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Powerbook 100

PostPosted: Fri Sep 12, 2014 11:40 pm
by Clym5
Hello again, I feel like I'm here a bit too often..

I just picked up a PB100 that hasn't been used for a very long time. It has been stored well, and it was working before being stored too.

The internal battery is shot. It's lead acid, and been sitting at 0v for wayyyy too long. Tiny little leak in the corner too.

Apart from that, the machine seems perfect in condition. No strange smells either.
But, as per usual, it doesn't do squat diddly. I managed to get the backlight to flash for a split second.

I tried both positions for the switch at the back, to do with the battery, and I've had a good go at the two buttons on the side. Interrupt and one other.
No noise, no nothing. I am using the original 7v 2A wall wart, which stays stone cold.

Anyone got any tips to finding the culprit, or have had this issue before?

Re: Powerbook 100

PostPosted: Sun Sep 14, 2014 12:56 pm
by Clym5
Just checked the 7.5v charger on a multimeter, and the voltage starts at 10v, then drops to 7 and slowly drops to 0v over 5 minutes. It would seem that the charger is shutting itself off very quickly after it is plugged into the mains, and the slow voltage drop is a capacitor retaining charge.

Or is that just a characteristic of not having any load on the charger?

Re: Powerbook 100

PostPosted: Sun Sep 14, 2014 1:15 pm
by tezza
Clym5 wrote:Just checked the 7.5v charger on a multimeter, and the voltage starts at 10v, then drops to 7 and slowly drops to 0v over 5 minutes. It would seem that the charger is shutting itself off very quickly after it is plugged into the mains, and the slow voltage drop is a capacitor retaining charge.

Or is that just a characteristic of not having any load on the charger?

I don't know how these things work so I'm not sure. Sorry I can't be of more help.

Re: Powerbook 100

PostPosted: Mon Sep 15, 2014 12:36 pm
by Beags
Hi Clym5, I myself am in the midst of a Power Book 100 restoration (see earlier PowerBook 100 post). I can't give you any suggestions re the power pack/charger but I do have a couple spare. Interested?

Re: Powerbook 100

PostPosted: Mon Sep 15, 2014 12:58 pm
by Beags
Or maybe whats a little easier, I will put my multimeter on a known working one at home and I will let you know the results.

Re: Powerbook 100

PostPosted: Mon Sep 15, 2014 1:24 pm
by Clym5
Ah, thanks Beags! I'm 90% sure the power pack is the blame, as the backlight turns on for a split second, just like the power supply.

I could always make a 2A 7.5V DC power pack, but that'd be a real pain, and the only pre-made ones I can find don't even come close to 2A.

Re: Powerbook 100

PostPosted: Mon Sep 15, 2014 6:39 pm
by Beags
I have checked the voltage on the power pack and its a steady 7.7ish volts for more than 2 minutes, so yours is naffed!!! I will PM with my details.

Re: Powerbook 100

PostPosted: Tue Sep 16, 2014 9:41 am
by lizardb0y
In my experience Powerbook PSUs are damnably unreliable. I have a number of dead ones myself. Good luck getting the PB100 running!

Re: Powerbook 100

PostPosted: Tue Sep 16, 2014 1:41 pm
by Clym5
My original plan was to pop the power pack open, gut it, and solder up my own board to drop in. But thanks to Beags, I won't have to do that for now!

There still may be issues with the PB100, like a stuck hard drive, but for now, I can't check.

I've still got to get my Toshiba T3200SX going, and my BBC Master (it was used at NASA!) working again. Hopefully the PB100 is a quick fix.

Re: Powerbook 100

PostPosted: Sun Nov 23, 2014 12:30 pm
by Clym5
After recapping the motherboard and cleaning the mess the old caps left behind, it still doesn't work 100%. The screen likes to display two lines, and the HDD just rattles. I do get the proper start sounds though!

I was told by a PowerBook user from when it was around that this happened sometimes, and he'd leave his PB on a small heater to get it toasty. I did this with my heated blanket in my bed, and bam! It works! Only when rather hot though. The screen is fine, HDD is fine, and I poked around the PB for a bit. As soon as it got cold, it was dead again. Maybe I missed a cap? I hope not..

Re: Powerbook 100

PostPosted: Sun Nov 23, 2014 7:58 pm
by arjoll
Two comments I'd make here.

Firstly, how does it go without the battery on? I know the PB180 is newer, but we used to have one at work to read accounting data from Mac users (early 2000's) with a stuffed battery and it would only fire up with the battery disconnected.

Secondly, only running when hot sounds almost like a resistor has gone out of spec, but I'd be surprised if anything post-1970 would have resistor problems! You may need to try a combo of heatgun and freezer spray to identify where the problem is...

Re: Powerbook 100

PostPosted: Sun Nov 23, 2014 8:58 pm
by Clym5
I run the PB with the battery out only because I don't like putting power into the ruined, slightly leaking, and maraca-sounding battery. Doesn't seem to worry it at all. It also works with the battery in too.

One symptom I noticed is that it tries to power up as soon as I plug the charger in. Kind of.. Backlight turns on, and I get varying volumes of what sounds like 50 cycle hum. It would of been produced in the Mac, as I've had the PSU on a 'scope, and it was fine. Pressing both of those side buttons shuts it off, and then pressing the keyboard boots it.

I talked to that guy again today, who heated his PB up. He said the caps drift back into spec in the heat. I must of missed one! Drat!

Re: Powerbook 100

PostPosted: Mon Nov 24, 2014 8:29 am
by LilJoe
Clym5 wrote:I've also never had a capacitor fail in any computer, which I consider a bragging right!

Clym5 wrote:After recapping the motherboard
I think those caps just cost you your bragging rights :D

Good luck with the repair

Re: Powerbook 100

PostPosted: Mon Nov 24, 2014 12:24 pm
by Clym5
Haha, drat! I'm going to stick by what I said, as the PB does still work! Caps hadn't completely failed yet! I just had no video unless it was hot.

I'm sure I won't be able to claim that much longer though!

Re: Powerbook 100

PostPosted: Thu Dec 18, 2014 5:14 pm
by mehimu
Some days ago i was also facing this type of problem while working some this type of tools, anyway, nice discussion and it helps me to gain some knowledge