• Please review our updated Terms and Rules here

Powerbook 100

N

novastar

Member
Joined
Mar 4, 2015
Messages
31
Hello, I'm new to this forum.

I've acquired a dead Apple Powerbook 100. Cosmetically, it's in great condition and I've always wanted one but there was no power supply so I had to use a general purpose laptop 7.5V 2.25A adaptor (it's great that these old machine uses standard connectors!). I had to reset the system a few times with the reset/programmer buttons on the side but the screen lights up and it chimes. But there's nothing more than that.

This is an odd system in that doesn't seem to be an actual power button. From what I've read it starts automatically when you tap any key if there's power? I bought some new cell batteries for the fold out holder which I believe power the clock (PRAM) and preserve the RAM. Can anyone elaborate on how this is supposed to work?

Obviously the battery is dead and the hard drive, an original 20MB Apple one from '91 is probably toast. I'd be happy to get to get it to the 'insert floppy' icon at this point. The machine came with the an external floppy drive and have the means to make system 6/7 startup disks (I use mini vmac on my iMac, have bought a USB floppy drive and have an old G3 iBook that runs OS9). I have a long history with macs.

I'm aware that systems of these vintage typically need to be recapped. I've done some research in this area, i have the basic tools and a background in electronics.

I found this site (http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/1991/10/21_PowerBook_100.html) which lists all of the capacitors in the machine.

Is there a way to test which caps actually need to be replaced? I tried to measure the resistance across them but couldn't get anything on the meter (either that it was very high).

The surface mount caps are almost certainly toast. There's powdery residue around the bases and the contacts.

Rather than desolder them, it looks like most restorers simply twist the the cans off the plastic platforms with pliars. This seems dangerous to me as it could lift the delicate pads from the board. Is there a simpler way?

Is it really necessary to replace the radials? They look OK, no residue.

Any tips appreciated.
 
I started recapping the board, starting with the surface mounts, only to find that the capacitors I had were too big. There's very, very little clearance on the board once the CPU card, RAM card and keyboard are re attached (the keyboard sits at about 1.25cm above the mobo).

I ordered some tiny low profile caps which arrived today. I had no problem removing the old caps and cleaning up the board however. I used pliers to cut into the cans which then lifted right off, leaving the plastic base, connectors and pads in place. Really surprised how easy it was.

I also discovered another cap on the trackball assembly and too more on the LCD board. It looks like there may be some tiny ones on the back of the panel too. So many caps!

I've taken photos and might post them if anyone's interested.
 
I recapped mine with regular standard profile radial caps (I had a large selection on hand already), just laid them down on their sides and leads folded over, some people will use SMD Tantalum caps, which are more expensive, but low profile, and will never leak since there's no liquid electrolyte. For their removal I did twist most mine off, some took some heat from soldering iron, but most were so rotten they just pulled free with very little force, as I find is often the case with these rotten aluminum SMD caps.

I have yet to recap the LCD on mine, it's working OK right now, but I know some day I will need to recap it too, for that I will probably go with Tantalum SMDs, I don't think there's room for regular radial caps in that.
 
Thanks for the reply RMallmow :p

I couldn't fit standard profile caps in no matter what I tried. There's a tightly packed cluster of SMDs to be replaced near the power transistors. I couldn't see anyway of doing it given the space available.

But my low profile caps have finally arrived and they're definitely fit.

I've started a new blog with my progress: http://novastar.pen.io/
 
I cut he cans as well, never had any trouble so far (once the head is removed, de-soldering is easy)

I use tantalum caps to recap my boards, because they are tiny and won't leak on the future.

Remove and replace all the caps, they have the same age...so won't last forever.

Concerning the HD, once recapped see if the HD burst into life again, if not maybe suffering from stiction (if desperate try to remove the cover and move the head...can work for a while)
 
Great news, the HD is an issue and won't be easy to replace.

Congrats on the repair.
 
Nice work! I uploaded my PB100 repair and restoration log to youtube a few years ago. Ended up going with a compact flash HDD.
 
Thanks! Yes the HD is a problem. Its the original 20MB Connar drive and the heads stick.

I was able to get it working by giving it a really, really hard bash with a screwdriver handle while booting but the heads get stuck again if I turn the machine off and I have to repeat the procedure. The drive itself seems fine once it starts; I've installed software, ran Norton Utilities on it etc. The heads just go back to being stuck when parked. It's a shame.

The Quantum Go drive from the PB140 was in worse shape. No stuck heads but lots of bad blocks and read/write errors.

I would buy one of those CF adaptors from Japan if I wasn't worried about the import charges (I used to import a lot of stuff until they UK customs started adding import duty to everything), but I'll probably end up ordering one. Any suggestions?

I managed to find a 2.5" scsi on ebay for a very reasonable price and it arrived today so fingers crossed. The guy said it was pulled from a working Duo.

I've been really lucky with this machine. It's in a near mint conditions; in fact I don't think it's seen much use. The seller found it in an office move and didn't know anything about it. The Connar drive had Disk Doubler and some ancient Word documents on it but just testing stuff. I'm guessing it was bought by a company, used for 10 mins and then forgotten about.

The screen is like new as is everything else. The plastic on the keyboard, trackball buttons and palm rest shows no sign of use. The data and time is preserved as is the RAM disk contents (once I added fresh cell batteries that is).

I've played various games on it and left it running for some time. No errors, screen tunnelling or anything like that. I had to find and install System 6.0.8L to enable the brightness and contrast dials.

Figuring out how to write HFS floppies from OSX proved a challenge but I've cracked it now.

There are a few problems remaining:
- The speaker occasionally emits a popping sound as if it's picking up interference. Any idea what this could be? It's rather annoying.
- When the machine is first booted, a brief checkerboard is displayed on the screen before disappearing. I thought this could be the result of a loose connection by I double checked all of the sockets (it also does it if the RAM expansion is removed although the pattern changes).
- The lead battery is dead, as expected. I'm thinking of gluing the bezel to the front and adding my own rechargeable in the bay, there's plenty of space. Does anyone have any suggestions?

I've not replaced the caps in the inverter board or on the back of the LCD. I have the parts and the skills but would rather not touch those unnecessarily. The brightness and contrast controls work OK but I think the pot for the former is a little sticky.
 
Another update.

The Duo drive I found on ebay seems to be working OK but it occasionally makes a 'click' sound which can't be good. And oddly enough Apple HD SC Setup actually crashes if I try to format it. But Norton reports no problems.

Still considering a PowerMonster but it's pricey and I've seen reports that I doesn't work in the PB100 without modification. It would cost more than the PB100 did.

The SCSI2SD is intriguing but they're reported as out of stock.

I would really like to repair the original 20MB Connar drive. As I mentioned, it's seen very little use and only sticks on a cold startup. Once it's 'persuaded' to start it's absolutely fine. I suspect the heads are stuck in the parked position from being left to sit for so long rather then being in contact with the platters. Is there anyway I could lubricate it somehow? I'm not worried about opening the drive up.
 
If it's something simple, like a stuck shipping latch, then that should be OK as long as you work quickly. I seem to remember Conners of this vintage having that specific problem. Anything else would require special tools and a way to realign and re-lubricate the heads and platters, which I understand isn't easy (though data recovery places have ways of doing it).
 
The rubber Conner used turns to a gooey sticky mess, seals will do it for sure, and if they use a rubber head stop it could very well do it too. Not unique problem to Conner, but they are notorious for pretty much ALL their drives doing it, not if, but when.
 
Congrats on getting the machine to boot! :)

novastar said:
- The speaker occasionally emits a popping sound as if it's picking up interference. Any idea what this could be? It's rather annoying.
Click to expand...

This is quite normal and I've had other early Powerbooks do the same. I believe it is caused when the power management shuts down the audio circuitry after a period of inactivity.

novastar said:
- When the machine is first booted, a brief checkerboard is displayed on the screen before disappearing. I thought this could be the result of a loose connection by I double checked all of the sockets (it also does it if the RAM expansion is removed although the pattern changes).
Click to expand...

Again, I've seen this on most PowerBook 100's. I think its just a case of the system initializing other hardware before it gets to the video RAM.

As has been mentioned, check the rubber drive seals on the hard drive. I've had to replace nearly every connor drive I've come across in laptops recently due to the rubber turning to goo :(

Cheers,
Dave
 
I didn't have to make any modifications to get the powermonster to work in my PB100. Worked like a charm. Booted to a floppy and initialized the "disk" (512 MB CF) and off i went.
 
I'm worried that the rubber pads between the heads and the platters have rotted away. If that's the case, the writings on the wall.
 
Moonferret said:
Congrats on getting the machine to boot! :)

This is quite normal and I've had other early Powerbooks do the same. I believe it is caused when the power management shuts down the audio circuitry after a period of inactivity.

Again, I've seen this on most PowerBook 100's. I think its just a case of the system initializing other hardware before it gets to the video RAM.

As has been mentioned, check the rubber drive seals on the hard drive. I've had to replace nearly every connor drive I've come across in laptops recently due to the rubber turning to goo :(

Cheers,
Dave
Click to expand...

That's good to know. Did they exhibit the same behavior when new?
 
I took the Conner drive apart and it was in very good shape, no goo. I was surprised. And there was only a single platter. I couldn't see why the heads were sticking but after moving them back and forth from the park position, it booted fine. If I leave it for a couple of days it goings back to sticking again and needs tap from the side. It boots surprisingly fast and sounds like new. I guess it's just a case of using it.

I've got some more questions for you guys.

I've replaced every cap now apart from the 3.3uf ones on the back of the LCD panel. I've taken the panel apart to see if I can get at them more easily but the plastic frame seems to be attached to the PCB and the only access is through a small window. Now the LCD is working but without another PB100 to compare it too I've no idea how good it's supposed to be. It exhibits shadow artefacts and some ghosting but that's probably just the nature of super twist displays. There's no obvious corruption and the image remains steady after extended use. The range for the contrast pot seems very high and the brightness pot (which seems to change the back-light intensity trough software) is a bit sticky. I have changed the caps on the inverter board but it had no benefit.

Is it necessary to replace these caps or am I pushing my luck? There is some powdery residue around the contacts.

The system doesn't always retain the date/RAM disk. I've read that the spring switch on the battery compartment will (when closed) cause the system to try to draw power from the (dead) battery instead of the coin cells. But the first thing I did was remove the battery.

The trackball is a bit sticky. There are two posts that it rests on and they're slightly warn. I've given it a good cleaning but nothing helps. Is there a way to rotate the posts so that ball is resting on the unworn surfaces?

Is there anyway to open the lead acid battery? I would like to replace the contents with rechargables. Ideally these would charge from the existing circuitry but I've read that lead acid cells charge in a fundamentally different way from modern NiCads.

Finally, I have a modem card which I pulled from a (dead) PB140. It appears to be compatible with the PB100. Is this card of any use at all or is it just junk now in 2015?
 
novastar said:
I took the Conner drive apart and it was in very good shape, no goo. I was surprised. And there was only a single platter. I couldn't see why the heads were sticking but after moving them back and forth from the park position, it booted fine. If I leave it for a couple of days it goings back to sticking again and needs tap from the side. It boots surprisingly fast and sounds like new. I guess it's just a case of using it.

I've got some more questions for you guys.

I've replaced every cap now apart from the 3.3uf ones on the back of the LCD panel. I've taken the panel apart to see if I can get at them more easily but the plastic frame seems to be attached to the PCB and the only access is through a small window. Now the LCD is working but without another PB100 to compare it too I've no idea how good it's supposed to be. It exhibits shadow artefacts and some ghosting but that's probably just the nature of super twist displays. There's no obvious corruption and the image remains steady after extended use. The range for the contrast pot seems very high and the brightness pot (which seems to change the back-light intensity trough software) is a bit sticky. I have changed the caps on the inverter board but it had no benefit.

Is it necessary to replace these caps or am I pushing my luck? There is some powdery residue around the contacts.

The system doesn't always retain the date/RAM disk. I've read that the spring switch on the battery compartment will (when closed) cause the system to try to draw power from the (dead) battery instead of the coin cells. But the first thing I did was remove the battery.

The trackball is a bit sticky. There are two posts that it rests on and they're slightly warn. I've given it a good cleaning but nothing helps. Is there a way to rotate the posts so that ball is resting on the unworn surfaces?

Is there anyway to open the lead acid battery? I would like to replace the contents with rechargables. Ideally these would charge from the existing circuitry but I've read that lead acid cells charge in a fundamentally different way from modern NiCads.

Finally, I have a modem card which I pulled from a (dead) PB140. It appears to be compatible with the PB100. Is this card of any use at all or is it just junk now in 2015?
Click to expand...
The display caps will probably help with contrast a bit, but since its such a pain, I don't plan on doing mine unless the display quits working entirely, lol

There should be a switch on the back side that sets it to draw on the coin-cell backup battery instead of the main battery, don't recall which setting is which on that toggle switch off hand.

For rebuilding the stock pack, that would be a major NO, I would NOT try to open that pack, unless you take serious precautions to deal with the lead and acid inside. I believe there ARE some lead acid cells that could be chained together and made to fit in the battery bay, but you would have to hunt around on that one. You would NOT be able to use any other battery chemistry and still charge it IN the laptop, I have mine setup to run off a pack of 6x AA NIMH cells, but I have to charge them in a separate charger, and honestly that's more hassle than its worth.

Modem could be of use, I still collect and use modems, I have an analog PBX phone system and a linux dial-in server setup in my home, so I can dial in to my linux box and get on lynx from all my vintage computers and terminals and browse the web, not terribly practical, but its fun to say you can, lol
 
RWallmow said:
The display caps will probably help with contrast a bit, but since its such a pain, I don't plan on doing mine unless the display quits working entirely, lol

There should be a switch on the back side that sets it to draw on the coin-cell backup battery instead of the main battery, don't recall which setting is which on that toggle switch off hand.

For rebuilding the stock pack, that would be a major NO, I would NOT try to open that pack, unless you take serious precautions to deal with the lead and acid inside. I believe there ARE some lead acid cells that could be chained together and made to fit in the battery bay, but you would have to hunt around on that one. You would NOT be able to use any other battery chemistry and still charge it IN the laptop, I have mine setup to run off a pack of 6x AA NIMH cells, but I have to charge them in a separate charger, and honestly that's more hassle than its worth.

Modem could be of use, I still collect and use modems, I have an analog PBX phone system and a linux dial-in server setup in my home, so I can dial in to my linux box and get on lynx from all my vintage computers and terminals and browse the web, not terribly practical, but its fun to say you can, lol
Click to expand...

I replaced all the caps at the back of the LCD. Definitely the hardest part of this repair. Alas it didn't have much (if any) effect.

Yes I'm going to leave the battery alone. As you say it's not worth it. I've already removed the sliding latch and may just attach it to the front of the case to hide the hole.

It doesn't sound like the modem board will be of much use to me hehe. I was hoping I could use it to transfer software in simpler way than the current HFSImport->Disk Image->MiniVMac->Floppy Image->dd->Floppy process I've been using.
 
You must log in or register to reply here.
Back
Top