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Old 02-24-2020, 01:54 PM   #1
Lydia
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Default Common LG TV Issue - Antenna Grayed Out

I have been trying to sort this one for ages - i finally removed the main board from the tv today 50LGPK590 and opened up the tuner and re-soldered the main coax connection input but still no joy.

I was talking with a computer engineer at work and he tells me that a lot of LG plasmas have this problem and it might be due to the firmware and as it wont be updated there is nothing you can do?

I find this quite interesting - how would the firmware which hasnt been updated suddenly stop the tv from detecting it has an aerial connected and gray out the Antenna option in the menu - is this something to do with freeview frequency changes?

Thank you in advance

Lydia
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Old 02-24-2020, 02:51 PM   #2
vinceroger69
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Default Re: Common LG TV Issue - Antenna Grayed Out

could this set be stuck in hotel mode would this grey out the antenna settings im not sure have you tried doing a factory reset on this tv
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Old 02-24-2020, 06:00 PM   #3
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Yes thats the first thing i did.
I have two tv aerials so swapped them over to obviate the aerial and coax - no fix.

This problem is all over google if you search for it but no one not even LG can give a solution but it started in happening to old LG tellies on 2017 so maybe it is a firmware issue as all the apps on the tv stopped working then as well.
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Old 02-24-2020, 06:28 PM   #4
budwich
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Default Re: Common LG TV Issue - Antenna Grayed Out

what model are you referring / talking about???? ooops... I see it in the first post... sorry.


OK... with the tv unplugged, get a meter and measure the resistance on the input connector (coax input).... what do you get?

Last edited by budwich; 02-24-2020 at 07:27 PM..
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Old 02-25-2020, 06:43 PM   #5
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Will open the tv and test it and get back thanks Mr Bud¬
Or do you mean measure the resistance between centre core and outer can (earth) to check if its shorted?
>;o)

Last edited by Lydia; 02-25-2020 at 06:47 PM..
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Old 02-25-2020, 07:04 PM   #6
R_J
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Default Re: Common LG TV Issue - Antenna Grayed Out

The r.f. input is going to check like a short because there is likely an input transformer. The problem could be in the service setup.

When you say the "antenna" is greyed out do you mean the Dish icon under setup? or do you mean in the INPUT list?
Could it be "blocked" as in external input blocking

Last edited by R_J; 02-25-2020 at 07:42 PM..
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Old 02-26-2020, 11:59 AM   #7
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Default Re: Common LG TV Issue - Antenna Grayed Out

Quote:
Originally Posted by Lydia View Post
Will open the tv and test it and get back thanks Mr Bud¬
Or do you mean measure the resistance between centre core and outer can (earth) to check if its shorted?
>;o)
I don't know what it will read... you tell us what you get. "obvious issues" may show (totally open or otherwise). Further post a picture of the screen that show what you are referring to in the menu so we (who don't have / haven't seen your set) can understand what you are referring to. Potentially, show a screen just before that screen to provide the forum with a bit of the menu path.
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Old 02-26-2020, 12:20 PM   #8
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Default Re: Common LG TV Issue - Antenna Grayed Out

I rechecked a number of R.F. inputs and most checked shorted, except a newer Toshiba, Its R.F. input checked open (even on 20meg scale).
This is between the center pin and outer threads.

Last edited by R_J; 02-26-2020 at 12:21 PM..
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Old 02-26-2020, 12:26 PM   #9
petehall347
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Default Re: Common LG TV Issue - Antenna Grayed Out

263 page manual here just in case https://manualsbrain.com/en/manuals/1474508/
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Old 02-28-2020, 11:34 AM   #10
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Yes it is the input screen - Aerial icon greyed out and you cannot select it.
However you can go into the setup screen and do an auto tuning which ends up with a screen saying Not Programmed.
Checked the resistance its open - here are a few photos.
I already soldered the centre connector because I saw a really talented guy called MrReeceyburger123 on youtube fix his that way.

I have fixed the tv already perhaps i should add this - the power board failed requiring replacing the common resistor fault.
Then i got the red haze of doom so i bought a new Ysus board and that fixed it but it has started to go red haze again after a few months use on power up (you can actually see it on picture 3) but it usually disappears after a few minutes - tested all the caps on the ysus as i thought this might be the issue but they are all good.
I doubt any of that would cause this issue though!

Sorry if I am not giving much information but I am just learning electronics especially television side of things.
I am a female, blonde but not an airhead just trying to keep my old television alive as I have lemonade pockets!!!

Thank you all for being so kind, it is a very impressive forum so much knowledge and clever people it can be quite intimidating for us beginners!
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Old 02-28-2020, 11:42 AM   #11
R_J
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Default Re: Common LG TV Issue - Antenna Grayed Out

So you had this problem before you soldered the center conductor? Did you remove the tuner module from the main board to do this?
Your first picture is too blurry to make out anything.
If the tuner can't find any channels during a scan, the "antenna" likely won't show up as an input.
There might be voltage values marked for the tuner module pins on the board next to the module.
If this is the correct tuner number, this might help
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Last edited by R_J; 02-28-2020 at 12:30 PM..
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Old 02-28-2020, 11:51 AM   #12
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Default Re: Common LG TV Issue - Antenna Grayed Out

lots of good work.... you need to follow your "nose"... meter... :-)

It is likely that seeing the "open" on the coax input is NOT good. Look closely at the connector. See if you can locate the trace on the board that is connected to the center conductor of the connector. Place the probe as you have shown on the center conductor of the connector and the other at the trace.... you should see a "short" / continuity. Go from there. One note, you may need to use a coax cable (a known good one) to properly access the center conductor / pin as the connector connnection internally may not actually be available to your probe easily / readily and hence might be the reason that you are seeing the open (ie. poor access).
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Old 02-28-2020, 12:10 PM   #13
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Thanks Mr Bud i will need to remove the board i think and i will follow my nose!
>;o)

From what you are saying you mean that constant wiggling and pulling in and out of the aerial connection may have caused the centre pin connection to come loose from the solder which attaches it to the back of the circuit is that what you are saying?
I do agree as the aerial connection was always very tight and removing the cable was always a pain of wiggling and pulling to get it out so I think it is a PEBKAC cascading blonde fault moment lol

I wont tell you what else i did for fear of scaring you!

Mr Reeceyburger123 had the same issue i only soldered it from above i know i should have taken the board out but i am scared in case i cause another problem lol

Blonde moment im afraid I know i should be brave but they dont call me Lydia-disaster for nothing lol!

The tuner module is not removeable it is hard soldered to the board i did take the rf protection metal top off though to see if there were any tell tale burn or damage signs
No service manual!
Yes it was on the bum before i soldered it!

The antenna icon shows up when an aerial is connected you dont need to do a scan so the tv must detect the coax present

I have borrowed an LG 3D monitor tv combo now connected to the same aerial at the mo and the aerial icon is there so i think that might rule out the firmware idea so i think it is a hardware problem now!

Last edited by Lydia; 02-28-2020 at 12:18 PM..
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Old 02-28-2020, 12:19 PM   #14
budwich
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Default Re: Common LG TV Issue - Antenna Grayed Out

my "explanation" wasn't very good. Basically, as part of electrical testing, you try to confirm as much about the electrical path as you can (especially with out an available schematic to follow). Your initial test only tells you that there is NO path between the center conductor to the "sheath" pin that you touched with the other probe. BUT that is trying to test the "entire path" all the way back to the tuner and "back again" to the sheath. However, you don't actually know that your probe is contacting the middle of the connector properly. You can check this by doing the same test as you did but instead touch the other probe to the exposed pin. This will tell you if you have a connection from the center pin of the connector (where the coax cable goes in) to the exposed / soldered external pin. Go from there. Further you can do your same test "looking" towards the tuner by putting the probe on the external pin (that is supposed to be the center) and the other one you used for the shealth / ground. This measurement should "see" what is in the board / tuner and should measure something.

Last edited by budwich; 02-28-2020 at 12:29 PM..
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Old 02-28-2020, 12:32 PM   #15
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Ok so i need to take the board out - this is going to be scary Mr Bud and with my luck its tv disaster time
I think i will leave it till tomorrow Abandoned Engineering and The Walking Dead are on tonight and I cannot miss them haha

Many thanks for putting up with my beginners questions and yes i did already understand about testing full circuit connectivity I see what you mean anyway its really a board removal requirement - Oh dear¬

New telly it is then when i mess this up tomorrow lol - what would you recommend Mr Bud?

I am looking at one of those nice TCL 65 inch Led tv's what is your expert opinion on TCL?

And thank you too Mr RJ must not let you feel left out - your tuner attachment is apprecaited i will use it tomorrow to check voltage - even though i am not sure what any of them do lol

Last edited by Lydia; 02-28-2020 at 12:53 PM..
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Old 02-28-2020, 12:42 PM   #16
R_J
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Default Re: Common LG TV Issue - Antenna Grayed Out

If the R.F connector was not loose or the shield part was not detached from the tuner module, it is very unlikely the center pin was broken.
Check that you have the basic voltages going to the module

Last edited by R_J; 02-28-2020 at 12:45 PM..
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Old 02-28-2020, 12:45 PM   #17
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

I see what you mean because the rf connector and pin basically secure it to the board so it will maybe be a diode or something?
Howver in Mrrecceyburgers video neither was his it is basically the exact same fault!

There must be some sort of damage as the other LG tv aerial icon still shows on screen even if you remove the tv aerial!

Last edited by Lydia; 02-28-2020 at 12:49 PM..
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Old 02-28-2020, 12:53 PM   #18
budwich
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Default Re: Common LG TV Issue - Antenna Grayed Out

you don't need to take the board out at this point. You just need to do the suggested test. Depending on the results, you can then decide on what is the next step.
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Old 02-28-2020, 01:02 PM   #19
R_J
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Default Re: Common LG TV Issue - Antenna Grayed Out

Do you have something that outputs an RF signal? vcr, rf modulator etc. If you do connect that and try a scan, the rf signal from a vcr etc could be a bit stronger and it might show up in the scan.
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Old 02-28-2020, 01:21 PM   #20
Lydia
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Default Re: Common LG TV Issue - Antenna Grayed Out

Problem is there is no exposed pin its on the other side of the board and no way to touch it without taking the board out!

Thanks Mr RJ I have two youview boxes with built in RF Tuners a DN370T and a DN372T also tried with my Tivo-500 and my Tivo-6 and nothing!

The thing is I just switched on the other LG tv and the aerial icon is there even without any aerial being inserted into the rf input!

I do have my old Akai VS-F600 in my av rack so will maybe try that as well now you mention her she hasnt played a tape in years!
>;o)

Last edited by Lydia; 02-28-2020 at 01:25 PM..
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