Re: LG 42LG50FD-AD Intermittent NoGo
Well all seems good. The tv has been testing for a couple of days now and is yet to falter again. Thanks to everyone who offered help.
Cheers
Con
con244
Member
Last Activity: 01-02-2017, 01:25 AM
Joined: 02-16-2013
Location: Unley South Australia
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Re: LG 42LG50FD-AD Intermittent NoGo
Tried cadimans suggestion. Replaced 2 x 3300uf10 caps. There was an improvement so shotgunned the rest of the nearbycaps on the board. The 3 x 2200uf25 were soldered into the board via some metal sleeves. I seem to remember these things being a problem on some of the audio gear I used to fix so soldered the legs to the pads as well as the sleeves. Seems to be working ok now. Will soak test for longer time and see how it pans out.
ConLeave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Sorry I was a little confused myself. It's been a while since I've had my nose in any circuitry. The way it stands now is, there is standby power at powerup and startup power at turn on. I feel like the problem is on the PS board. It is caused by heat because it starts ok when the set is cold. Just need to narrow it down some more. I will get some freezer spray tomorrow. But I will keep fiddling with it til then.
Thanks
Con...Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Budm I think it's the opposite problem it works when it's cold and doesn't when it's warmed up. I have found that if I turn it off when it's warmed up it won't start again until I leave it unpowered for at least 45mins. Maybe I should invest in some freezer spray?
ConLeave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Thanks Glitcher and cadiman. Nothing to lose as far as I am concerned. It's Sunday here, I will pick up some 3300uF10V caps tomorrow and see how they go.
Con
Cadiman
I could only find 2 x 2200uF 10V caps would they be the ones?Last edited by con244; 04-06-2013, 09:15 PM.Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
OK here we go with the regulators from the main board:
IC903
AZ1085S-ADJEI
827J84
SET WORKING
PIN 1 0.02
PIN 2 1.27
PIN 3 3.28
SET NOT WORKING
PIN 1 0.02
PIN 2 1.27
PIN 3 3.28
IC904
AZ1085S-3.3EI
802K06
SET WORKING
PIN 1 0.0
PIN 2 3.30
PIN 3 5.07
SET NOT WORKING
PIN 1 0.0
PIN 2 3.30
PIN 3 5.07
IC905
AZ1117D-3.3EI
830N99
SET WORKING
PIN 1 0.0...Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Will check the voltage regulators. I will check them when the set is working and when it is not to get comparative results.Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Sorry about that blurry pic hopefully either of these will be better! Do you need the other side as well?...Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Hi I left the set unplugged over night. I plugged it in and checked for 5V standby and it was there. Then I checked for the 4V start up (actually 4.45V) voltage after pushing the on button and it was there as well. The tv started with no issue. I left it running for about 20 minutes and turned it off. Tried to turn it back on after 1 minute- no go. The stand by and startup voltages were both there 5V and 4.45V respectively. I tried to find any bad joints and have reworked several suspect ones. I feel like this is a going bad component that is...Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
I think I wasn't clear with my last post. When the button was pressed the 4v came up and when the tv was turned off the 4v disappeared. Whenever I tried to turn the tv on after that there was no 4v. After leaving it for a while the 4v would come back when the button was pushed. I did read your post, perhaps I'll read it again, I do appreciate the help you are giving me,
Thanks
ConLeave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
Thanks for your reply budm, after leaving it for a short while I measured 4V on the pin that has POWER ON written next to it when pushing the on button. The tv came on, I also measured 12V and 5V where they should be on that connector. I am using the manual that has been posted here. I have reposted it. The connector designation is shown as P1100 on the manual but I think it is P200 on my board. After a while I turned the set off and remeasured the voltages. There was no voltage at the POWER ON pin or the 12V pin. The 5V standby was still there....Leave a comment:
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Re: LG 42LG50FD-AD Intermittent NoGo
I let the set sit for a couple of hours, not powered. On powering up the set came alive. I left it on for about 5 minutes then switched it off at the on/off switch. It would not switch back on. From memory, when I used to repair audio gear, silicon generally fails as the temperature drops and caps fail with heat. Is that right? If so perhaps it is caps after all. Any ideas? Should I just shotgun the seven caps in the secondary side?
ConLeave a comment:
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LG 42LG50FD-AD Intermittent NoGo
Hi I have a LCD tv that works sometimes and doesn't other times. I have attached some pics. When I power the tv up the red stand by light comes on, when I switch the tv on the light flashes 3 times and then the blue on light comes on. Sometimes the screen lights up but more often it just stays off. I have checked for standby 5V and have it at the connector that goes to the large board from the PS at all times even when the tv does not start. No 24V or 12V to be found. When the set did actually power up I checked for all the voltages and all was as it should be. I suspect a bad joint some where...
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