Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

[tom66]

Got another one of these with the FETs on the SN toast. The pass FETs and the ER IGBT test ok. The last set had an issue with ER IGBTs but this one looks to have survived, will have to test properly to be sure.

Green flashes then dead with relay click if SN connected.
7 SOS with SN power disconnected.
8 SOS with SN power and control ribbon disconnected.

Anyone got any good sources for the 30F131s?

I plan to put this one in my bedroom. Picture quality is very good. I won it for £10!

[CapLeaker]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Did you try matching something up at digikey, mouser etc?

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

I failed to check eBay. There are a wealth of transistors there, so I think I'll order from there.

Four FETs plus one gate driver and transistor pair bad, pretty easy fix if that's all.

[CapLeaker]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

amazon, ali etc have them too

[tw2005]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

you could always try those Fairchilds I subbed in my 50U30, RS UK would have them. TV's been screaming along nicely since Dec 14, no complaints from the old fella. Smaller , cost about $1 each here

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Fixed. Just four 30F131s, total cost was £8 to fix.
I might see if I can switch the main board to drive the panel as if it is an GT30 panel (i.e. 3D with high brightness.) I'll have to add heatsinks to the IGBTs, but it may be possible. It's not as bright as I'd like.

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Funny, this set has 7,900 hours. The last one I fixed had 8,000 hours. Wonder if there's a common failure that occurs at this point?

[tw2005]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

It would be nice if al SC/SN were just as easy. Imagine the profit you could make turning these around. Pretty sure the 50U30 I have was close to 8000Hrs

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Yea. Although, I've had good luck recently with easy repairs. None too difficult.

Quick video on Vsus limiting while I have this set open (I did this before power on, so I could be sure transistors were ok)
https://www.youtube.com/watch?v=ROYH...ature=youtu.be

[tw2005]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Yea. Although, I've had good luck recently with easy repairs. None too difficult.

Quick video on Vsus limiting while I have this set open (I did this before power on, so I could be sure transistors were ok)
https://www.youtube.com/watch?v=ROYH...ature=youtu.be

Nice, what's the other one, Samsung LCD?

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Nice, what's the other one, Samsung LCD?

Samsung LED, Smart, 2012 model. My brother's. Figured out the fault - video coming soon.

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

I added a fan to this set. The SN board runs kind of hot so I ran a fan from the 15V supply via an 82 ohm resistor. It spins quite fast (makes too much noise imho) so I may increase the resistor size.

[CapLeaker]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

I added a fan to this set. The SN board runs kind of hot so I ran a fan from the 15V supply via an 82 ohm resistor. It spins quite fast (makes too much noise imho) so I may increase the resistor size.

... or use one of these cheap Chinese DC to DC converters.

[tom66]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

... or use one of these cheap Chinese DC to DC converters.

Resistor is easier
Since a DC fan draws an approximately constant current over its operating range, a fixed resistor can be used.
The fan I used is rated at 37mA 12VDC. I have a 15.5VDC source, so my 82 ohm resistor drops 3.03V giving about 12.5V at the fan.

[retiredcaps]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

I failed to check eBay.

I did see that on ebay, but wasn't sure about authenticity of the components so I stayed quiet. Glad you got it working though.

[retiredcaps]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

amazon, ali etc have them too

I'm going to try my first order with aliexpress sometime this week. I'm working on a TV where I identified the bad parts, but digikey, mouser, etc doesn't stock it.

Item is on ebay, but close to $12 CDN + free ship. Found the same item on aliexpress for $2.70 CDN + free shipping.

I think I will shop for more items on aliexpress vs ebay in the future. If aliexpress turns out to be a positive experience, I think ebay + paypal have some serious competition on their hands. It doesn't help that the CDN $$$ is so low as well.

[CapLeaker]

Re: Panasonic TX-P42U30B shorted SN board (green flash/SOS7)

Yeah... I have pretty good luck with aliexpress... O.k, not everything is perfect and you will get burnt at some point, but for the most part it is actually half decent. I have been using ali for about a year and a half now and took down my ebay / paypal account.