Re: LG NS-PDP42 SMPS clicks off right after power turned on
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2dbit
Senior Member
Last Activity: 08-30-2020, 02:04 PM
Joined: 05-23-2012
Location: Chicago
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LG NS-PDP42 SMPS clicks off right after power turned on
This tv had a blown Z board, and was replaced. The SMPS went with it.
I changed the SMPS and the current problem is that the power supply turns on for a brief moment, then clicks itself back off.
With the SMPS removed from the TV, I can power it on and it will maintain two 60watt bulbs wires in series across VS.
Wondering at this point if there's an issue with the main board, or if the problem on the z board took out the x board...
The fuses located on the x board are good. -
Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Well, changed all the bits and pieces, powered it on, and for a moment it was nice, two 40watt bulbs glowing, but, that was only for about 5 seconds before there were explosions and a small fire that went out after I finally got it unplugged....Leave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Looks like the diodes survived. Removed and checked good. They're SB140A diodes. Gonna order new ones regardless.Leave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Perhaps for good measure, a new diode... Going to have to unmount the diode so I know what to orderLeave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Nope, there's a Resistor and Diode between gate and IC and on the Source there's a resistor between the FET and IC.Leave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Well, since something is clearly wrong with the power supply, I started ripping things off the board.
I pulled the blue stripped fuse and found it to be open, so I pulled the heat sink containing Q852(W20NK50Z), Q851(same as 852), Q151(P6NK90ZFP), and Q801(same as 151).
Q151 and Q801 both check good.
The two FETs, Q852 and Q851 are both dead shorts across all pins.
Suppose the question is, knowing the two FETs blew, how far is the carnage going to go? Should...Leave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
The two lights connected to the VS barely glow before it shuts downLeave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
The z-sus was bad and has been replaced. Not sure if the new one is good, or if the old one caused harm to the x board, but the SMPS is now on the fritz. The power cycling is occurring with the SMPS removed from the set and being triggered on with 100ohm resistors. The load on the VS bus is two 40watt incandescent bulbs in seriesLeave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
[URL="http://lcd-television-repair.com/newsletter/LG_42PC5DC_Plasma_TV_Switch_Mode_Power_Supply_Operation_and_Troubleshooting.html"]http://lcd-television-repair.com/newsletter/LG_42PC5DC_Plasma_TV_Switch_Mode_Power_Supply_Operation_and_Troubleshooting.html[/URL]
I removed the power supply and followed the guide that is linked at the top of this post.
I found that each step of bringing the SMPS to full operation passed(progressive check of each lower voltage) up until the...Leave a comment:
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Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
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[attach]114927[/attach]Re: Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
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Insignia NS-PDP42 Powersupply not turning on after Zsus chip change
Anyone who's made the attempt to replace the IPM chip on either X or Z boards knows it is a PITA.
Well, I managed to do something horribly wrong while operating on mine, and after replacement the tv turned on for a few seconds (didn't see the screen, it was still face down for smoke check) and clicked right off.
Since then, the power supply will just click on for a few seconds, then click right off.
I knew I did something horrible, and didn't want to risk futher damage, so I ordered a replacement board. Hopefully the problem stayed on that board,... -
Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
Well, unless I am not using proper keywords, I have not found any info regarding the installation of a matched set of later revision buffer boards working or not. I imagine it should be ok, especially with an A4 sustain board in there.Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
Ok, well... I spent some time and frankensteined the TV back together. I was able to isolate the problem down to the logic board. I found a logic board on fleabay cheap enough, but now I'm without buffers.
Hopefully at some point a set of buffers comes around.
The boards in this TV are revision A2. There's no white connector between the two. Does anyone know just how compatible the A4 is with the A2? The A4 has the white connector between the boards... The sustain board is a A4... It's working...Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
Well, what I ended up doing was taking the TV's old Y-Sustain board and both its upper and lower buffers and put them into a Philips that's been laying around dead for quite some time. At least the Philips is up and running now.
Who knows what's up with the Samsung. Logic board perhaps? Either way, it needs upper/lower buffer boards plus whatever is needed to fix the snow issue.Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
I wonder about the logic board, and I suppose it's not unheard of that the discrepancy would exist with or without the test pattern displayed. However, the logic board from the Philips is a Rev A1 while the Samsung has an A2 in it. I know it's not recommended to use mismatching revisions, but for this instance, since it's already in hand, at most I believe it would be my time that is wasted...Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
I had an X-Main board here from a philips... Figured, the discrepancy doesn't match, but if I don't try it, it'll be it. It wasn't. Still no joy.Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
Hm.
Well, I replaced the Y sustain board. Following replacement, prior to installing buffers, I checked all panel voltages. All checked good.
Powered down, installed the buffers and turned the TV back on. No Joy. Problem still exists.
So, problem does not reside with the Y-sustain.Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
The board arrived today. I'll install it, connect the data cable, and the power. I'll leave the buffers out for now and check all voltages. If everything checks out good, I'll put in the buffers. Suppose I should check the waveform as well?...Leave a comment:
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Re: Samsung HP-R5052 snow at top and bottom of screen (pics)
well, no joke...found a board on fleabay for $40... claim is meets or exceeds manufacturer's specs, but I take that with a grain of salt!!! So long as it doesn't blow out the buffers, I'll accept the risk. Once the old board is out, perhaps I'll set it on a table and see if I can't find any bad bits and pieces.Leave a comment:
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