Lightning Strike: 55" TV dead: is display panel OK?

[MrCreosote]

THE LIGHTNING:

This was a very close strike, blew a 15 amp breaker for all ceiling lights in home AND could smell ozone for a few minutes after strike.

Very close and probably a very strong EMP.

THE TV:

No standby LED. Some voltage from PSB (not totally dead).

But found a kit of ALL 4 circuit boards for $55.

At first thought, this will fix my TV.

But then lightning has the ability to totally fry semiconductors. Which would include any or all of the PCBs. However, the display is one big semiconductor and given the extreme closeness of the strike,

What are the chances the display is good?

I can envision the LCD panel becoming an antenna and become the engine that damaged the PCBs.

But I'm just guessing.

[stj]

coils and parts connected to coils are what to check.

[handsworth]

For $55 I would try it. Some Ebay sellers have a no questions asked , 30 day full refund. Saves time. IMO

[Topcat]

No make? no model? No detailed information?

Don't expect too many useful replies...

[MrCreosote]

Originally Posted by Topcat

No make? no model? No detailed information?

Don't expect too many useful replies...

I was trying to get a general sense as to the probability that a display is bad.

It is a Hisense 55H7B and here is the kit:

https://www.shopjimmy.com/search.php...%20parts%20kit

Obviously if the lightning strike is close enough, every single component in the TV will be destroyed.

I'm guessing although the LED standby is not on, the fact that there is 24v on the PSB 18v pins (#9 & #10), the regulators are not working.

If there was a big surge in power supply to the regulators, so much that they were blown open, that big overvoltage may have made it to the main board and done damage.

So I'm thinking there is a good chance both boards are bad.

But there are 2 other boards there that also could be bad and are harder to test.

So I'm thinking the ALL BOARDS kit of 4 for $55 + $10 shipping is a good gamble.

My concern is that the EMP spike was so strong from the strike that it generate enough current in the horizontal ceiling light wiring to trip a 15 amp breaker and take out a ceiling fan motor (coils!) That EMP might have been strong enough to generate currents in the display that would FUBAR it.

There also was a CM4228 8-bay UHF antenna with 20' of cable connected to the TV with a CM's best mast mounted amplifier. While that could have sent a spike through the antenna input, it probably would not have taken out the PSB regulators.

Since the main panel had an external whole home surge protector AND the TV was running through an APC Backups ES 725, I'm thinking the damage was the "OTA" EMP and not a surge coming from the electrical entrance.

[MrCreosote]

Originally Posted by stj

coils and parts connected to coils are what to check.

This sounds like great advice.

Might also explain why the ceiling fan motor is dead too. (could be the little glass thermal overload thingee burried in the windings popped)

[Davi.p]

How much time is passed since you used your multimeter? Try take a surely good battery and test it in volt, i'm not sure of that 24v... Supposing the surge protectors have done its job well, the delicate part prone to fail due to EMI are the memories content, so if psu is goog buy an used mainboard first or try replacing the content of at least 8pins eproms..

[MrCreosote]

Originally Posted by Davi.p

How much time is passed since you used your multimeter? Try take a surely good battery and test it in volt, i'm not sure of that 24v... Supposing the surge protectors have done its job well, the delicate part prone to fail due to EMI are the memories content, so if psu is goog buy an used mainboard first or try replacing the content of at least 8pins eproms..

When I got the 24v on the 18v pins, the first thing I did was try another multimeter. I got the 24v w/board tested on bench and also fully installed in the TV. Something is "off" with that board.

I don't know how to "turn it on" on the bench because it does not have a 5v standby voltage, just 2 12v pins in addition to the 2 18v pins. I would test the 12v if I knew how to jumper it "on" on the bench.

I have a pin callout I will edit in here shortly (I hope.)

I talked to Eaton about my whole house surge protector device and how the lightning strike tripped the 15 amp ceiling light breaker. He agree it was the electromagnetic field of the lightning itself that was "received" by the horizontal wiring (aka "antenna").

Since the TV was connected to an APC UPS and there was a whole house surge box on the main panel, it is unlikely that the surge came through the line cord.

THE $64 QUESTION is did the 55" panel "receive" enough EMP to generate currents in the panel that would damage it. Perhaps even the LED backlight strips? I don't know.

I'm going to buy all 4 boards for the $55 at shopjimmy.com and roll the dice.

[Th3_uN1Qu3]

The panel is a low resistance device. Getting damaged by lightning is unlikely. The motherboard is usually what dies. HDMI switch IC, CPU and tuner. I've fixed lightning damaged sets from the CRT days up to now and I haven't seen a screen go bust.

[Davi.p]

i don't think lightning magnetic field can make current flow on a tv, the magnetic field destroys non volatile memory data.. don't think that 18v is surely correct as tension indication, sometimes doesn't match, i don't know how is the mad that sells 4 boards for 55$ or maybe in the USA tv costs less than half than here.. i think psu is good, mainboard bad.

[MrCreosote]

Originally Posted by Davi.p

i don't think lightning magnetic field can make current flow on a tv, the magnetic field destroys non volatile memory data.. don't think that 18v is surely correct as tension indication, sometimes doesn't match, i don't know how is the mad that sells 4 boards for 55$ or maybe in the USA tv costs less than half than here.. i think psu is good, mainboard bad.

There is no 5v Standby voltage that powers the main board which switches on the PSB via the SW pin. Also, read threads and the two 12v pins and two 18v pins are the ones that are switched on. When plugged in, there should only be the 5v STB voltage - the 12 and 18v should be off - they energize when set is turned on. So 24v on the 18v pins when set merely plugged in is way bad.

This also means there is no way to switch board on when tested on bench since there is no 5v STB present.

The deal is at shopjimmy.com - I can't believe what they have. it's almost endless. I've heard of many sets shipped end up with cracked displays - so where do all the good boards go? He has more complete board kits than I have time to scroll through the listings. It's almost to the point if someone has a 70" that is dead selling for near nothing, might be able to get a kit for anywhere from $45 to $85.

[Davi.p]

I suspect about that 5v, sometimes some users expect that tension to be present but in hinsense tv often i have seen always-on psu with the couple 12v 18v , there's a small transformer that seems for standby psu but is only for insulating high tension part to low tension both in primary side. So post the pinout, we see...

[R_J]

If this is the RSAG7.820.6106, It is an ALWAYS ON power supply that supplies 18 & 12v. These will read high with a no load condition (tv in standby/off). There is no 5 volts standby from this power supply, The STB pin is meant to turn on the PFC section and bring the main supply out of standby mode.
All lower voltages are produced on the main board.

[Th3_uN1Qu3]

So, in conclusion, your power supply is functional or at worst slightly damaged, and all you need to buy as an entire board is a main.

[MrCreosote]

Well, I got all 4 boards for $45 so I went that route.

I was starting to think the Main was the problem but that 24v threw me off as well as no 5v.

So I guess they made a non-regulated "18v" supply which I suppose is OK if the load is constant but how does one now tell if the voltage is out of spec?

Just wondering: how do you switch on the PSB on the bench?

[MrCreosote]

Originally Posted by R_J

If this is the RSAG7.820.6106, It is an ALWAYS ON power supply that supplies 18 & 12v. These will read high with a no load condition (tv in standby/off). There is no 5 volts standby from this power supply, The STB pin is meant to turn on the PFC section and bring the main supply out of standby mode.
All lower voltages are produced on the main board.

Yes it is the RSAG7.820.6106/ROH and there is 0V @ the two 12v pins when plugged in. (and 24V @ the two 18v pins).

I will read all pins on the old PSB and then when I put all the replacement boards in, I'll reread them and compare.

[Davi.p]

Casually i have schematics on my phone, you have to supply 3-5v to SW and STB pins...

[MrCreosote]

TV FIXED: I got the shopjimmy ALL boards kit for $55 shipped. Put the power and main boards in. Fired it up, 3 firmware updates, and it's running just fine.

Now I can wait for 100% ATSC 3.0 adoption and who knows, affordable OLED? (Hisense might try to horn in on the top tier w/cheaper OLEDs - we'll see. But their 100" 4k for $3500 makes me take notice.

[Davi.p]

And the probably good other PSB which end does? Tcon is probably erased like mainboard..