Re: Samsung SyncMaster 204T
Any ideas?
IRShifty
Senior Member
Last Activity: 07-11-2013, 10:23 PM
Joined: 05-02-2009
Location: Nor-Cal
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Samsung SyncMaster 204T
Hey guys I'm having trouble with this one. I received the unit having been repaired by someone else in the past. The current issue is when you apply power to the device the power LED comes on but the back-lights don't and the unit is unresponsive, you can not turn the unit off without cutting the power to it.
The power board has 7 caps: 3x330uf 25v, 1x47uf 50v, 2x820uf 25v, 1x180uf 450v.
When I opened the unit the 3x330uf caps were all swollen and the rest looked fine. I replaced all of the caps except the 180uf 250v on the board with panasonics and nichicons from digikey.... -
Re: LG 42LB1DR No Video or Sound
Hey so I just got the TV working. I purchased 2 MOSFETS to replace the 8pin ones on in the specified area. Replacing these MOSFETS was a pain because even after i melted the solder with my heat gun the MOSFETS would not come off easy because they were held on with some type of adhesive as well. I was able to replace one and while replacing the other i became extremely frustrated and a handful of the CAPS i replaced started falling out do to the lower rosin-core solder becoming fluid. I stopped and did not replace the other MOSFET or the CAPS that...Leave a comment:
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Re: LG 42LB1DR No Video or Sound
I did not replace the MOSFETs. Do you recommend purchasing a board like that before replacing the MOSFETs?Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Received the IC today from Digikey. Install went good. Same no display issue, still has a delay on turning off/on. Took some measurements on the 3.4v lines and they are all now showing 2.2v. Where to now? ThanksLeave a comment:
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Re: LG 42LB1DR No Video or Sound
Okay cool. I'm having a hard time finding those MOSFETs, they read 4410n over AA60B. Closest I can find is [url]http://www.ebay.com/itm/5PCs-AO4410-AO-4410-N-Channel-MOSFET-Transistor-/220934080474?pt=LH_DefaultDomain_0&hash=item3370b287da[/url] Can you let me know if you think this part will work or if you can locate a better location to purchase them. ThanksRe: LG 42LB1DR No Video or Sound<br ...70b287da[/url]Leave a comment:
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Re: LG 42LB1DR No Video or Sound
I actually meant D202, and which MOSFETs are 8 pin? I'm not seeing them. ThanksLeave a comment:
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Re: LG 42LB1DR No Video or Sound
Okay well lets do it and see. Which MOSFET's do you suggest replacing? U202?Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Measurements on the 3037 chip:
Fb - 0.67
Vcc - 4.11
LDrv - "-0.02"
Gnd - "-0.02"
SS/SD - 0.05
Comp - 0.03
Vc - 3.56
HDrv - 0.02
Refer to the attachment diagram for the PIN layout.
I also was able to check the voltage in the area you specified earlier. I attached the image again for reference. The area read 5v....Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Okay thanks for the info. I really appreciate your assistance. Digikey definitely looks like the way to go on the controller. I should be able to take those measurements. Wont be easy but with some special placement I think it is possible. I will take them in 20hours from the time of this post if I have the time....Leave a comment:
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Re: LG 42LB1DR No Video or Sound
I receive 1.8v on that copper fin and the one above it. The one to the right reads 5v. part# on U214 is 3037CS. Thanks...Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Both inductors read zero ohms. The only thing in that voltage area on the top side is a capacitor and I can not test the + on the capacitor with it in the circuit. Would it be a sufficient measurement to remove the capacitor and then power the unit on and test the + on the board? Thanks
BTW all 3.4 are back to reading 1.8...Last edited by IRShifty; 03-10-2012, 04:16 PM.Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Any ideas on what to check next?Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Not sure how i should test those spots on the board. The board is reading 1.9v all over that area but it is not being signaled as on. For the PSU to be hooked up to the main board and get the ON signal it has to be mounted on the chassis so I can not test the under side of the board. How should I test for short circuit? After some fiddling and testing everything is hooked up the same as the last test and all 3.4v except the blue 3.4v which is ON/OFF are now reading 1.25v. Super weird. When the Green connector is removed from the PSU...Last edited by IRShifty; 03-06-2012, 12:37 AM.Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Okay, the T-CON board is what I just replaced then. I ordered one from ebay that was pulled from a known working unit. I do not see anything using a flashlight either but it is hard to tell when I cant tell which input it is trying to read from and I do not know where the normal OSD is because I have never seen this model when it is working....Leave a comment:
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Re: LG 42LB1DR No Video or Sound
I also read that the hard drive can cause issues. With the HDD unplugged it still does not power on properly. I have attached a picture of the underside and a scan of it. The scan is missing a tad on the edges so use the picture to see the edges if needed. Note the notch in the corner of the board where the HDD mounting screw is located for direction.Thank you.
That's exactly what i was thinking and that is why i was surprised when there was so much web chatter about it being bad caps on the PSU. I have...Leave a comment:
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Re: LG 42LB1DR No Video or Sound
Your fast, was just documenting those. Added two images to the OP. One has another picture of the PSU, the dots on the connectors are the key for the image with the chart of voltages on it. The top line on the each table in the chart represents the marks on the board and the second row is the voltages i received while testing. The top two connectors read the same, each one goes to one of the back light inverter boards (if that's the correct term).Leave a comment:
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LG 42LB1DR No Video or Sound
Hey guys, I picked up a LG 42LB1DR thinking this would be an easy fix. Its turning out to be a bit more difficult. I'm hoping you experts can shed some light on this repair for me. Basically everything I can find online about this specific model and issue states that it is directly related to some bad caps on the PSU. No problem, I crack it open, see that some of those known bad caps have already been replaced but there is still one on there. I decide to replace almost all of the caps on the board instead of just that one. This includes the ones that were already replaced because I have no idea...Last edited by IRShifty; 03-04-2012, 03:39 PM. -
Re: Samsung SyncMaster 2220WM colored vertical lines
Alright thanks man....Leave a comment:
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Re: Samsung SyncMaster 2220WM colored vertical lines
Is this what you are referring to? if so the lines seem to go through it. Does this indicate an LCD screen problem or a Logical board problem? If this is an LCD issue, would the only way to fix it be to replace the entire LCD screen?...Leave a comment:
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