ipad mini backlight Not Working - Page 4 - GSM-Forum

naturalsurfer · 02-14-2014, 01:03

Or if you can tell us diode value approximately to look for it in a electronics shop. Thanks

chryslerdriver · 02-14-2014, 08:38

Good morning,

I've uploaded the picture yet.
Unfortunately I don't know the type of the diode. Afaik is this a special schottky-diode.
You'll find the same in the iPad 1 too. Check the diode by lifting on one side with a professional semiconductor tester. Be careful because not every multimeter can do this.
If the diode is broken, replace it. If not than check the coils (they are normally very durable) and if the're good replace the square-IC near on the left side.

That's all you can do...

The picture shows a water damaged unit which I got from ebay. The owner tried to "repair" it an gave up. Now it works!

http://www.freeimagehosting.net/newuploads/76q5v.jpg

naturalsurfer · 02-14-2014, 12:37

Ok on monday, at shop, I will try (crossing my fingers to be successful), and I will report about. Thanks a lot for information

naturalsurfer · 02-16-2014, 00:10

Hi, I have bought in ebay a repair kit with the "IC repair kit"(diode and filter), and in details there is the following explanation about circuit working way (hope to be right):

iPad backlight circuits is simple, the power goes from the main power regulation chip to the 4R7 Coil(likely to be faulty in water damaged ipad only), then to the Backlight IC( very likely to be faulty in a short), then to the Backlight filter( very likely to be faulty in a short), then to the LCD screen connector holder(unlikely to be faulty unless from physical damage) then to the LCD cable wire (unlikely to be faulty) and finally screen (unlikely to be faulty). the return circuits comes form the screen through 6 small filters in right next to the screen (unlikely to be faulty).

naturalsurfer · 02-16-2014, 02:29

That is the kit i bought, but without 4R7, is this coil for backlight or touch screen? Thanks

terrymarsy · 02-19-2014, 23:51

hi im new to this site but can i say you were a very big help when i replaced my sons ipad2 lcd. i now have a bit of a problem with the screen on my ipad mini i have replaced it for a new one but as a noobish mistake like a lot of others not disconected the battery before disconnecting and reconecting the old and new lcd. the problem i have is that i hard reset the ipad the apple logo comes on for about 5 seconds then the screen goes completely black but the ipad is still on and i can unlock it using the touch screen even tho there is no picture can anybody help as i am not sure weather the fuse coil would cause this problem as the backlight works for 5 seconds thanks

chryslerdriver · 02-20-2014, 00:24

Hello,

I've had that error, but I don't know exactly what it was. Maybe it's just the diode. I don't think that the fuse is broken because the display lit up for seconds.

Unfortunately it's difficult to say exactly what it could be. If you're not familiar with repairing SMD-parts leave it...

Have a good day.

terrymarsy · 02-20-2014, 19:18

thanks ill take your advice and send it off to some1 with more experience

AlgoJerViA · 07-15-2014, 12:48

Hi
I have replaced the digitizer on my nephews iPad Mini (A1432). At first I honored Murphy's law and soldered the digitizer on backwards on the digitizer chip board.

It took me some time to realize what was wrong since Apple uses those wonderful error message in style with error #, do you want to check error # on the internet... error # means that something went wrong. However I resoldered the digitizer and now the home button and touch seems to work but the backlight died. This was before I know that I had to disconnect the battery and LCD in the right order so a current surge is quite likely. However, the backlight did come back for a short period of time (maybe about 30s) at least two times.
I have tested the series of small fuses close to the LCD port and they are all fine. The larger fuse that is the most common failure has a resistance of about 700 Ohms that seems very high for a fuse. But is it even possible that the fuse has been partly burned, that seems very far fetch. Is it another path that cause this resistance and is this the excepted value when the fuse is burned?
Both the 2R2 and the 4R7 have a resistance close to zero. However when I try to measure the diode I get no path in either direction. (I realized that now) So the diode is broken. But what about the fuse?
Also do you have any suggestions how to best remove the EMI base, I have a hot air station if that helps.
Also, there is a voltage drop about 4.x v over the diode, does that seem right?
I have a local electronics store near here so is the characteristics know of the diode so that I can get a compatible replacement part without waiting the delivery?

//AlgoJerViA

chryslerdriver · 07-28-2014, 09:17

Hello and sorry for the late reply

.

Firstly (and I mean normally) the fuse is the main problem.
Secondly the diode is broken (you don't get the diode at a normal electronic distributer, because it's a special one). Most people get the right diode at ebay or from a iCloud locked unit, and resolder it with wrong polatity! After that the backlight still doesn't work.
Thirdly I've never ever had a broken IC, coil or controller.

I can't answer your questions, because I'm on a business-trip and don't have access to my handwritten documents yet.

Change the fuse and with luck the iPad should work again.
Be very careful with the tiny connectors because it's easy to damage small components nearby when re-inserting.
If you've checked everything assemble all shields carefully together and before reseating the touchscreen check if everything works (especially the digitizer).

Soldering the IC to the digitizer is very complicated. I always buy the complete ones with the Hall-Sensor for detecting the original Apple case. There's always a possibility that a small range of the touch won't work because of short-circuit or anything else.

Good luck

z_zba · 03-17-2015, 20:27

nice bro wwwoooowww this is work

capture1990 · 04-13-2015, 22:45

Hi everybody

Hope you can help me. I have here an iPad mini with no backlight. The Diode seems to be ok, the fuse i have replaced but i have still only the battery power at the led output where there should be about 21V.

Do you have any idea? there seems to be a burnt coil (L8229) but it has still connection. Can this be the error?

Thanks for your help!

sqmaniak · 11-05-2015, 11:00

Hi...
I have iPad Mini A1454 with no backlight...
I tried to jumper from component D8228 to C2250 directly and the backlight is on again... but when I made a jumper, I accidentally removed the L47012_WIFI component and now the component is missing...

I turned on the iPad with no L47012_WIFI component and it's still working...

But I cannot try to use the iPad because the digitizer is broken and I have purchased the new digitizer and still in the ship. So I cannot try the WIFI functionality... I fear that WIFI wouldn't work in the future...

Say if the WIFI function wouldn't work when I attach the new digitizer, can I directly make a jumper with solder paste or wire in L47012_WIFI position?

Please help me... Thanks

chryslerdriver · 11-05-2015, 20:50

Hi!
Unfortunately I'm on a business-trip and don't have access to my documents and PCBs. What is the L47012? Is it a coil or a necessary WiFi-IC?

Wait until the Touchscreen arrives. Maybe it still works, now you can't do anything.

Have a great day.

sqmaniak · 11-08-2015, 07:15

it's just a coil with blue color and a dot in it... I've pm you the pict... thx

02-19-2014, 23:51	#51 (permalink)
terrymarsy Junior Member Join Date: Sep 2011 Posts: 2 Member: 1650705 Status: Offline Sonork: terry marsy Thanks Meter: 0	ipad mini lcd + backlight hi im new to this site but can i say you were a very big help when i replaced my sons ipad2 lcd. i now have a bit of a problem with the screen on my ipad mini i have replaced it for a new one but as a noobish mistake like a lot of others not disconected the battery before disconnecting and reconecting the old and new lcd. the problem i have is that i hard reset the ipad the apple logo comes on for about 5 seconds then the screen goes completely black but the ipad is still on and i can unlock it using the touch screen even tho there is no picture can anybody help as i am not sure weather the fuse coil would cause this problem as the backlight works for 5 seconds thanks

04-13-2015, 22:45	#57 (permalink)
capture1990 Junior Member Join Date: Jul 2014 Posts: 5 Member: 2230035 Status: Offline Thanks Meter: 0	still broken backlight Hi everybody Hope you can help me. I have here an iPad mini with no backlight. The Diode seems to be ok, the fuse i have replaced but i have still only the battery power at the led output where there should be about 21V. Do you have any idea? there seems to be a burnt coil (L8229) but it has still connection. Can this be the error? Thanks for your help!

02-14-2014, 01:03	#46 (permalink)
naturalsurfer Freak Poster Join Date: Feb 2005 Location: Spain Age: 41 Posts: 215 Member: 113587 Status: Offline Thanks Meter: 16	Or if you can tell us diode value approximately to look for it in a electronics shop. Thanks

02-14-2014, 08:38	#47 (permalink)
chryslerdriver Insane Poster Join Date: Nov 2012 Location: Austria (Europe) Posts: 61 Member: 1842505 Status: Offline Sonork: 2344 Thanks Meter: 4	Good morning, I've uploaded the picture yet. Unfortunately I don't know the type of the diode. Afaik is this a special schottky-diode. You'll find the same in the iPad 1 too. Check the diode by lifting on one side with a professional semiconductor tester. Be careful because not every multimeter can do this. If the diode is broken, replace it. If not than check the coils (they are normally very durable) and if the're good replace the square-IC near on the left side. That's all you can do... The picture shows a water damaged unit which I got from ebay. The owner tried to "repair" it an gave up. Now it works! http://www.freeimagehosting.net/newuploads/76q5v.jpg

02-14-2014, 12:37	#48 (permalink)
naturalsurfer Freak Poster Join Date: Feb 2005 Location: Spain Age: 41 Posts: 215 Member: 113587 Status: Offline Thanks Meter: 16	Ok on monday, at shop, I will try (crossing my fingers to be successful), and I will report about. Thanks a lot for information

02-16-2014, 00:10	#49 (permalink)
naturalsurfer Freak Poster Join Date: Feb 2005 Location: Spain Age: 41 Posts: 215 Member: 113587 Status: Offline Thanks Meter: 16	Hi, I have bought in ebay a repair kit with the "IC repair kit"(diode and filter), and in details there is the following explanation about circuit working way (hope to be right): iPad backlight circuits is simple, the power goes from the main power regulation chip to the 4R7 Coil(likely to be faulty in water damaged ipad only), then to the Backlight IC( very likely to be faulty in a short), then to the Backlight filter( very likely to be faulty in a short), then to the LCD screen connector holder(unlikely to be faulty unless from physical damage) then to the LCD cable wire (unlikely to be faulty) and finally screen (unlikely to be faulty). the return circuits comes form the screen through 6 small filters in right next to the screen (unlikely to be faulty).

02-16-2014, 02:29	#50 (permalink)
naturalsurfer Freak Poster Join Date: Feb 2005 Location: Spain Age: 41 Posts: 215 Member: 113587 Status: Offline Thanks Meter: 16	That is the kit i bought, but without 4R7, is this coil for backlight or touch screen? Thanks

02-20-2014, 00:24	#52 (permalink)
chryslerdriver Insane Poster Join Date: Nov 2012 Location: Austria (Europe) Posts: 61 Member: 1842505 Status: Offline Sonork: 2344 Thanks Meter: 4	Hello, I've had that error, but I don't know exactly what it was. Maybe it's just the diode. I don't think that the fuse is broken because the display lit up for seconds. Unfortunately it's difficult to say exactly what it could be. If you're not familiar with repairing SMD-parts leave it... Have a good day.

02-20-2014, 19:18	#53 (permalink)
terrymarsy Junior Member Join Date: Sep 2011 Posts: 2 Member: 1650705 Status: Offline Sonork: terry marsy Thanks Meter: 0	thanks ill take your advice and send it off to some1 with more experience

07-15-2014, 12:48	#54 (permalink)
AlgoJerViA Junior Member Join Date: Jul 2014 Posts: 1 Member: 2222880 Status: Offline Thanks Meter: 0	Hi I have replaced the digitizer on my nephews iPad Mini (A1432). At first I honored Murphy's law and soldered the digitizer on backwards on the digitizer chip board. It took me some time to realize what was wrong since Apple uses those wonderful error message in style with error #, do you want to check error # on the internet... error # means that something went wrong. However I resoldered the digitizer and now the home button and touch seems to work but the backlight died. This was before I know that I had to disconnect the battery and LCD in the right order so a current surge is quite likely. However, the backlight did come back for a short period of time (maybe about 30s) at least two times. I have tested the series of small fuses close to the LCD port and they are all fine. The larger fuse that is the most common failure has a resistance of about 700 Ohms that seems very high for a fuse. But is it even possible that the fuse has been partly burned, that seems very far fetch. Is it another path that cause this resistance and is this the excepted value when the fuse is burned? Both the 2R2 and the 4R7 have a resistance close to zero. However when I try to measure the diode I get no path in either direction. (I realized that now) So the diode is broken. But what about the fuse? Also do you have any suggestions how to best remove the EMI base, I have a hot air station if that helps. Also, there is a voltage drop about 4.x v over the diode, does that seem right? I have a local electronics store near here so is the characteristics know of the diode so that I can get a compatible replacement part without waiting the delivery? //AlgoJerViA

07-28-2014, 09:17	#55 (permalink)
chryslerdriver Insane Poster Join Date: Nov 2012 Location: Austria (Europe) Posts: 61 Member: 1842505 Status: Offline Sonork: 2344 Thanks Meter: 4	Hello and sorry for the late reply . Firstly (and I mean normally) the fuse is the main problem. Secondly the diode is broken (you don't get the diode at a normal electronic distributer, because it's a special one). Most people get the right diode at ebay or from a iCloud locked unit, and resolder it with wrong polatity! After that the backlight still doesn't work. Thirdly I've never ever had a broken IC, coil or controller. I can't answer your questions, because I'm on a business-trip and don't have access to my handwritten documents yet. Change the fuse and with luck the iPad should work again. Be very careful with the tiny connectors because it's easy to damage small components nearby when re-inserting. If you've checked everything assemble all shields carefully together and before reseating the touchscreen check if everything works (especially the digitizer). Soldering the IC to the digitizer is very complicated. I always buy the complete ones with the Hall-Sensor for detecting the original Apple case. There's always a possibility that a small range of the touch won't work because of short-circuit or anything else. Good luck

03-17-2015, 20:27	#56 (permalink)
z_zba Crazy Poster Join Date: May 2007 Location: MAKKAH Posts: 50 Member: 516667 Status: Offline Sonork: 100.1651000 Thanks Meter: 6	nice bro wwwoooowww this is work

11-05-2015, 11:00	#58 (permalink)
sqmaniak Junior Member Join Date: Oct 2015 Posts: 3 Member: 2480211 Status: Offline Thanks Meter: 1	Hi... I have iPad Mini A1454 with no backlight... I tried to jumper from component D8228 to C2250 directly and the backlight is on again... but when I made a jumper, I accidentally removed the L47012_WIFI component and now the component is missing... I turned on the iPad with no L47012_WIFI component and it's still working... But I cannot try to use the iPad because the digitizer is broken and I have purchased the new digitizer and still in the ship. So I cannot try the WIFI functionality... I fear that WIFI wouldn't work in the future... Say if the WIFI function wouldn't work when I attach the new digitizer, can I directly make a jumper with solder paste or wire in L47012_WIFI position? Please help me... Thanks

11-05-2015, 20:50	#59 (permalink)
chryslerdriver Insane Poster Join Date: Nov 2012 Location: Austria (Europe) Posts: 61 Member: 1842505 Status: Offline Sonork: 2344 Thanks Meter: 4	Hi! Unfortunately I'm on a business-trip and don't have access to my documents and PCBs. What is the L47012? Is it a coil or a necessary WiFi-IC? Wait until the Touchscreen arrives. Maybe it still works, now you can't do anything. Have a great day.

11-08-2015, 07:15	#60 (permalink)
sqmaniak Junior Member Join Date: Oct 2015 Posts: 3 Member: 2480211 Status: Offline Thanks Meter: 1	it's just a coil with blue color and a dot in it... I've pm you the pict... thx