Toshibia 40rv525u Green Blinking light and questions about Caps!!

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Sorry, I haven't gotten back to anyone on here it's been a difficult month, I have had two Family members die. And my regular work has been extremely busy, which I guess i should be thankful for.

Ok I tested and the PWR was measuring around 4.3v. However, none of the other outputs had any readings.

Also, I probed the +5v pin before the resistor, and found that it wasn't stable. Without, the resistor its around +5.06v but with the resistor it goes all over the place from +4.16v to +4.80v, does that indicate a problem with the power board?

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Sorry, I haven't gotten back to anyone on here it's been a difficult month, I have had two Family members die. And my regular work has been extremely busy, which I guess i should be thankful for.

Ok I tested and the PWR was measuring around 4.3v. However, none of the other outputs had any readings.

Also, I probed the +5v pin before the resistor, and found that it wasn't stable. Without, the resistor its around +5.06v but with the resistor it goes all over the place from +4.16v to +4.80v, does that indicate a problem with the power board?

Some types of power supply are unstable with no load, this is expected and is not really a problem as most of the time, they have a load. Are you saying when PWR signal is on, the power supply is not starting up?

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yep as far as I can see. The side of the resistor that is connected to the PWR pin is measuring 4.3v. This would indicate that the problem is with the psu right and not the mainboard. What should i test next?

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yep as far as I can see. The side of the resistor that is connected to the PWR pin is measuring 4.3v. This would indicate that the problem is with the psu right and not the mainboard. What should i test next?

Try using the resistor to pull the PWR pin down, some PSUs switch on when this is a low signal.

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Try using the resistor to pull the PWR pin down, some PSUs switch on when this is a low signal.

Thats what I have been doing right? You said to hook the resistor up between +5v and PWR. Not sure what you mean by "pull the PWR pin down?" Thanks!

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Thats what I have been doing right? You said to hook the resistor up between +5v and PWR. Not sure what you mean by "pull the PWR pin down?" Thanks!

Connect one end to PWR, the other to a spare GND pin.

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Nope nada, nothing nothing reads power except the +5v rail, conected PWR to Ground and all outputs are 0.0v. Thanks!

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Nope nada, nothing nothing reads power except the +5v rail, conected PWR to Ground and all outputs are 0.0v. Thanks!

This confirms you have a faulty power supply. What tests have you done so far on this power supply? Also what value resistor were you using?

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

I was using a red violet red that is 2.7k right?

I have only done what was suggested in this thread plus a few my my own.

Shortened List

Test Fuse Good

Listed and Checked all Pins for power. Results the only pins which had power were +5v and the PWR and ACD which went from 0v to 2.7v in Snyc with the Front Panel LED.

Checked 3 voltage regulators on the main board. Never really got an OK on these. POST# 25

Tested Diodes POSTS# 48,49,52.

Tried to jump supply using the resistor above from the PWR pin on both GND and +5v pins. Power Supple still did not read voltage.

Looking at the layout of this power supply, it's clear that there is no startup cap for the main rails (as the primary of the main transformer has just one winding); the Vcc for the main controller (5V/12V/24V) is developed from the standby supply and as that is working, it's unlikely to be the problem.

Umm about this post, since I am not getting anything on 12v or 24v does that indicate something wrong with the Standby part of the power supply?

Thanks for all the help so far.

[PlainBill]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

I was using a red violet red that is 2.7k right?

I have only done what was suggested in this thread plus a few my my own.

Shortened List

Test Fuse Good

Listed and Checked all Pins for power. Results the only pins which had power were +5v and the PWR and ACD which went from 0v to 2.7v in Snyc with the Front Panel LED.

Checked 3 voltage regulators on the main board. Never really got an OK on these. POST# 25

Tested Diodes POSTS# 48,49,52.

Tried to jump supply using the resistor above from the PWR pin on both GND and +5v pins. Power Supple still did not read voltage.



Umm about this post, since I am not getting anything on 12v or 24v does that indicate something wrong with the Standby part of the power supply?

Thanks for all the help so far.

The voltage readings in post #25 indicate only that the regulators aren't getting power. In Posts #48-52 you did not what range you were using, or what diode was being tested. The picture is too poor to read component identifiers.

No voltage from the 12 volt and 24 volt supplies may indicate a problem with the main supply. IF the resistor pulled PSON to ground or to 5V, there is definitely a problem with the main supply.

PlainBill

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Whilst using the 2.7k resistor, can you measure the PWR pin when connected to 5V and GND?

It sounds like the AC detect may be faulty but I'm not sure.

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Whilst using the 2.7k resistor, can you measure the PWR pin when connected to 5V and GND?

It sounds like the AC detect may be faulty but I'm not sure.

But wouldn't that only be on the mainboard? The power supply should still start up with the resistor right? Or is this thinking incorect?

As for the diode test plain bill I was using the diode test function on the multimeter. And the test was done With the order of pins in the picture, Starting with 1 and the top of the board and ending with three at the bottom of the Diode.

Thanks!

PS should I try caps now what else can I test?

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

But wouldn't that only be on the mainboard? The power supply should still start up with the resistor right? Or is this thinking incorect?

Maybe the resistor is too high of a value. If the voltage is genuinely going close to 5V or 0V, it's most likely the PSU that is at fault.

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

What value should I try? As I said it was around 4.30, but also the the 5v rail became unstable with the values all over the place even as low as 4.1v, with the resistor connected.

What other components can I test on the PSU

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

What value should I try? As I said it was around 4.30, but also the the 5v rail became unstable with the values all over the place even as low as 4.1v, with the resistor connected.

What other components can I test on the PSU

You have to do a bit of guesswork because we don't know the input impedance of the PSU. Do you mean PWR measured 4.3V?

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yes, the Side of the Resistor that was connected to the PWR pin measured 4.3v

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yes, the Side of the Resistor that was connected to the PWR pin measured 4.3v

And when grounded, did it measure nearly zero?

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yes there was no apparent voltage. Meter just read 0.00 - 0.01v

[tom66]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Yes there was no apparent voltage. Meter just read 0.00 - 0.01v

Good. This narrows the problem down to the power supply. I like debugging power supplies; they are far easier than a motherboard and often quite cheap to repair.

From the look of this power supply, it seems that two capacitors are used to double the incoming 115V AC to 230V AC. I can only think they must do this because they can use similar parts that they might use on the 230V AC version. It's rather odd...

This TV does not have a PFC section. I don't think PFC is required in the USA so this is probably why. That means one less thing to debug, which is good.

Check that each of these capacitors has around 160V across it. Careful, this is high voltage, and can give a very nasty shock.

[ComputerGeek]

Re: Toshibia 40rv525u Green Blinking light and questions about Caps!!

Unless you guys have any other ideas, I think I am going to replace the Caps.

What is suggested as a replacement?

I was only going to replace all the Caps on the board except for the list below, unless you suggest otherwise.

Leaving List

All Film/Mylar Caps
All Ceramic Caps
The Two Main Filter Caps
The two 1500uf 10v YXG Series 105C Rubycon's


Replacing List

All are Nippon Ky Series 105C Capacitors
One 1000uf 25v
Three 1000uf 35v
Two 100uf 25v caps.
One 10uf 50v
One 22uf 50v
One 47uf 25v

Is that OK should I order any of the other ones?

Also, I was just going to combine the 1000uf 25v
and 1000uf 35v Caps and just get a lot of 25 or so of 1000uf 35v Caps is that ok?

What is suggested as a replacement, should I get the same Series and Brand? I would like to try to get them all at Digi-Key.

Thanks!