Yol
30-03-2006, 05:24 PM
Hi all,
As i started servicing all pdas for a couple of monthes (only as a hobby, i fix them for friends and relatives), i came across one BA that gave me some trouble.
i got it to replace its LCD that was broken as it was dropped and thats very simple to replace it, so far so good. now it has two main problems :
1. no sound from speaker (even when in speakerphone mode), but there is sound in the stereo earphones (i plugged to the connector by the sd card slot). - i can only assume that a bluetooth handsfree device it will also work.
2. although the backup battery is fully charged, if i remove the main battery even for a brief second, when turned on, the BA acts as if i made a hard reset.
as for solving the problems :
1. using a digital multimeter, i managed to track the conductivity from the internal speaker through its connector, flat ribbon to the connector which connects to the main pcb - so there is no contact problem from the speaker to the main pcb.
using the help from WIKI, i went to site that has the list of all components and their description - the IC that is responsible for audio amp is a MAXIM's MAX4410 which is a stereo headphone driver. a quick look at its charasteristics and typical configuration and i understood that (assuming this is the IC that drives the internal speaker) the speaker should have one pin which is ground and the other goes to the amplified signal from the IC. neither one of the pins showed it has GND to it. so maybe there is a bad GND line to the connector.
2. regarding the backup battery issue i do not know what makes this problem.
I am sharing this info with you all with two ideas in mind :
1. to resolve my problem and know those devices hardware better.
2. because i am quite a while watching xda-developers and WIKI and i got the feeling that a lot of eforth is given to the software side of all those pdas (which is greate!!! keep going, this work helps lots of people and it shows al thos mega corps they are not the only ones), but the hardware is a bit forgotten and left behind. let me tell you this, there are many VERY simple mini projects i made useing electronics (i am an electronics engineer in my profession) that made my life easy . i am now investigating those instruments hardware as i have several ideas to develope useful accessories to my pda (like an external IR transciver to control IR devices like TV,DVD and to communicate with my laptop, and some other ideas) and i believe we can do the same info sharing as done on software side but on the hardware side.
I will thank any ideas, thoghts or commentsabout this matter. Yol.
As i started servicing all pdas for a couple of monthes (only as a hobby, i fix them for friends and relatives), i came across one BA that gave me some trouble.
i got it to replace its LCD that was broken as it was dropped and thats very simple to replace it, so far so good. now it has two main problems :
1. no sound from speaker (even when in speakerphone mode), but there is sound in the stereo earphones (i plugged to the connector by the sd card slot). - i can only assume that a bluetooth handsfree device it will also work.
2. although the backup battery is fully charged, if i remove the main battery even for a brief second, when turned on, the BA acts as if i made a hard reset.
as for solving the problems :
1. using a digital multimeter, i managed to track the conductivity from the internal speaker through its connector, flat ribbon to the connector which connects to the main pcb - so there is no contact problem from the speaker to the main pcb.
using the help from WIKI, i went to site that has the list of all components and their description - the IC that is responsible for audio amp is a MAXIM's MAX4410 which is a stereo headphone driver. a quick look at its charasteristics and typical configuration and i understood that (assuming this is the IC that drives the internal speaker) the speaker should have one pin which is ground and the other goes to the amplified signal from the IC. neither one of the pins showed it has GND to it. so maybe there is a bad GND line to the connector.
2. regarding the backup battery issue i do not know what makes this problem.
I am sharing this info with you all with two ideas in mind :
1. to resolve my problem and know those devices hardware better.
2. because i am quite a while watching xda-developers and WIKI and i got the feeling that a lot of eforth is given to the software side of all those pdas (which is greate!!! keep going, this work helps lots of people and it shows al thos mega corps they are not the only ones), but the hardware is a bit forgotten and left behind. let me tell you this, there are many VERY simple mini projects i made useing electronics (i am an electronics engineer in my profession) that made my life easy . i am now investigating those instruments hardware as i have several ideas to develope useful accessories to my pda (like an external IR transciver to control IR devices like TV,DVD and to communicate with my laptop, and some other ideas) and i believe we can do the same info sharing as done on software side but on the hardware side.
I will thank any ideas, thoghts or commentsabout this matter. Yol.