E470VA with a PLHH-Y009A - no power

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

I would order more than one STRWxxxx in the event that the replacement blows again.

Sounds like a good idea.

If you go ahead using glass fuses then slide a sleeve over it in the event that if it ruptures it does'nt spray glass everywhere.

Yes, I can do that. I will not be soldering those temporary fuses to the board. They will be used with alligator clips only, just to test if the TV is still causing blowouts. The permanent fuse will be soldered in later once repairs are done (if they get done).

I would have thought you could obtain these items from US suppliers or on Ebay.

That is an eBay shopping list.

[dick_barton]

Re: E470VA with a PLHH-Y009A - no power

What does the standard SpeedPak from China/Hong Kong/ Taiwan refer to?

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

What does the standard SpeedPak from China/Hong Kong/ Taiwan refer to?

Shipping from China. Tons of stuff on eBay ships from China. It's not only US sellers.

You said I could get them from US suppliers or on Ebay. These are the latter.

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

What does the standard SpeedPak from China/Hong Kong/ Taiwan refer to?

I replaced the 6-pin component discussed before and the TV still blew the same fuse

Anything else that can be done? If not, I guess I'll just scrap it and keep the boards for parts for a future project.

[nomoresonys]

Re: E470VA with a PLHH-Y009A - no power

Build yourself one of these, don't have to worry about blowing fuses: https://www.youtube.com/watch?v=k5oNQ1etN2c

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Build yourself one of these, don't have to worry about blowing fuses: https://www.youtube.com/watch?v=k5oNQ1etN2c

Right now my problem is I don't know what to check next.

[R_J]

Re: E470VA with a PLHH-Y009A - no power

It is very likely that the standby ic, U101 is the problem, check the resistance between pins 7or8 and pin 1. For testing you can leave ic501 out of the board, and you could also remove one end of both jumper wires JW59 & JW78, these feed the main DC to the backlight mosfets. With the ic & the jumpers removed you should have 5.2V standby voltage, If the fuse still blows it is likely U101 is bad.

I would also use a 60~100watt incandescent lamp in series with the main ac line, this will help in finding the short.

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

It is very likely that the standby ic, U101 is the problem, check the resistance between pins 7or8 and pin 1. For testing you can leave ic501 out of the board, and you could also remove one end of both jumper wires JW59 & JW78, these feed the main DC to the backlight mosfets. With the ic & the jumpers removed you should have 5.2V standby voltage, If the fuse still blows it is likely U101 is bad.

I would also use a 60~100watt incandescent lamp in series with the main ac line, this will help in finding the short.

For testing the U101 resistances on the pins, which pins are those (having trouble finding pin numbers) and do you want it tested while the item is still soldered into the power board? See image attached. I assume that's the one you want tested.

[R_J]

Re: E470VA with a PLHH-Y009A - no power

Pin 1 is marked with the dot. pin 6 is not used (missing)

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Pin 1 is marked with the dot. pin 6 is not used (missing)

Did I number them right (see attached)?

While soldered to board?

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Pin 1 is marked with the dot. pin 6 is not used (missing)

Between the pin next to the dot and the one across from it (8 I assume) the resistance is 2.7 Ohms, so I guess it's fried? This is with the item still on the board, though.

[R_J]

Re: E470VA with a PLHH-Y009A - no power

Yes the numbers are correct, they have Datasheets on these ic's If you search for the ic number and look at the datasheet you will see there is an internal mosfet, and 2.7Ω indicates it is shorted. There could be something else shorted but it is likely the ic, remove the ic and check the pins again to be sure.

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Yes the numbers are correct, they have Datasheets on these ic's If you search for the ic number and look at the datasheet you will see there is an internal mosfet, and 2.7Ω indicates it is shorted. There could be something else shorted but it is likely the ic, remove the ic and check the pins again to be sure.

Will do. I assume it will be bad, but will desolder and check just in case before ordering.

Do you know any electronics that contain this or a good place to get it cheap? It's $2.69 from China, but it takes a month

[R_J]

Re: E470VA with a PLHH-Y009A - no power

Looks like mouser & digikey carries them, (if it is a VIPER27LN) but they are also 5 month lead time. So China might be quicker, get a few just in case, China delivery can be fast at times.

I would also replace C102, it might be ok but it could be weak. I think it is a 10µf/50v

The VIPER27LN is for 60kHz operation (I believe this is the one on your board)
The VIPER27HN is for 115kHz operation

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Looks like mouser & digikey carries them, (if it is a VIPER27LN) but they are also 5 month lead time. So China might be quicker, get a few just in case, China delivery can be fast at times.

I would also replace C102, it might be ok but it could be weak. I think it is a 10µf/50v

The VIPER27LN is for 60kHz operation (I believe this is the one on your board)
The VIPER27HN is for 115kHz operation

I just tested it with the piece off and there is no continuity between 1 and 7/8. The continuity was on the board itself.

[R_J]

Re: E470VA with a PLHH-Y009A - no power

I just tested it with the piece off and there is no continuity between 1 and 7/8. The continuity was on the board itself.

Then there is something shorted on the line that is connected to pins 7/8, It should not be too hard to find.
Lift JW59 & JW78, still a short? Then lift FB101, Lifting these jumpers will isolate where the short is.

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

Then there is something shorted on the line that is connected to pins 7/8, It should not be too hard to find.
Lift JW59 & JW78, still a short? Then lift FB101, Lifting these jumpers will isolate where the short is.

These can literally be lifted or do they need to be resoldered?

[R_J]

Re: E470VA with a PLHH-Y009A - no power

These can literally be lifted or do they need to be resoldered?

These parts are SOLDERED to the board, they can't just be lifted. Just unsolder one end, that way you can eliminate certain parts of the circuit, otherwise you would need to remove every component on that line to find the shorted part.

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

These parts are SOLDERED to the board, they can't just be lifted. Just unsolder one end, that way you can eliminate certain parts of the circuit, otherwise you would need to remove every component on that line to find the shorted part.

I lifted JW59: still a short between 1 and 7/8.
I lifted JW78 (without putting back JW59): no short between 1 and 7/8.

I did not do anything with or even look for or identify FB101 since I assume it's not necessary at this point?

[primuspaul]

Re: E470VA with a PLHH-Y009A - no power

These parts are SOLDERED to the board, they can't just be lifted. Just unsolder one end, that way you can eliminate certain parts of the circuit, otherwise you would need to remove every component on that line to find the shorted part.

I should add that that behavior (short, no short, as described in the previous post) is with the fuse I mentioned before effectively off the board because it shorted the last time I tested something, but I assume you knew this since I mentioned it.

Anyway, let me know what those symptoms mean to you - what piece you think is broken.