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PB2400c doesn't boot. Is there anything useful information to fix it?

Kamomr

New member
Recently I got PB2400c from Yahoo Auction about $60. It was listed as junk, but cosmetically it seems okay, so I did bet.

After I got it, I disassembled it, and found some not-so-good situations.

1. Green crystals. Yes. PRAM battery has gone really bad. Fortunately, most of battery acid was on inner frame, and there are no visible corrosion on logic board and CPU daughter board.

2. Some of logic board screws are quite stripped. I did almost everything to undo them. Drilled to remove head, smack brass insert from back of frame to remove with inserts. All failed. Eventually, I cut inner frame to release brass insert.

However, I was able to completely disassemble and cleaned battery acid from my unit as much I can, and reassembled.

Now, second problem was I didn't have power adapter for PB2400c. So, I bought off-the-shelf 24V 2A DC adapter, and soldered 3.5mm stereo plug to build makeshift PSU.

When I connected power to unit, LED on display cover lit, but didn't response to power key.

I can hear little click sound from speaker when I press reset button located in back IO section, but still no sign of booting. I tried PMU/PRAM reset, but still no luck.

If I push reset button repeatedly, it keep cycling between green LED <-> speaker click.

During researching, I stumbled upon SMT fuses from this community. So I tested all fuses with multimeter and inspected visually, all fuses were okay.

I completely disassembled and rebuild it several times, but still nope.

It seems some kind of power is flowing through because when I put it still my unit after I hear speaker click, it became warm on the bottom.

At this point, I got little tired with my unit. It seems this thing is really broke, so only way to get working PB2400c is get one with smashed display or pay $700 for one equipped with G3/320 card. That's waaaay to much for me.

Is there any useful material to troubleshoot and fix my unit?

If not, I'm considering to sell this one as parts and get PB G3 or something can run classic Mac OS.

P.S. I was thinking to get 68K PB, but 2.5" SCSI HDD is keep away me to get one. Darn SCSI!

 
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beachycove

Well-known member
Most of these 2400c units will not boot without a functional backup battery (the green crystals). You just get the “Green Light of Death,” appropriately enough. Search “GLOD PowerBook,” and all shall be revealed, but the 2400c is the worst offender of them all. Notoriously so.

A backup battery can be assembled from a couple of Varta cells easily enough. I have a posting in here somewhere from years ago with the number. What may not be so easy is disassembling your 2400c to get at the area!

I might be interested in a parts machine, btw. Where did you see one for sale with broken screen?

 
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Fizzbinn

Well-known member
Most of these 2400c units will not boot without a functional backup battery
I thought the 2400c didn’t care if you removed the backup battery? In another recent post it was stated that the 3400c works fine without one and architecturally the are quite similar.





If the 2400c does require (or even benefit from) having a functioning backup battery I’m def going to look into building one ASAP! I removed it from my working 2400c for fear of it leaking and not to long after I could get it to boot.  I assumed other faults must have existed but if it’s “just” the backup battery...

 
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Byrd

Well-known member
Confirming no need for functional PRAM battery in 2400c; it doesn't need one to be reliable.  Also difficult to replace based on the tiny little area of plastic moulding one is supposed to fit into.

 

KnobsNSwitches

Well-known member
Just another confirmation for no need for a pram battery on the 2400 - I have been running fine without for a couple years now. 

 

Kamomr

New member
Most of these 2400c units will not boot without a functional backup battery (the green crystals). You just get the “Green Light of Death,” appropriately enough. Search “GLOD PowerBook,” and all shall be revealed, but the 2400c is the worst offender of them all. Notoriously so.

A backup battery can be assembled from a couple of Varta cells easily enough. I have a posting in here somewhere from years ago with the number. What may not be so easy is disassembling your 2400c to get at the area!

I might be interested in a parts machine, btw. Where did you see one for sale with broken screen?


I saw couple of posts that I need PRAM battery to boot, and others said opposite.

However, at this point I'll give it a try. I think I have some Varta cells around cabinet I bought to replace old Toshiba laptop's CMOS battery.

 

beachycove

Well-known member
The GLOD problem was erratic, with machines working some of the time, when the moon was full at Spring tides in leap years, with Mars bright in the night sky. Whatever. Perhaps the “most” in that post was an overstatement, but I certainly had one that absolutely refused to boot without a functional backup battery. GLOD all the way! And it was tried with no battery. It was apart ten or twelve times to access the internals, clean things up, and replace boards even. All it needed in the end was a ruddy battery.

The machine was designed to run with that battery preserving settings. Replacing it is a cheap and arguably the easiest option to explore in trying to get the thing running. That was my experience, and I think it is worth a shot here, even if the trouble turns out to lie deeper in the hardware.

 

Franklinstein

Well-known member
Sounds like this little 2400 has had a hard life. Unfortunately there really isn't a quick and easy solution for troubleshooting other than what you've already done: remove batteries, press reset button, check for obvious faults (burned or otherwise damaged devices, leaked capacitors, cracked solder joints, blown fuses, broken cables, etc). The most definitive solution now would be to swap parts until it works and then, if you know what you're doing, zero in on the problem part and try to figure out why it doesn't work. I've had every part of the 2400 models fail and most of them will present the GLOD so while that is often indicative of a benign power manager fault (caused usually by a leaky or just discharged PRAM battery), it's more often a sign that the machine can't power up for some reason. Maybe it's a bad or improperly seated CPU card. Maybe it's the power board. Maybe it's bad RAM. No idea without some part swapping.

Not super helpful, sadly, but the official troubleshooting steps from Apple say basically the same thing: swap parts until it works, then send the bad parts back to a depot for repair/refurbishment. I've never seen any official depot repair info for any Apple products so it generally stops there unless you're an EE of some sort and have access to lots of test equipment and SMD/multi-layer PCB repair tools. Even then if the fault is in a component that's NLA there's not much to be done about it.
 

macuserman

Well-known member
If your getting some noise out of it I would say that you should check and see if you get any video out on the external port. I’ve worked on several of these now and I always remove the battery no issues there but the more common issue is the inverter board and display being bad even if it looks fine. I have a suspicion you might get lucky and actually have a working bottom half with a bad screen.
 
Hi Everyone, this is happening to me now too, exact same symptoms. I recently went in to replace the HDD with a CF card and removed the CMOS battery after seeing just the slightest bit of corrosion on the frame (nothing on the logic board). I'll try putting the CMOS back in to see if that solves the problem. If it does, is there a supplier of these batteries somewhere? This one is clearly not long for this world.
 

3lectr1cPPC

Well-known member
I have to wonder if there is some small part that breaks easily when taking these apart. This same issue keeps happening. Working 2400c. Backup battery is removed, doesn’t work when put back together. Creating a new battery doesn’t fix it. Some people have removed it and been just fine. I just have to wonder if there is some *tiny* part that breaks super easily and causes GLoD on these. It would explain why some people have been fine removing the PRAM battery, while others have killed their PowerBook trying.
 

macuserman

Well-known member
I have to wonder if there is some small part that breaks easily when taking these apart. This same issue keeps happening. Working 2400c. Backup battery is removed, doesn’t work when put back together. Creating a new battery doesn’t fix it. Some people have removed it and been just fine. I just have to wonder if there is some *tiny* part that breaks super easily and causes GLoD on these. It would explain why some people have been fine removing the PRAM battery, while others have killed their PowerBook trying.
That seems very possible if you've ever taken one of these apart it's not a very fun picnic. Plus the screws are all different and it's really fun trying to remember where they all go.
 
Some good news! Turns out the PRAM battery had nothing to do with my GLoD booting issue. It took hours of assembly/disassembly but I got the thing to work again. I think the issue with the GLoD is the processor daughtercard not seated all the way.

When inserting the motherboard back in, both the power board and CPU card need to slot into connectors. Because of the orientation and the fact the power board is braced by the bottom case, it was easy for the CPU card to just not seat 100% into its two connectors. I verified this by fully removing all three boards and ensuring they had a tight fit.

I added some adhesive foam in between the daughtercard and powerboard that helped act as a brace to allow a tighter fit and allow the CPU card to fully slot.

I would imagine this issue is what is causing others' boards to appear dead as well since screwing everything back in can easily slightly cause the CPU board to misalign. I think I took it apart four or five times with it working when apart but dead when back together.
 

Fizzbinn

Well-known member
Some good news! Turns out the PRAM battery had nothing to do with my GLoD booting issue. It took hours of assembly/disassembly but I got the thing to work again. I think the issue with the GLoD is the processor daughtercard not seated all the way.

When inserting the motherboard back in, both the power board and CPU card need to slot into connectors. Because of the orientation and the fact the power board is braced by the bottom case, it was easy for the CPU card to just not seat 100% into its two connectors. I verified this by fully removing all three boards and ensuring they had a tight fit.

I added some adhesive foam in between the daughtercard and powerboard that helped act as a brace to allow a tighter fit and allow the CPU card to fully slot.

I would imagine this issue is what is causing others' boards to appear dead as well since screwing everything back in can easily slightly cause the CPU board to misalign. I think I took it apart four or five times with it working when apart but dead when back together.
Oh please, please let this be what’s wrong with mine…. Although I don’t want to get my hopes up too much, took a long time to get over seemingly killing it by removing the PRAM battery.
 

3lectr1cPPC

Well-known member
That sure would explain all those issues! if that's the case I would be a lot less afraid of opening one up, if I ever got one.
 
Oh please, please let this be what’s wrong with mine…. Although I don’t want to get my hopes up too much, took a long time to get over seemingly killing it by removing the PRAM battery.
I would certainly give it a shot. Best way to test is to take it apart and remove the frame too which holds the daughtercard and power board, then snap everything in really secure and plug in power (make sure the speaker is attached). With no batteries once power is connected I heard the chime and knew it wasn't really dead after all.

I think these machines are more resilient than it appears on the surface.
 
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