2400c questions:

imactheknife

Well-known member
Probably regurgitating old info and questions about this special laptop lol. Picked it up, paid to much, and tore it apart to remove pram battery which had leaked a little. Other than that everything looks nice. Plugged in, dead, nothing… tore it down and check solder and power plug and all fuses etc. nothing unusual. I did notice an area of the too logic board seems to get warm, not hot, when plugged in. No idea if this is good or not. First pick shows where it gets warm. Second picture shows where there was a little battey corrosion on the plug. Any ideas what else to check?
 

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finkmac

NORTHERN TELECOM
is the cpu board actually present?

i'm not kidding when I say 2/4 of mine were missing the cpu

if it is, reseat it. make sure it's in there correctly. test by hooking up the speaker connector and plugging in power

also... make sure you're keeping track of those screws. you'll regret it if you don't...

using the wrong screws in the wrong places can and will drill holes in your bottom case
 

imactheknife

Well-known member
is the cpu board actually present?

i'm not kidding when I say 2/4 of mine were missing the cpu

if it is, reseat it. make sure it's in there correctly. test by hooking up the speaker connector and plugging in power

also... make sure you're keeping track of those screws. you'll regret it if you don't...

using the wrong screws in the wrong places can and will drill holes in your bottom case
Lol, yeah the spoiler has happened unfortunately. It does have cpu card. Will reseat it again. Another question. The reset button was broken so i dont think it works. Could this be an issue for me to try a pmu reset? Will attach picture.
 

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finkmac

NORTHERN TELECOM
reset button isn't necessary for a chime, and pmu won't really matter I don't think.

bare minimum to get something out of it is cpu, logicboard, powerboard, and speaker. i usually test with just the board sandwich before screwing things together

chances are, if you do hook up the display, you'll see the "green light of death" which in most cases means "board sandwich not aligned properly"
 

imactheknife

Well-known member
reset button isn't necessary for a chime, and pmu won't really matter I don't think.

bare minimum to get something out of it is cpu, logicboard, powerboard, and speaker. i usually test with just the board sandwich before screwing things together

chances are, if you do hook up the display, you'll see the "green light of death" which in most cases means "board sandwich not aligned properly"
Ok, so if i get nothing it means problem is logic, cpu, or power board? Will try again. Just gave a quick isopropyl wash and air dry
 

imactheknife

Well-known member
So cpu is getting warm so i take it thats whats causing the upper board to get warm? Anyways, no change. Deader than elvis
 

imactheknife

Well-known member
stupid thought, try plugging headphones or a vga monitor in
Ok, well i can hear like an amp thud kick in through headphones but no chime. So at least it has signs of life. Nothing at all through vga. So either I can’t get it to actually turn on, or there’s is something wrong. Weird the cpu gets really warm. So must be on somehow?
 

finkmac

NORTHERN TELECOM
when you plug it in, it'll power up. don't need the power button for that. can't say I've ever seen that failure mode. inspect all the boards carefully
 

imactheknife

Well-known member
when you plug it in, it'll power up. don't need the power button for that. can't say I've ever seen that failure mode. inspect all the boards carefully
Ok, so it sounds like it is “turning on” just not an actual chime, and no display etc. will take a look at boards closer. I checked all fuses and i am guessing power board must be ok? I am using a good known power supply from g3 powerbook.
 

3lectr1cPPC

Well-known member
If all the fuses are good and you can't find any bad traces or vias, I'm out of ideas. Must be another board-level defect. This is where a schematic would come in handy, if only we had one...
 

Powerbook27364

Well-known member
Mine acted similar at first but had a solid green light. After a fair bit of trial and error re-seating the boards, I got it to power on and it works fine now. The CPU did get warm and there was no chime or video, but I don't remember if I heard the speaker kick on or not.

My 2400 also had much worse corrosion, so I doubt the corrosion killed it, but there is always the chance it got into a via or something.
 

imactheknife

Well-known member
Mine acted similar at first but had a solid green light. After a fair bit of trial and error re-seating the boards, I got it to power on and it works fine now. The CPU did get warm and there was no chime or video, but I don't remember if I heard the speaker kick on or not.

My 2400 also had much worse corrosion, so I doubt the corrosion killed it, but there is always the chance it got into a via or something.
Good to know, thanks! Gives me hope at least. Did your hard drive spin up when you were having similar issues, or was it just dead but with warm cpu with no chime / video?
 

imactheknife

Well-known member
If all the fuses are good and you can't find any bad traces or vias, I'm out of ideas. Must be another board-level defect. This is where a schematic would come in handy, if only we had one...
Yeah well, the little noise gives me hope lol. Cpu is warm, just not sure if / how to seat it better than i am? Whats responsible for chime? Cpu card? Or rom on logic board?
 

Powerbook27364

Well-known member
I unfortunately dont remember if the drive spun up since its been a while.

Speaker pop means at least something is happening. I found a photo of my test setup for it at its just the boards put together on some bubble wrap. If you can try that, you should be able to get the boards lined up much easier. Check for any bent pins when you are working on it though... I learn a lesson after spending several hours working on 2 540c laptops only to find out some pins were bent.

I dont know which is responsible for the chime, but both need to be functional.
 

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MacUp72

Well-known member
from the photos I dont see any really bad corrosion, apart from the darker area with the little PRAM battery connection socket..
fuses, I dont know if they all are soldered in-types, but in many cases it turned out some were indeed blown, it is littered with those fuses ( theres a thread here somewhere with detailed photos)
edit: found it..

photo is not the best, there seem to be some solder marks?..guess the last owner poked around with a soldering iron;)

Bildschirmfoto 2024-07-12 um 10.06.09.jpg

maybe it also helps checking the Schottky diodes ( SS..) must be near the power plug socket. And the voltage regulator.
I only have this photo of my 2400, of the underside of the power board

Bildschirmfoto 2024-07-12 um 10.14.10.jpg
 
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