Main Board Repair of a 'junked' LG 42LV5500 TV Reflow Oven
79.7 هزار بار بازدید -
5 سال پیش
-
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The first 3 minutes is about the TV and testing the SMPS & TCON. Discussion of Main board starts at about 3:00
One thing I should have done is to make some wood or plastic standoffs to support the middle of the board so that it stops flexing when the video chip warms up.
One commenter used a $7 PTC heater and set it on the video chip for like 6-8 minutes. It reaches 250c and stays there. After heating, you may want to unplug and wait for it to cool so you dont move the chip. Seem like a possible safe way to heat/reflow the chip.
https://www.ebay.com/itm/Aluminum-PTC...
Similar $15 PTC heater on AMZN https://www.amazon.com/gp/product/B07...
Link to Service Manual
http://goihl.com/42LV5500/lg_42lv5500...
Link to Main Board Schematic (for power supplies)
http://goihl.com/42LV5500/lg_42lv5500...
I was given a 2011 42in LG LED TV that had no picture and no backlight. The remove power button worked and I could hear a click. I tested the Power Supply and it was ok. I tested the LCD panel driver board, called the TCON board, and it was ok. I checked all the power supplies on the main board and they were ok. The main control CPU #IC602 (called the 'MICOM') was receiving commands from the front panel and the IR remote and was turning on the power supply, but it did not send the signal to turn on the LED backlight (INV_CTL) or turn on the local Panel 12V (Q507). I think this was because after the main power was turned on, the MICOM was trying to talk to the video processor IC101, but it was offline and was not communicating. This prevented the MICOM from going any further. I reflowed IC101 (sort of) by using a heatgun to apply heat to the video processor chip under the main board heatsink and that fixed the problem. Note that a hair-dryer will not be hot enough. If you have a really big heat gun, you will need to shield the board with metal so as not to burn the PCB. There are many video's about putting this main board in the oven to reflow the board, but I'm against this..
Here is a video about the oven baking method: Repair An LG Television Motherboard B...
Here is a video about a warped board. Did this happen in the oven? Strangely warped main board from LG 4...
I would actually do some troubleshooting on your power supply and T-Con board before trying something as drastic as the oven on the main board. The oven just barely gets to the melting point of solder. Actually at 385 degrees Fahrenheit it doesn't even melt some solders. and it melts all of the solder on your board which could cause other parts to loosen up and cause more problems. I prefer the local heat method myself. I don't doubt that the board may work after the oven, but it may not be a complete reflow of the solder joints - it may just move the board or chip around a little creating a mechanical connection of the affected joint(s).
Video Chip I reflowed BCM35230KFSBG Ball Grid Array
https://www.ebay.com/itm/1pcs-BCM3523...
LG 42LV5500 No picture, not turning on, no backlight, no sound. Main board
Remote PN AKB72914042
https://www.amazon.com/gp/product/B00...
Motion Remote PN akb73295502
https://www.amazon.com/LG-AKB73295502...
Service Remote PN MKJ39170828
https://www.amazon.com/gp/product/B07...
Weller 6966C 250W Electric Heat Gun https://www.amazon.com/dp/B000ICGMN4/...
Full TV Model 42LV5500-UA.AUSYLJR
Boards inside this Model TV
SMPS PN EAY62169801
TCON comes with panel I think
Main Board PNs
EBR73146501
BCM35230
LA12D/E
EAX63333404(0)
Link to EAY62810801 SMPS Manual (similar PS, but NOT for this model)
http://goihl.com/42LV5500/lg_eay62810...
42LV5500 Support Page
https://www.lg.com/us/support/product...
LG Spec Sheet
https://www.lg.com/us/products/docume...
TV User Manual (I had to add .pdf to the end of the downloaded file)
http://gscs-b2c.lge.com/downloadFile?...
The user manual lists all these models on the front cover, so this procedure may work for other models.
LED LCD TV MODELS
42LV3700
47LV3700
55LV3700
42LV5400
47LV5400
55LV5400
LCD TV MODELS
42LK530
47LK530
55LK530
42LK550
47LK550
PLASMA TV MODELS
50PZ750
60PZ750
50PZ950
60PZ950
50PZ950U
60PZ950U
42LV5500
47LV5500
55LV5500
42LW5600
47LW5600
55LW5600
32LW5700
42LW5700
47LW5700
55LW5700
47LW6500
55LW6500
65LW6500
47LW9800
55LW9800
55LV9500
The first 3 minutes is about the TV and testing the SMPS & TCON. Discussion of Main board starts at about 3:00
One thing I should have done is to make some wood or plastic standoffs to support the middle of the board so that it stops flexing when the video chip warms up.
One commenter used a $7 PTC heater and set it on the video chip for like 6-8 minutes. It reaches 250c and stays there. After heating, you may want to unplug and wait for it to cool so you dont move the chip. Seem like a possible safe way to heat/reflow the chip.
https://www.ebay.com/itm/Aluminum-PTC...
Similar $15 PTC heater on AMZN https://www.amazon.com/gp/product/B07...
Link to Service Manual
http://goihl.com/42LV5500/lg_42lv5500...
Link to Main Board Schematic (for power supplies)
http://goihl.com/42LV5500/lg_42lv5500...
I was given a 2011 42in LG LED TV that had no picture and no backlight. The remove power button worked and I could hear a click. I tested the Power Supply and it was ok. I tested the LCD panel driver board, called the TCON board, and it was ok. I checked all the power supplies on the main board and they were ok. The main control CPU #IC602 (called the 'MICOM') was receiving commands from the front panel and the IR remote and was turning on the power supply, but it did not send the signal to turn on the LED backlight (INV_CTL) or turn on the local Panel 12V (Q507). I think this was because after the main power was turned on, the MICOM was trying to talk to the video processor IC101, but it was offline and was not communicating. This prevented the MICOM from going any further. I reflowed IC101 (sort of) by using a heatgun to apply heat to the video processor chip under the main board heatsink and that fixed the problem. Note that a hair-dryer will not be hot enough. If you have a really big heat gun, you will need to shield the board with metal so as not to burn the PCB. There are many video's about putting this main board in the oven to reflow the board, but I'm against this..
Here is a video about the oven baking method: Repair An LG Television Motherboard B...
Here is a video about a warped board. Did this happen in the oven? Strangely warped main board from LG 4...
I would actually do some troubleshooting on your power supply and T-Con board before trying something as drastic as the oven on the main board. The oven just barely gets to the melting point of solder. Actually at 385 degrees Fahrenheit it doesn't even melt some solders. and it melts all of the solder on your board which could cause other parts to loosen up and cause more problems. I prefer the local heat method myself. I don't doubt that the board may work after the oven, but it may not be a complete reflow of the solder joints - it may just move the board or chip around a little creating a mechanical connection of the affected joint(s).
Video Chip I reflowed BCM35230KFSBG Ball Grid Array
https://www.ebay.com/itm/1pcs-BCM3523...
LG 42LV5500 No picture, not turning on, no backlight, no sound. Main board
Remote PN AKB72914042
https://www.amazon.com/gp/product/B00...
Motion Remote PN akb73295502
https://www.amazon.com/LG-AKB73295502...
Service Remote PN MKJ39170828
https://www.amazon.com/gp/product/B07...
Weller 6966C 250W Electric Heat Gun https://www.amazon.com/dp/B000ICGMN4/...
Full TV Model 42LV5500-UA.AUSYLJR
Boards inside this Model TV
SMPS PN EAY62169801
TCON comes with panel I think
Main Board PNs
EBR73146501
BCM35230
LA12D/E
EAX63333404(0)
Link to EAY62810801 SMPS Manual (similar PS, but NOT for this model)
http://goihl.com/42LV5500/lg_eay62810...
42LV5500 Support Page
https://www.lg.com/us/support/product...
LG Spec Sheet
https://www.lg.com/us/products/docume...
TV User Manual (I had to add .pdf to the end of the downloaded file)
http://gscs-b2c.lge.com/downloadFile?...
The user manual lists all these models on the front cover, so this procedure may work for other models.
LED LCD TV MODELS
42LV3700
47LV3700
55LV3700
42LV5400
47LV5400
55LV5400
LCD TV MODELS
42LK530
47LK530
55LK530
42LK550
47LK550
PLASMA TV MODELS
50PZ750
60PZ750
50PZ950
60PZ950
50PZ950U
60PZ950U
42LV5500
47LV5500
55LV5500
42LW5600
47LW5600
55LW5600
32LW5700
42LW5700
47LW5700
55LW5700
47LW6500
55LW6500
65LW6500
47LW9800
55LW9800
55LV9500
5 سال پیش
در تاریخ 1398/11/27 منتشر شده
است.
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