Author Topic: EEVblog #295 PLZ help me to repair this Ebook reader  (Read 1920 times)

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Offline Ranatungawk

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EEVblog #295 PLZ help me to repair this Ebook reader
« on: June 25, 2012, 03:45:09 am »
 I’m writing this expecting a troubleshooting advices from you to fix my Chinese eBook reader, which is  exact similar to the eBook reader you discussed in “EEVblog #295 - $30 eBook Reader Teardown”. I spent $47 for this. Even though it’s a small amount in ur country, it’s a somewhat big amount for a guy who live in a developing country—like me : -)  So I hope that you will put your kind attention on this .. :)
 
Problem:
 
I used this Ebook reader since 4 months. Recently I charged it and forgot to stop charging until 12 hr. after 12 hr. I removed it from the charger. Till then, it cant be turned on (no power at all, it’s dead). One or two times it came up but after 1min got down again. However, now it doen’t come up at all. Then I opened the ebook reader and  removed the battery and kept 1or 2hr and tried to ON, but it’s still dead.  When I connect the ebookreader to the charger, I found SS14 diode, which is at PT1502, get heated.!!

What I have done so far..:

According to the data-sheet of PT1502, as far as I could understand, when power button is pressed 3v-5v signal should come to the PT1502 in order to turn on the CPU. However, when I check, I found voltage on the above pin is around 2.51v. Can this be a reason ??? I identified this voltage come to PT1502 through a SMD type SCHOTTKY DIODE (KL3). When switch is off, 4.07V come to the switch, but it’s dropped 2.51 when button is pressed.
 
First I thought it was a faulty of PT1502 or SS14. So I replaced the both items with new ones. But the issue remains same.
 
So can you please give me a advise to fix this ?
 


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