PowerPC G3 Daughter board Problems

[Rikintosh]

I have some G3 Lombard Powerbooks, and some of them have a problem with the daughter board, I'm sure it's this board, because I removed the same board from another drive to put in the faulty drive, and it worked perfectly. But I don't want to have to throw away these defective daughter boards and have to buy new boards for replacement, I wish I could fix them.

Has anyone here ever had something like that?

Let's go to the symptoms:

- When plugging the charger into the machine, the green light will turn on, and will stay on constantly. The normal would be to turn the hd on, turn it on, and then turn it off. This doesn `t happen. It just has the green light on all the time. After some time it is possible to feel that the processor has warmed up. It doesn't matter whether the batteries are connected or not, the symptom will be the same. So, unplugging the charger, and then plugging it in, will make the light go on and off like it should (not exactly, it does this too quickly than it should), so the processor won't heat up anymore, and it won't turn on so some. Pressing the reset button will have the same effect as plugging and unplugging the charger.

If I leave it for a few days without power, occasionally it will turn on, sometimes it will just play the startup sound, and it won't show any image. Other times it will boot the system, but VERY VERY SLOW! And it will crash at some point. The problem has gotten worse and worse, and it will hardly show a picture now.

I measured the daughter board with a multimeter, and while the green light stays on, the board has the voltages it should have (1.9v, 3v, 4.75v), but when I unplug the power supply, and plug it in again, it will flash the green led only, then there will be no voltages other than 0.50v.


It's funny that I have an iMac g3 233mhz, with the same problem, I'm sure it's also a problem with the processor board, as I tested the machine with another imac's processor, and it worked perfectly.

I believe it's a common defect on these boards, but I don't have their wiring scheme to try to fix.

Does anyone here have this problem? Got a solution? Any tips or guess where to start?

 

[galgot]

I've read about the same problem on a PowerBook G3 Wallstreet 233Mhz. The way it was solved was to start once the PowerBook WITHOUT the daughter board , unplug everything , then put back the daughter board and go...

Note the same symptoms also happened to me on a PowerBook G3 Cache-less mainstream 233Mhz, I had a spare 233Mhz daughter board with cache and just did the swap, I never tried the trick above as I found it later.

But then your is a Lombard ... so. Dunno.

 

[Rikintosh]

I've completely dismantled it, cleaned everything up, and reassembled it, but no luck

 

[galgot]

Well, sorry about that. Have you tried the trick above, plug it to power supply, hit the start button without the daughter board in. Then unplug everything, put back the daughter board and try.

Other problem with Lombards and Pismos is the daughter board can be quite hard to put back correctly in place, one has to press a lot . Some time one thinks the thing is correctly in place when its just not pressed enough on the sockets and makes no contacts.

Another thing to see : is the PRAM battery still there ? If so unplug it. Dead Pram battery can prevent Pismos from booting,
not sure about Lombards, but worth trying.

Also, I've revived one or two Powerbooks by leaving them shutdown but plugged to power supply for a night...

 

[Rikintosh]

Well, sorry about that. Have you tried the trick above, plug it to power supply, hit the start button without the daughter board in. Then unplug everything, put back the daughter board and try.

Other problem with Lombards and Pismos is the daughter board can be quite hard to put back correctly in place, one has to press a lot . Some time one thinks the thing is correctly in place when its just not pressed enough on the sockets and makes no contacts.

Another thing to see : is the PRAM battery still there ? If so unplug it. Dead Pram battery can prevent Pismos from booting,
not sure about Lombards, but worth trying.

Also, I've revived one or two Powerbooks by leaving them shutdown but plugged to power supply for a night...

My laptops no longer have the pram battery, but they would work even without it. Only the pismos will not boot without a pram battery.

I'm sure it's a defect in the board itself, in some component, because I tested this daughter board on other machines and the result was the same, as I tested other daughter boards on the machine it was on, and the machine worked