Powerbook 3400c Troubleshooting!

[lapalace]

Hey hoping someone with experience troubleshooting these 3400cs might be able to help me here! Grabbed PowerBook 3400c for £20 in unknown condition and it's in pretty good condition. However, I haven't been able to get it to power up. The symptons are: a super barely audible high pitch and a crackle indicating some sort of power is getting to the board. I can get the power LED to go green if I hold PRAM reset key combo or hold the reset button on the back but it still gets no further. I have swapped out the DC power board with two others and the symptoms remain consistent. The only sign of damage I can see is corrosion at the back of the board near the DC jack but *none* on it. It seems to be affecting these three resistors: R48, R51, R53. But everything else seems fine, including caps. Could it just be these resistors?! Any help or insight would be appreciated! Thanks

 

[DarthNvader]

Delicately clean the corrosion and retest.

Corrosion is never good.

 

[MacUp72]

old story, exactly over this whole area ( under the speaker panel) sits the green Varta PRAM battery of death, when it once leaked and electrolyte dripped onto the components beneath it, it is likely damaged/dead ( 47uF cap area)..I had two machines with little corrosion there, also did pay for a ultrasonic cleaning, but and it never booted again properly.

 

[lapalace]

old story, exactly over this whole area ( under the speaker panel) sits the green Varta PRAM battery of death, when it once leaked and electrolyte dripped onto the components beneath it, it is likely damaged/dead ( 47uF cap area)..I had two machines with little corrosion there, also did pay for a ultrasonic cleaning, but and it never booted again properly.

View attachment 82800

Hm, okay. PRAM battery was fine when I took it out, no sign of corrosion so not so sure why my machine is corroded where it is.

 

[MacUp72]

oh, mine didnt look bad either..maybe you can see some green corrosion that wicked through the cable/ connector..