Vizio E65X-C2 no 5V_Stdby

[Spork Schivago]

Hi!

I have a Vizio E65X-C2 with no 5V_Stdby. I've uploaded a couple pics, but couldn't get the lighting right.

I found a bad diode, DM855, and the diode reads:

LT5135
SB5150

I believe the part number for that diode is SB5150. Could someone help me find a compatible diode for this PSU?

There are three diodes in that section and they're connected to the output of a transformer. I'd like to understand this transformer a little better. It looks horrible, like a child wound it.

I suspect this IC might be dead, ICB801, but I am having trouble locating a datasheet. Aliexpress is selling a lot of 5 and have it listed as a voltage regulator.

Does anyone know what this IC is? Does any one know the purpose of the transformer? I'd love to learn how to test it. I've seen videos on how to test various transformers, but when I check continuity on the input side, I see ~0 ohm resistance between certain pins and same for the output side.

Thanks!

[CapLeaker]

Re: Vizio E65X-C2 no 5V_Stdby

If it is a SB5150, any 150v 5A schottky diode will do. You could put a 200V 5A Schottky diode in the too, if you want.
Digikey has some SR515 or SR520.

[R_J]

Re: Vizio E65X-C2 no 5V_Stdby

Have you checked the fuse FB801s and RB801? The transformer will be ok, you are measuring the dc resistance of the transfomer wire, it will read low
If only one diode was bad and you have it removed, try the power supply and see if you have 5 volts standby, It should operate with just the two diodes for testing as all three are in parallel, If you are lucky the shorted diode only took out the fuse for the ic

[CapLeaker]

Re: Vizio E65X-C2 no 5V_Stdby

I believe that ICB801 (2a153d) IC is a PWM made by Sanken. Here are the specs for it:
http://www.datasheet-pdf.com/PDF/STR...-Sanken-938235

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

Have you checked the fuse FB801s and RB801? The transformer will be ok, you are measuring the dc resistance of the transfomer wire, it will read low
If only one diode was bad and you have it removed, try the power supply and see if you have 5 volts standby, It should operate with just the two diodes for testing as all three are in parallel, If you are lucky the shorted diode only took out the fuse for the ic

Yes sir. The fuses where the first things I checked. I checked FB801, but I didn't check RB801 yet. I planned on doing that and was working on that area of the board (that I suspected was bad for one reason or another). I checked the fuse, FB801, and the main fuse F001 first. Then I checked the various voltages and seen no 5V_STDBY.

After that, I started with the diodes in area that I'm currently working on. Yesterday was my birthday, and the day before my anniversay, so I didn't do any work on this, minus sending some pics here. I will check the other components, especially those resistors, in that part of the circuit. I suspect RB802 might be bad as well. Looks a little funky, but it might be okay.

Why did the diode short out though? I thought it had something to do with that transformer...from looking at how to test transformers on-line, on the primary, I thought the resistance should be higher going from the first pin to the 2nd, then the first to the 3rd, etc. It's not though, it all reads around 0 ohm resistance. I thought perhaps that IC is shorted out.

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

If it is a SB5150, any 150v 5A schottky diode will do. You could put a 200V 5A Schottky diode in the too, if you want.
Digikey has some SR515 or SR520.

I couldn't find a through hole schottky diode rated for 150v 5A on digikey though. I will try checking a little harder. Maybe I over looked the SR515.

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

I believe that ICB801 (2a153d) IC is a PWM made by Sanken. Here are the specs for it:
http://www.datasheet-pdf.com/PDF/STR...-Sanken-938235

I thought maybe it was and came across the same datasheet. I wonder why this chip has that D at the end of 2A153D and the datasheet don't mention it. That's what threw me off a little. Thanks!

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

If it is a SB5150, any 150v 5A schottky diode will do. You could put a 200V 5A Schottky diode in the too, if you want.
Digikey has some SR515 or SR520.

Yup, I think I found it:

https://www.digikey.com/product-deta...GCT-ND/7359325

I don't know how I missed that. I did queries like 150V 5A Schottky barrier diode, then I tried using filters on digikey to filter the results. I kept getting the wrong package type. Thanks!!!!!!

[CapLeaker]

Re: Vizio E65X-C2 no 5V_Stdby

you're welcome

[Unspun01]

Re: Vizio E65X-C2 no 5V_Stdby

The 2A153D IC has VCC at pin 2 and Ground at pin 3.

With TV unplugged:

Measure for a short between pins 2-3.

In fact, measure for shorts between pin 3 and all other pins of this IC.

If there is no short, then plug TV in and measure the voltage between pins 2-3.

Do you get voltage on Vcc pin 2?

[R_J]

Re: Vizio E65X-C2 no 5V_Stdby

Why did the diode short out though? I thought it had something to do with that transformer...from looking at how to test transformers on-line, on the primary, I thought the resistance should be higher going from the first pin to the 2nd, then the first to the 3rd, etc. It's not though, it all reads around 0 ohm resistance. I thought perhaps that IC is shorted out.

The transformer operates at high frequency a/c (67khz) The ic and internal fet switch the 160 volts dc across the primary at 67khz, this causes an induced voltage in the secondaries, one secondary is used for the small run voltage for the ic's VCC. The other secondary is for the 5volt standby output
If the ic's fet shorted, it would apply 160v dc across the primary, Thats when you would have a problem as 160v dc across 1Ω primary would be 160 amps, the small fuse blows, if the fuse was not there the top would come off the ic (bang).
So if the small fuse is ok, and that low value resistor is ok, I suspect the ic is also ok as it does have over current protection.
As for the diode? If there is no short on the 5 volt standby line OR the 5 volt switched line, it was likely just the diodes time.

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

I think this might be a MOSFET, and could be bad. Traced the bad diode to this QM864, but I cannot read hardly anything off the chip.

In the second picture I upload in this post, I outlined in a red box where the bad diode is.

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

The 2A153D IC has VCC at pin 2 and Ground at pin 3.

With TV unplugged:

Measure for a short between pins 2-3.

In fact, measure for shorts between pin 3 and all other pins of this IC.

If there is no short, then plug TV in and measure the voltage between pins 2-3.

Do you get voltage on Vcc pin 2?

When my wife gets home from work, I will do that.

With no power, 1 and 3 show around 0 ohm resistance. 2 and 3 though jumps around. I was reading the datasheet and seen it had OLP and OCP. I do not think the IC is damaged anymore. I will still test it when my wife gets home though.

[R_J]

Re: Vizio E65X-C2 no 5V_Stdby

Use some alcohol or similar to clean the mosfet, you should be able to see the niumber, It could be a AOD4185
That mosfet is for the switched +12volts, Looks like the standby 5 volts comes from DM856 and CM821

See if the markings are similar to this

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

Use some alcohol or similar to clean the mosfet, you should be able to see the niumber, It could be a AOD4185
That mosfet is for the switched +12volts, Looks like the standby 5 volts comes from DM856 and CM821

See if the markings are similar to this

You are good. It is the AOD4189. I am going to replace it anything. It tested good, but it's cheap, price wise, and I wouldn't mind having a couple laying around.

I believe if I replace that failed diode, this TV will work again. I need to buy solder. I'm looking at the Kester 275 series KE1893-ND (on DigiKey)

It's Lead-Free, Silver Bearing, but contains Halogen :-/. It's part number 2470687609. Here's a link to Kester's site:

https://www.kester.com/products/prod...lux-cored-wire

I wonder if it's too late to change my DigiKey order and get the 268 Flux-Cored Wire halogen-free / zero-halogen solder...

[CapLeaker]

Re: Vizio E65X-C2 no 5V_Stdby

stay away from that lead free crap.

[R_J]

Re: Vizio E65X-C2 no 5V_Stdby

That 12 volts source uses 3 diodes in parallel, one was shorted, If you have it removed, try the power supply. at least to see if you have 5 volts standby. If you turn on the tv, the other 2 diodes can supply enough current to see if the tv will work, just don't leave it running. just a short test
Or you can test just the power supply without the main board connected to make sure you have your 5 volts standby, then use a 1k resistor between 5VSB and PS_ON to turn on the 12 volts

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

I forgot to update the thread. I had originally tried powering it with the two diodes in parallel, before you I read your post here, and had 5V_STDBY. I tried turning it on quick like, but it didn't power up. I suspect it was going through some start-up phase or something. I didn't keep it plugged in long.

I received the replacement components on Thursday, installed them, TV works fine. I gave it back to the customer.

I know there was no surge now that caused this. I ended up replacing the MOSFET, two of the SOT-220-3 schottky diodes, and the three through-hole schottky diodes. Works like a charm. Not sure how long the LEDs will last in this TV, but I suspect that will probably be the next problem.

[Spork Schivago]

Re: Vizio E65X-C2 no 5V_Stdby

stay away from that lead free crap.

Why do you not like lead free solder? I seem to like it. Is it just because you find it harder to work with? Because it requires higher temps to melt?

Thanks!