Hi there
Years ago, I finally got hold of a M5126 backlit Portable. It was untouched, never before been worked on. I was not surprised that it didn't boot and only produced a garbled screen, similar to a Simasimac.
I removed the caps, cleaned the board thoroughly, soldered new caps. Same thing. The board is as clean as can be, no dull vias visible, no corrosion from cap goo. I gave up back then, couldn't find a good reason why it shoudn't work. Thanks to Corona , I rediscovered the Portable and decided to tackle the problem again. I removed all the caps, double-checked every pad, via, track in the surroundings of the caps, ultrasonic-cleaned the board again, dried it, resoldered new caps. Same thing.
Maybe somebody can point me in the right direction to check things. After applying 6.5V to the battery terminals, the board pulls around 60mA on my lab supply. After PMU reset, it goes down to around 20mA. I can then power the unit up with the space bar, it pulls ~780mA with the backlight running. Yes, most of the time it starts up with the backlight running. I hear a faint whine/hiss from the speaker, which changes pitch after about half a second and then stays that way. Most of the time it powers up to horizontal bars with pixels, slightly changing every time I power it up, with sometimes varying display contrast. Sometimes it powers up to a completely black screen.
I do have SMT soldering /rework equipment, a scope, etc., however, I am kind of lost here what to check first and hope that somebody has experience fixing these boards and can point me in the right direction of a probable fault. Hopefully the screenshots give some clues? I'd appreciate any help and shared experiences which might help get my 5126 back running. I do have a 5120 parts donor board, however that seems to only be of limited use for a 5126 repair. I'd go as far as saying that the Portable probably died before it died because of bad caps. I had 5120 running which were far worse looking in terms of cap leakage...
Thanks!
MacGyver
Years ago, I finally got hold of a M5126 backlit Portable. It was untouched, never before been worked on. I was not surprised that it didn't boot and only produced a garbled screen, similar to a Simasimac.
I removed the caps, cleaned the board thoroughly, soldered new caps. Same thing. The board is as clean as can be, no dull vias visible, no corrosion from cap goo. I gave up back then, couldn't find a good reason why it shoudn't work. Thanks to Corona , I rediscovered the Portable and decided to tackle the problem again. I removed all the caps, double-checked every pad, via, track in the surroundings of the caps, ultrasonic-cleaned the board again, dried it, resoldered new caps. Same thing.
Maybe somebody can point me in the right direction to check things. After applying 6.5V to the battery terminals, the board pulls around 60mA on my lab supply. After PMU reset, it goes down to around 20mA. I can then power the unit up with the space bar, it pulls ~780mA with the backlight running. Yes, most of the time it starts up with the backlight running. I hear a faint whine/hiss from the speaker, which changes pitch after about half a second and then stays that way. Most of the time it powers up to horizontal bars with pixels, slightly changing every time I power it up, with sometimes varying display contrast. Sometimes it powers up to a completely black screen.
I do have SMT soldering /rework equipment, a scope, etc., however, I am kind of lost here what to check first and hope that somebody has experience fixing these boards and can point me in the right direction of a probable fault. Hopefully the screenshots give some clues? I'd appreciate any help and shared experiences which might help get my 5126 back running. I do have a 5120 parts donor board, however that seems to only be of limited use for a 5126 repair. I'd go as far as saying that the Portable probably died before it died because of bad caps. I had 5120 running which were far worse looking in terms of cap leakage...
Thanks!
MacGyver