Dear Dannyx
You should borrow an infra-red camera and your board under it to get some clues while using your protective bulb.... For sure, the short will get hot under the thermal cam....
You close to solve this repair.... Keep going on!!!!!!!!
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Dear Sam
The UCx84x mosfet drivers family is frequently used in many psu...... Texas Instruments has even given an application note ( U100-A) where they describe a generic synchronisation ( page 10) with an external timer ( NE555), applicable to many circuits..... I have found this problem of UC3845 not starting up because of a low vcc in several forums and videos with different psu circuitry.
Best regards
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Psu repair: UC3845 not starting up because of NE555 defect
Dear friends from Badcaps
I have been searching for a long time to repair sucessfully a battery charger taking in 230V AC and outputting normally 14V DC. Its power mosfet has been shorted ( Infineon 06N80C3), probably because the bulk storage rectifier capacitor had swollen and had no capacitance anymore and a very high resistance.. The mosfet short has naturaly blown its 0.15 ohms resistor then its driver, the UC3845 IC which was shorted between pins 5 (ground) and 7 (vcc) plus 8 (Vref). Another small resistor surrounding was also dead. So, I have replaced the bulk storage capacitor, the...3 Photos
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Re: 29F2G08ABAEA firmware for SHARP TV
I have found my firmware and I post the google drive link: [url]https://drive.google.com/drive/folders/1XIdqXYbghzJb8dCJuxrhHFLWp0UZrZ21[/url]
I hope this may help someone!!!!!!!!Re: 29F2G08ABAEA firmware for SHARP ...omeone!!!!!!!!Re: 29F2G08ABAEA firmware for SHARP TV
I have found my firmware and I post the google drive link:
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29F2G08ABAEA firmware for SHARP TV
Hi driends!!!
I have a SHARP tv LC-60LE652E with a QPWBXG135WJN2 that has its stand-by light blue on but that does not power on.... I have checked the power board which seems fine. Its seems that the defect comes from the main board....
I would like to flash the nand chip: a 29F2G08ABAEA ic. Has someone its firmware, please?????
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Re: Sharp LC-39LE652V Nand Flash
Dear friend
The google drive link seems dead.... Could you reupload your precious file, please???
...
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Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages
Dear friends from badcaps!!!!
I also have had some troubles with the same Philips 47PFL4606H/12 TV...:: The fault was slightly different: once plugged in, the tv remained dead, with no led lit, until you unplug and reconnect the plug from the mains, sometimes several times.... It was a friend's tv and I did not test it for longer....
I have found that when the tv did not start, the 5V voltage line stayed low, around 4,70V and the 3,3V was missing on the PSU (715G4546-P03-H20-003U)... When the...
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Re: Bios for Asus TP412UA
Hi friend hdd00!!!!
Does my TP412UA bios dump work, please???? Best regards
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Re: Bios for Asus TP412UA
Dear hdd00
I attach the .bin reading of my TP412UA bios... This bin file seems correct through UEFI Tool but my TP412UA is dead: charging light but no reaction to the power button.... I have changed the SIO ITE 8987E chip with no luck... I would appreciate that you give a feedback for bios bin file: does it work on your TP412UA????...
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ASUS TP412UA BIOS Request / Help with UEFI Tool
Hi friends!!!
This is the original bios bin file that I have extracted with my TL866 programmer..... Could someone tell me if this bios works correctly???? On the net, all the bios available are pay for........
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Asus TP412UA charging but DEAD
Hi friends from Badcaps!!!
May I request your advice for the repair of this ASUS TP412UA Rev.3. motherboard. It is a 2,5 years old laptop, a nice Vivobook 14 inches that has felt several times and has stopped suddenly to work. My brother has sent it to Asus Service who has made an invoice of 800 euros to change the motherboard....
The original charger may be responsible for the breakdown as it gives its 19V from time to time and then 0v.... When plugged in a working charger the 19V charges the battery with the charging led lit on and a good 12,2v battery voltage....
BUT,...
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Re: Macbook Air 2015 no backlight
I have a post on Louis Rossmann forum of a guy having the half dim screen after soldering a backlight driver, like me... And like him, I had some problem in the led return lines: ISEN1, ISEN2 and ISEN3 were around 0.58v in diode mode measured at the resistors while ISEN4, ISEN5 and ISEN6 were OL...
I have tried to reflow my LP8550 and ISEN6 is at 0.58V now, while ISEN4 and 5 stays OL despite their balls under LP8550 viewed from the side under the microscope seem to attached..... Probably, my Chinese LP8550 is somehow defective. Maybe the backlight...
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Re: Macbook Air 2015 no backlight
Dear friends!!
Thank you for all your answers....
I have measured the voltage at Q7706: pin3=2,82v and pin4= 8,55v but I had the surprise to measure 19,6v, for the first time after the backlight diode and at pin 3 and 4 of the LVDS connector. I have reassembled the Macbook: the result is better but not good. I get backlight but just on the right half of the screen and this backlight is slightly blincking....
What could it be??? Corroded LVDS connector???
Thanks a lot again for your help
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Re: Macbook Air 2015 no backlight
Hi!!!!
My PPVIN S0SW LCDBKLT FET line shows 8.5v....
I have not measured EDP BKLT EN neither BKLT PLT BST L, because if I get those 8.5V, the mosfets work correctly and it seems that I get no boost which should be LP8550 fault.....
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Re: Macbook Air 2015 no backlight
I have found ARROW, to be an official TI official distributor, with free shipping and I have been able to order 10 original LP8550 for 22 euros, comparated to 14,50 with Ali...
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Re: Macbook Air 2015 no backlight
On Texas Instruments datasheet of the LP8550, the peak solder temperature is mentionned to be 260C, when we solder at 500, 420, 400 or even 280C, we are far above the TI recommendations.........
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Re: Macbook Air 2015 no backlight
Thanks for the advice, Piernov!!! I have a real admiration for your knowledge and all the valuable teachings you give us. Mouser has expensive shipping fees.... Would you advise another real distributor with cheaper shipping????
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Re: Macbook Air 2015 no backlight
HI, friends!!!!
I have reordered 10 new LP8550 IC, from Aliexpress, from a good reputation seller. My 5 first LP8550 have all being soldered without success... I solder with a Quick 861DW hot air station, with a low air blow (at 30) to avoid others components to fly away... At first, I had fixed my temperature at 500°C, as usual, then 420°C, then 280°C, considering that this LP8550 is small and contains a heat sensitive mosfet. I use a *10 magnifying microscope that I have bought 220 euros to my local electronics dealer and which gives...
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Re: Macbook Air 2015 no backlight
Could it be that my LP8550 ICs are defective???? I have changed it again this morning twice, at 280°C, with a very good look of the bga balls soldering under the microscope....
I rechecked the continuity of the SW and FB lines, with voltages of 8.3v of the FB line and 8.5v of the SW line.....
I do not understand what could be the problem...
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Re: Macbook Air 2015 no backlight
R7757 and R7753 have 3.3V on each pins. They are 0 ohms resistors in good continuity on my board...
Thanks for your advices
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