so it knows that you pushed the power button. The power button connects to the micro and the micro issues the Power On command to the power supply

[Demonata08]

Re: Element elefw605 power issue maybe?

Monitor the 5v standby pin and try heating some of the small electrolytics on the primary side and see if the voltage comes up a bit, this power supply might be operating in burst mode while in standby and it could just be one of the feedback run caps is weak. these small 1~10µf caps never look bad but can dry up and goe basically open

The standby voltage must be there to operate the microprocessor so it knows that you pushed the power button. The power button connects to the micro and the micro issues the Power On command to the power supply

I will do that. But how would that work if the tv is automatically trying to turn on when its plugged in

[R_J]

Re: Element elefw605 power issue maybe?

How would WHAT work? It likely won't make the tv work, but if you find a suspect cap, you can replace it and then see if the standby stays at 5 volts.

If you want to check the power supply properly you need to have a scope and an isolation transformer so you can trace the fault in the primary. Or you could use a cap esr meter to check the caps to rule them out.

[Demonata08]

Re: Element elefw605 power issue maybe?

How would WHAT work? It likely won't make the tv work, but if you find a suspect cap, you can replace it and then see if the standby stays at 5 volts.

If you want to check the power supply properly you need to have a scope and an isolation transformer so you can trace the fault in the primary. Or you could use a cap esr meter to check the caps to rule them out.

All the caps checked out except maybe one. Some of the 10uf 50v smaller caps were showing around 1 esr.

The bigger 450v 80uf was showing 5esr so i went ahead and replaced that. It still has the same problem but the buzzing i was hearing is drastically reduced now.

[R_J]

Re: Element elefw605 power issue maybe?

Did you look at this thread? the power supply is different but maybe the main board is the same, he had an issue with some caps on the main that might be causing the problem https://www.badcaps.net/forum/showth...light=elefw605

[Demonata08]

Re: Element elefw605 power issue maybe?

Did you look at this thread? the power supply is different but maybe the main board is the same, he had an issue with some caps on the main that might be causing the problem https://www.badcaps.net/forum/showth...light=elefw605

musta missed that one. I followed the advice on checking the resistances. I'm really not sure i'm doing it right. i have the meter grounded to the chassis and im just doing a simple resistance check on the pinout this is the results.

5v .45k
5v .45k
PS_ON 20k
5vsb 20k
12v 1k

the ps_on and 5vsb are weird. they start in the millions and they just keep going down or they start in the thousands and keep rising. the other ones are stable and dont move.