Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
Thanks. I'll look into this as well.
pilotguy251
Member
Last Activity: 07-23-2019, 09:18 AM
Joined: 05-09-2015
Location: Cleveland
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Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
Thanks for the replies. When the set comes on and times out to Standby mode as mentioned above, there is a steady 4.45 volts on the 5V leads of the PS. I disconnected the mainboard from the PS as suggested in another thread and it doesn't seem that the mainboard is dragging down the power supply, so I will study the service manual diagrams and proceed from there. Thanks again.Leave a comment:
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Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
Finally caught the set while it was on and tested the leads on CN 902. Inverter on/off and bright control both read 3.6V. The two 12V leads did read 12V. The two 24V leads did read 24V. Nothing read on any of the grounds. Power on/off read 1.6V, and 5V on the bottom 5V lead. I will allow the set to go into standby and test these leads then, as I mistakenly tested CN 905 the first time in standby....Leave a comment:
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Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
OK, the set eventually came on, but I was out of the house when that happened. Did catch it in standby mode though. The only two leads reading something while the set is in standby are the "inverter on/off" and "bright control". With the multimeter set to the 20V setting, "inverter on/off" reads 0.14 while "bright control" reads 0.12. Could be possible that I wasn't making a good connection with the other leads, but I did them all the same way, so that shouldn't be an...Leave a comment:
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Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
Thanks for your response. First time doing board work, but the ones I replaced seem to be on snugly and have a good connection with no shorting. uF values are the same as the old ones on each new cap. I'll have to wait until the set decides to come up again to do the voltage test. Hopefully that won't be too long, but I will report back at that time.Leave a comment:
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Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
I have an old Sharp LC-42SB45U set that went out in late April of 2019. In reading other threads here on the forum about this specific set, I decided to go ahead and replace a majority of the capacitors on both the PSU and Control boards. When plugged in, the red standby light does not come on, however, the set will power on randomly after a few hours, and stay on until it times out if not powered down intentionally.
Following the time out, the set will not power back on unless it is unplugged for a few hours, then plugged back up, only powering on when it gets ready, and not responding... -
Re: LG 42PJ350-UB won't power on all the way?
For the few seconds that the TV stays "on" yes. They both peak at what the sticker indicates. 60v and 205v.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Ok thank you. I'm going to inspect all the boards further to make sure nothing is swollen and needs to be replaced.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Well, I guess there's no hope for it. Time to start parting it out.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Wow, that's interesting. Didn't see that at first. Well it looks as if they want to reach those, some do, but it clicks back off before the voltages stabilize.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
110v through the VZ, 293v through the VSC, and still hunting for the -VyLeave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Are those on the power supply board? Don't see any of them labeled that just yet.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
VS peaking at 186v for the short time that it comes up and the VC is at around 60v. Nothing on the grounds, NC 180v and M5 V 5vLeave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Hope this helps...Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Yeah, upon testing the voltages for the short time that it comes up, they go up to about 180 on the leads before it goes down.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
That's what it did at first, now it just clicks right back off after a few seconds with the new board in, even if it's disconnected.Leave a comment:
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Re: LG 42PJ350-UB won't power on all the way?
Well, they do light up, and before I got the new mainboard, I could power up the set and the backlight would stay on until I unplugged it.Leave a comment:
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LG 42PJ350-UB won't power on all the way?
I am troubleshooting my LG 42PJ350-UB, and it will not power on. I purchased a new Power supply for it about a month ago, and then a new main board earlier this week. Upon putting in the new parts, I get something I wasn't before, but it still won't power on fully. The relays click, the screen lights up for about a second, then the relays click again, along with a green LED on the logic board, and the set goes back off. And as long as the TV is plugged in, the cycle continues. About five or so seconds between off and partway on. What's going on here and is there any way that I might be able to... -
Re: Possible LG 42PJ350 Main Board Problem?
Yep. Test pattern. Sigh... Spend $40.00 on a new power supply board, thinking that was the problem. Wish I had joined this forum earlier. Thanks for the help though!Last edited by pilotguy251; 05-09-2015, 06:46 PM.Leave a comment:
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Possible LG 42PJ350 Main Board Problem?
Hello, I recently had a shortage/surge in my house due to a screw that scrapped off the rubber coating, and the electricity was grounding back into the stove. So if anything metal touched the surface of the stove, and connected the two burners, there was a huge ball of plasma that would form, and melt whatever piece of metal that was completing the circuit. That issue has been fixed, but it left me with a blown out TV. I took the back panel off, tested voltages all over the place, they all looked good, but I got another power supply board just to make sure. That board came in today, but the problem...
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