angelos
Badcaps Veteran
Last Activity: 02-27-2025, 01:54 AM
Joined: 12-04-2012
Location: Free State
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That's right what William1967 says. Sometimes you need to clean the LVDS cable on both ends as well as the connectors. I use benzene.... -
Samsung has had a lot of crap panels that short out in the last few years, models like the TU, KU etc.
Almost every 4th Samsung coming in is having a panel problem....Leave a comment:
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Just an update, So I took your advice KYBOSH and I did not use the Variac. I instead opted to use a couple of incandescent light bulbs in series with the mains fuse to see what the current draw is initially and it seemed fine.
The tv works fine, thanks for your help.
Quite few parts replaced in this Sony KLV-32T400A power supply, Most damage was done to the PFC circuit.
I have added the pictures or your interest.
Regards
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"20241130_1105...Leave a comment:
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I know that SMPS power supplies don't like a low AC input as they can draw a lot of current at startup. But what else can i do? Just give 230V AC and hope for the best?
🔥🔥🔥🔥🔥Leave a comment:
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Hi KYBOSH,
How am i doing it wrong?
There are no schematics on this model. Sony made sure of it.
I have a 500VA isolation transformer for my protection and as for the power supply, it was blown up to begin with.
I simply need to understand the basics of how you ramp up the ac input on the switch mode power supply.
The PFC circuit was damaged. This included the mosfet, driver ic and a few smd components in between.
This power supply is avaialble on ebay or aliexpress as a second hand but they are mad with their price. I have all the time to fix it but i only...Leave a comment:
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Variac Transformers and switch mode power supplies.
Hello everyone,
I was wondering if anyone in the forum can tell me how they use the variac transformer to check a switch mode power supply that they had just repaired.
I wanted to know how they adjust the votlage, do they start from zero and turn it up slowly or rather switch on that about 60V ac ( My country we use 220V ac) and hope for the best.
Also what sounds the PSU should make, what sounds wrong etc. Also if i have a scope what can i check for.
The reason why i am asking is i have a Sony LED TV PSU whose PFC circuit shorted out and upon closer inspection a... -
Hi Lotas, thanks for your reply. I have added board voltages for you to check but according to the service manual they are all 100%
I think you are right, moisture has probably corroded the BGA solder under the logic board. Unless you have something else to add I think i am stuck. No logic board available.
Thanks for your help.
Angelos...Leave a comment:
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Anybody there have experience or can advise me to what to look for?Leave a comment:
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LG Plasma TV Model 50PN4500-TA
Hi Guys, I desperately need your advice on this set.
When pressing standby to "ON" then the Panel has a pre charge flash and further no image. The audio works 100%. I have the TV plugged into HDMI input.
I measured all the main board voltages and they are all correct according to service manual. I then went to the logic board and put a wire on the "Auto" to generate
its own test patterns. This works, telling me that the plasma panels are ok. After removing the jumper we go to having a black image.
I cleaned the ribbon from the main to the logic board,... -
Thank you Lotas for your response. Now i know why technicians are reluctant to repair plasma's. They are a real pain in the ass.
I ordered some other GT30F124 from one of our more reputable suppliers. Maybe it is old stock and original.
Tell me, the original GT30F124 does it come with bent legs or are they straight?Leave a comment:
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Equivalent for GT30F124
Hi guys,
A few days ago i asked a real hard question regarding plasma tv's but nobody could respond. I need to ask if anyone has replaced this IGBT with another type that actually worked.
The industry is awash with fake chinese knock offs.
I am so frustrated.
Kind Regards
A Anagnostou -
Hello Siebiemofokeng,
you said that you installed 30J127 IGBT's, where did you find them?
Regards...Leave a comment:
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There was a +15V rail that measured 18.2V somewhere there.Leave a comment:
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I just don't know where to measure Vscan and what to use as ground reference. Is chassis ground ok?
Vy is ok, Vs and Va is according to panel sticker, some other voltages on Y-SUS also ok according to panel sticker. I think it was a 200V and a 120V. I am at home now so i am recalling from memory. I do have an oscilloscope but don't know what to measure.
on Y-SUS +5VF and +15VF measure weird with chassis ground as reference. its not 5V and 15V.
I suspect something is wrong on this board, not sure.
I did take oscillogram images of the waveform on the buffer board and it...Leave a comment:
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Some pictures of the problem
The white raster is gray and it has the color bars of the previous image...Leave a comment:
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[ATTACH=JSON]{"data-align":"none","data-size":"small","data-attachmentid":3264935}[/ATTACH] Close ups of boards...
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This is the board layout....
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LG 42" Plasma Display Model 42PT350R
Hello Guys,
I am not familiar at all with plasma tv's but i tried my luck anyway since business is so bad. We gotta try, right?
Anyway, the original problem was a tv clicking and not starting due to a short circuit on the Z-Sustain board (on the right side from the rear).
I found two transistors shorted (30F123) and changed the gate driver ic's as well. I think they were FAN73711. I soldered for dry joint on power supply, Y-Sustain and Z-sustain. Started up the TV and the short was gone so i had an image but.....
Lots of colorful speckles on the image and also there... -
Just an update, but replacing the main board on this Dell is as simple as plug n play. No funny tricks to get it to work....
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Looks like nobody likes me. thanks for nothing....Leave a comment:
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