Vizio VO42L FHDTV10A will not turn on...

[PlainBill]

Re: Vizio VO42L FHDTV10A will not turn on...

PlainBill, I finally had a chance to measure the voltages and the value of the resistor. Pin 6 measures 8.4v, pin 8 measures 13.3v, and all other pins measure 0v. For the heck of it I also measured pin 7 which indicated 0.1v.

Also, resistor R907 is a 100Kohms that measured 99.4Kohms.

Assuming this is equivalent to the NCP1207, the SMPS controller is bad.

The key is pin 6. The way this circuit works is it uses the rectified line voltage at pin 8 to charge the Vcc cap connected to pin 6. When the voltage at pin 6 reaches 12 V, the controller begins driving the power FET. Since the voltage at pin 6 never reaches 12V, the controller never starts. The voltage at pin 8 is somewhat lower than I would expect for a good IC, also indicating a problem with the IC.

PlainBill

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

Thanks PlainBill. Now I just need to find where I can purchase from or find another power supply I can remove from.

[PlainBill]

Re: Vizio VO42L FHDTV10A will not turn on...

Thanks PlainBill. Now I just need to find where I can purchase from or find another power supply I can remove from.

That's the rub. It's been pretty well established that even 'identical' parts from different manufacturers can have different characteristics. Given the sparse information on the original part, I'd be more comfortable in using the Fuji part. A Google seaqrch will identify suppliers, but they are all surplus dealers, looking to sell hundreds or thousands.

However, since the NCP1207 is readily available on eBay, I would consider using that.

PlainBill

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

I have ordered 5 free samples of NCP1207A and NCP1207B directly from ON Semiconductors, paying only shipping/handling. I didn't think to check eBay, but looking what they had I'm paying about the same price.

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

Received the NCP1207A chip today. Hopefully I'll be able to install it today or tomorrow and see if the power supply works.

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

Well I soldered the NCP1207A in place of the 2A07D12_5531. I attempted to measure 5VSB, but no luck... still reading 0V.

The following are the voltages on the NCP1207A chip:
Pin 2: 3.5V
Pin 6: 5.5V
Pin 8: 9.9V
All other pins measure 0V.

I'm loosing hope

[PlainBill]

Re: Vizio VO42L FHDTV10A will not turn on...

Me too. I thought we had identified the problem. I'm out of ideas.

PlainBill

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

Is it possible that the 2SK3569 MOSFET might be shorted or open i.e. no good.

[jetadm123]

Re: Vizio VO42L FHDTV10A will not turn on...

Is it possible that the 2SK3569 MOSFET might be shorted or open i.e. no good.

1) The 2SK3569 is driven by pin 5 of the NCP1207, correct? If yes, with power off, go ahead and check it for shorts.

2) The startup cap connected to pin 6 (VCC) of the NCP1207, was that ever changed? These small caps seldom show any physical signs of failure.

3) Pin 6 voltage across the startup cap is supplied by a diode and resistor(s). Try checking the diode for shorts,the resistor(s) for out of range values and any other component connected to pin 6.

[edtv]

Re: Vizio VO42L FHDTV10A will not turn on...

Anyone have success repairing this issue?

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

I haven't yet. It's currently on the back burner for now.

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

I spent some more time on the power supply. I found 2 resistors blown each with the following markings: 0.1ohm, F1J. Based on some searching I did, I believe they are Fuse Resistors. Both resistors are in parallel, one end goes to the (+) side of the 400V cap, which measures 168VDC, and the other end goes to pin 8 of the SMPS, which measured 14vdc or so (don't remember exactly). Now I need to find a replacement for those 2 resistors. Any thoughts what the F1J means on the resistor?

The 2 resistors are the ones in the above picture left of the big transformer below the "K3569".

[alexanna]

Re: Vizio VO42L FHDTV10A will not turn on...

Well I soldered the NCP1207A in place of the 2A07D12_5531. I attempted to measure 5VSB, but no luck... still reading 0V.

The following are the voltages on the NCP1207A chip:
Pin 2: 3.5V
Pin 6: 5.5V
Pin 8: 9.9V
All other pins measure 0V.

I'm loosing hope

I am working on a sharp television,and it's using the FA5531 IC to start the power,here is a service Manual with a wiring diagram.
http://elektrotanya.com/?q=showresul...oria=&kat2=all

[alexanna]

Re: Vizio VO42L FHDTV10A will not turn on...

I am working on a sharp television,and it's using the FA5531 IC to start the power,here is a service Manual with a wiring diagram.
http://elektrotanya.com/?q=showresul...oria=&kat2=all

This is a different television and it's only 22" but it's using the FA5531 controller for IC 501.
Originally this set was dead, on pin 8 of IC501 I was seeing 32volts and on pin 6 it was down to about 1.4 volts. Also the large capacitor would not bleed down by itself, I had a few exciting moments!
I was lucky enough to have picked up a television to salvage that was using the FA5531 controller.
After replacing a .22 ohm bleed resistor and FA5531, the voltages I noticed on a working power supply were 74 volts on pin8 an 17 volts on pin 6.
The FA5531 is for sale on Ebay but it's expensive, I am thinking about ordering the NPC1207AP to see if it's a good substitute it sure is a lot cheaper. I just haven't made my mind up yet.

[richr69]

Re: Vizio VO42L FHDTV10A will not turn on...

Alexanna, thanks for the information, however, my attempt in getting the TV working is over.

In the process of attempting to fix the power supply, I was able to purchase a used power supply off of ebay. I connected the new (used) power supply and the TV powered on, which was exciting. Unfortunately, the LCD screen was cracked, which I did not know when I started this whole project. What a disappointment.

Thanks to everyone who provided suggestions/help.

[Dgtech]

Re: Vizio VO42L FHDTV10A will not turn on...

It's not a total loss. Sell the boards that you know are working on Ebay. You will make up a good ammt of money.

[kb48]

Re: Vizio VO42L FHDTV10A will not turn on...

PlainBill, I finally had a chance to measure the voltages and the value of the resistor. Pin 6 measures 8.4v, pin 8 measures 13.3v, and all other pins measure 0v. For the heck of it I also measured pin 7 which indicated 0.1v.

Also, resistor R907 is a 100Kohms that measured 99.4Kohms.

Delaing with the DPS284AP supply which is similar. I have been looking at the 26 pin chip, which seems to run the Main Supply side, of 24 and 12V sources.
I cannot see any numbers to ID that chip, which I think is bad.

The PS comes on with the 5V ok, but nothing else.
When I attempt to bias the PS_ON with either 3.3 or 5V it seems to engage the relay which then kills power to the input I.E. 164VDC primary. That relay is in series with 110 AC but it is setup normally closed. So it seems then that the set turns to standby when PS_ON goes high.

This has been with testing it outside of the set, on an insulated surface and I yanked the AC input and cord, and this is what I get.

So if anyone here has a working DPS284AP that they are testing out, and can tell me what voltages appear on the 16 pin chip I would love to know.
I guess I will just end up in the gamble of purchasing a supply when I can.
Sadly if it turns out that there are other troubles such as mainboard or inverter I will have wasted my money as I am sure there is no return or not worth returning and losing money.
If I could get the PS to come on even just long enough to see all the working voltages just once, then I could rule out any problem with the mainboard.
The mainboard processor does get fairly warm and even warmer when power is pressed but since nothing comes out of the PS other than the 5V all the time, hard to say if there are other issues or not.

VIZIO light is white all the time. I got it to light up the 5.1 red led (SRS sound? logo) in the center speaker grille. I guess that shows some sign of activity...
Nothing else runs of course.
No blown fuses anywhere.

[erics_32751@yahoo.com]

Re: Vizio VO42L FHDTV10A will not turn on...

I'm troubleshooting the same DPS-260HP-1 A power supply. It appears that Diode D904 is burnt. Any idea where I might find a replacement?

[CoppellTVRepair]

Re: Vizio VO42L FHDTV10A will not turn on...

I realize this comment is a bit too long after the events in this thread, but still in case for those who will come accross it for their own needs:

IC FA5531 can be bought at http://www.coppelltvrepair.com.

Our main business is actually module repairs, i.e. we do repair the whole board for individuals and companies, but we sell some of the commonly needed components to help our bottom dollar.

We can sometimes help with identifying a component or giving a hit, but we can't possibly afford to promise free troubleshooting or even 100% answers.
It's busy enough as it is.

I'd also like to add that I read this thread and the troubleshooting process in it is going the right way. It is a perfect illustration how frustrating it is to help others remotely, though...it is simply inefficient most of the time!

[joro80]

Re: Vizio VO42L FHDTV10A will not turn on...

Hi, i have a problem with ncp1207a, never get 12v on pin 6. ILPI-025 power supply for Acer monitor, all in mosfet gate was burned, check and replaced bad parts, orinal pwm is ncp1337 but i have 1207a.Someone has an idea how to start this chip?
Tanks.