Contributed Articles

Contents

1. Opening your PowerBook 100
2. PowerBook 100 Battery Insights
3. Rejeuvenating Dead Batteries
4. Refurbishing Dead Batteries
5. Broken power cable socket on motherboard

1. Opening your PowerBook 100

contributed by Tim Steele

Warning

The PowerBook 100 is extremely fragile internally, and must be treated with extreme care to avoid an expensive repair bill. If you're not sure what you're doing, don't do it! If you break it, it's your responsibility!
You MUST back up the RAM disk as this will be lost. You are strongly recommended to back up the hard disk as well. Memory and disk drives are very fragile and must not be removed from their anti-static packaging until you are grounded via an anti-static mat and wristband.
DO NOT attempt to reinsert batteries until the machine is fully assembled and screwed together. Doing so can easily cause a short which will blow the 5A fuse on the motherboard. This fuse is soldered on and tricky to replace.
You will need: - Static mat with wristband and earth connection - Clean tea- towel - Jeweller's flat bladed screwdriver, smallest available - 45 degree point Philips screwdriver - Small flat bladed screwdriver
Notes on removing flat cables from sockets:
The socket is in two parts which are pushed together to lock the cable in place. To remove the cable, use your fingernails to pull on the two lugs at either side of the socket (in the direction of the cable, not upwards) with equal force until it clicks out about 1-2mm. The cable may now be removed with an even pull. When inserting, make sure the end of the cable goes all the way into the socket and support it so that it does not buckle.

PowerBook Disassembly

Disconnect your PB100 from all peripherals, power supply etc. Put your PB on a static mat. Wire the mat to mains earth. Put on the mat's wristband to earth yourself. (The general practice is to have a 1 megohm resistor between the earth and mat/wrist/or anything one might touch. This is to prevent a potentially fatal current should you touch a live mains circuit [not a problem inside the PB100, but we don't want recommend a bad practice here!])
Close and latch the PB. Remove the lithium batteries and put aside. Remove the lead acid battery (use thumbnail in gap) and put aside. Turn PB upside down. Gently prise out the three round feet with the jeweller's screwdriver without damaging them. Put aside. Unscrew the three long Philips screws which were under the feet. Put aside. Turn PB over.
Release latch and gently and slowly lift up the display. When it is clear of the body, lay it down screen up behind the machine being extremely careful not to stress the wires.
Lay the tea towel over the display. Disengage the palm rest from the front of the case and the keyboard. Remove the palm rest and put it aside. Flip the keyboard over and lay it upside down on the tea towel. Be very careful not to stress the flat cables.

Installing a New Memory Module

If there is a memory module already installed, it must be removed first. To remove the old module, it must be levered out very carefully using a wooden or plastic spatula placed between the memory module and the motherboard. Do not use a screwdriver.
Remove the new memory module from its anti-static bag and seal the old module (if any) inside it for safe keeping. Check the pins on the motherboard connector to ensure they are straight. Line the new module up with the connector (at the left hand end of the keyboard area). Press down firmly on the connector site until it is fully seated.

Upgrading the Disk Drive

The brackets and screws for the Apple 20MB and 40MB hard drives are NOT the same. Make sure you have the right brackets and screws before proceeding. Apple part numbers are as follows

Gently lift up the metal shield to reveal the flat cable connector. Unlock and remove the flat cable (see above).
The hard drive has two spring steel brackets attached to it which hold it in place. Use a small flatbladed screwdriver to bend the right hand ends of the brackets towards the drive, while lifting the right hand end of the drive up slightly with your fingertips. The result should be that the brackets disengage from under the protrusions in the lower case moulding. When both brackets are disengaged, lift the right hand end of the drive up and out; the left hand ends of the brackets should slide out from their sockets and the whole drive should lift out.
Very gently prise the SCSI connector away from the drive by inserting a small flatbladed screwdriver between the black plastic connector on the cable and the black plastic block on the drive. Do not attempt to pull it off using the cable, which will probably be damaged.
Remove the new drive from its anti-static and anti-vibration packaging and pack the old drive in it for safe keeping. Fit the new brackets and screws to the new drive. Be very careful to use the proper screws.
Installing the new drive is fairly obvious once you have removed the old one. Be sure to fully insert the flat cable with the motherboard connector held fully open, then fully lock the motherboard connector by pressing on both ends simultaneously until the two halves are at the same height. Do not put any pressure on the flat cable itself

Reassembly

Carefully engage the palm rest. If the drive has been changed, make sure the palm rest goes into place properly; if the drive has not been installed correctly it will flex the plastic upwards in the drive area; this must be put right before the unit can be reassembled.
Very carefully engage the keyboard without stressing the flat cables. Hook the two tabs at the front under the palm rest. Remove the tea towel, then carefully engage the display with the lower half. When this is done, close and latch the display half. Turn the unit over and reinsert the screws. Reinsert the three feet and make sure they are secure.
Reinsert the lead acid battery followed by the three lithium batteries, which should be carefully polished beforehand on the tea towel to remove any contamination from your fingers. Make very sure you put the lithium batteries in the right way round - if you insert them upside down you will destroy your PowerBook.

Testing

Power the machine up and see if it boots. If you have replaced the drive you may need to install a system on it using the floppies provided with your PowerBook.
Be sure to power off before connecting the floppy drive. Check "About this Macintosh..." on the File menu and see if the Total Memory corresponds with what you have installed.

Note: See also article 5 below which focusses on replacing the main fuse and resoldering the power connector socket

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2. PowerBook 100 Battery Insights

contributed by Don Edberg

PB100 Battery Drain Measurements

I have done a few measurements on how the Apple AC adaptor charges the PB100 batteries, and now I think I understand why their life is so short. Most gel-cell (gelled electrolyte lead- acid batteries) will give from 100-500 discharge cycles if properly maintained, but the PB100 batteries don't seem to last more than a year at the most after experiencing much less usage. The work was done to understand why the short lifetime occurs.
The Apple AC adaptor supplied with the PB100 maintains a voltage of approximately 7.70 to 7.80 volts regardless of the load. This is somewhat higher than the 6.9 to 7.2 volts recommended for charging or "floating" a three-cell lead-acid gel cell by manufacturers. To see what was actually applied to the battery, I fully charged my PB100 battery and put a current and voltage meter in the circuit (PB100 and Apple AC adapter).
With the machine off, the current slowly tapered to about 0.027 A at full charge. Then, I started up the PB100 and measured various current drains, with the assumption that the battery would not be using most of this since it was already charged. For reference, the hard disk is a 120 Mb Quantum, and all measurements were taken with the machine running at 16 MHz. Here are the measurements I obtained

By subtracting the battery removed measurements from the battery installed ones, we can conclude that the charged battery only consumes 0.05 - 0.07 A or so. But more importantly, subtraction of the backlighting numbers indicates that the backlighting consumes far more current - about twice as much - than does the spinning disk (0.36-0.38 A vs. 0.17-0.18 A). So one moral of this study is to not use backlighting when you are trying to conserve batteries, since it consumes more than twice the power of the spinning hard drive. It doesn't hurt to not use a hard drive either, though. If you can configure a RAM disk it will help prolong usage on batteries.
Then I disconnected from the AC adaptor and ran off battery for about 100 minutes, until the first warning came on. I reconnected the adaptor and made more measurements. The current flow, with the machine turned off, is 1.94 A. This is about 8 times the "C/10" (0.23 A charge rate, meaning the nominal rate to charge the battery in 10 hours), so it brings the battery charge back rapidly, in not much more than an hour. But at what cost? I suspect battery life.
Because the charged current drain is low, the only other place that can do damage is this high initial charge rate. So, my guess is that we want to lower it to make the batteries last longer (assuming that you can wait longer for the battery to be charged, anyway). This can be done one of two ways: change charge procedures, or get a different charger.
If you startup your machine after you put it on charge, and turn backlighting up to full, the machine itself will consume about half the current, so the battery charge rate will be reduced and it may live longer. It will also take longer to charge, but most of the time we let it sit overnight anyway, or use it while plugged in.
The other thing to do is get a lower rate charger. I noticed that one outfit is advertising a lightweight ac adaptor in MacWeek that will increase the battery life but not fully power the machine, for about $60(?). That is exactly what is needed. I happened to find a six-cell 0.4 A Ni-Cd battery charger in Radio Shack for $2 (Cat. No. 23-231A, discontinued) that will do the same thing at a substantially cheaper cost, but one has to remember to disconnect it after 5-6 hours because gel cells should be charged at constant voltage, not constant current. Presumably the replacement unit for this charger won't have that particular problem. So, if you wish to prolong your PB100 battery life, I believe that you should charge with everything (disk drive, backlight) on and running. Or else, get a lower rate charger.
I am pretty sure that Apple chose to use the high charge currents to get a rapid charge time, but a byproduct of this choice might be reduced battery lifetime which in turn means more battery sales too. I have noticed similar reduced-life problems with gel- cell batteries for camcorders and such that are also charged at a very high rate, so I feel pretty confident that the high charge rate is the culprit. Are we really in that much of a hurry?

PB100 Battery Booster  

One day I attended a meeting where I took notes for a 4-hour stretch, taking nine pages of notes in MS Word. I brought along both a fully-charged PB100 battery and a radio-controlled car battery with an adaptor cord. The RC car battery has six Ni-Cd cells (7.2 volts nominal, 1300 mAH), and weighs about 10 oz. I had previously wired a custom adaptor cord to connect the RC car battery to the charging jack of the PB.
During the note-taking I watched the battery indicator shown by Norton Essentials. Whenever the reading dropped below 60 minutes, I plugged in the RC car battery for a few minutes, which appeared to "top off" the internal lead-acid battery, and then I unplugged it.
During the four hours, I had the backlight turned off, but at the end of the meeting I still had 45 minutes indicated on the internal battery, and I don't know how much remained in the RC car battery.
This might be a solution to battery life problems during long airline flights or increasing the usage between charges. If you'd like to try this, let me know and I'll give you the details.

Another way to improve PB100 Battery life

Since the backlight makes up the largest portion of the PB100 battery drain, I figured that turning it off will prolong battery life. This is great if you sit in a well-lit place, but what about the airliner at night with its overhead lights poorly aimed?
I carry a flashlight for emergency lighting on business travel. It is a Pelican VersaLite with three different hooks for clipping onto different things. I got the 'bright' (pun intended) idea of clipping it onto my eyeglasses and aiming it where my eyes were looking.
Well, this idea worked great! Without the constant current drain of the backlighting, my PB100 went the entire duration of a three-hour flight, and Edison indicated that there was still over an hour of life left. Sure, I got some funny looks from passengers and flight attendants, but it's worth it to double your battery life, at the cost of only two AA penlight batteries.

In conclusion

I hope the battery measurements and speculation that I made above are useful to other PB100 owners.

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3. Rejeuvenating Dead Batteries

contributed by Dave Beane

Shortly before I got my PB100, I had a 1 KW UPS that was not working due to its (lead-acid) batteries being dead and not holding a charge. I had had some dealings with a battery specialist, however, who told me that lead-acid batteries can frequently (about 85% of the time, he said) be "rejuvenated" by passing a trickle charge of about ten milliamps through them for several days (he said "about four or five days".) The problem, as he explained it to me, is that sulphates build up on the lead plates, reducing the efficiency with which the battery operates. This can be remedied, he told me, by trickle-charging them as described above, which breaks up the sulphates on the plates, returning the battery to its original condition. Hearing this good news, I took him the batteries from my UPS, and he trickle-charged them in the above fashion for four days. At that point they once again held a full charge, and when installed in my UPS, functioned normally.

Then I got my PB100. The battery it came with was nearly dead, and I convinced the dealer who sold it to me to replace it with a new battery, which lasted about a year before it would finally not hold my PB100 up for more than a few seconds. A phone call to the battery specialist refreshed my understanding of the reconditioning process, and I set out to try it for myself on my 100's dead battery. What I eventually came up with was an AC adapter for a calculator (I think) which had the proper voltage (it is rated 6 VDC at 600 mA), and which I was able to connect to my PB100 battery using a spare connector and some big alligator clips. When this AC adapter was connected to my PB100 battery, it managed to push a current of 12 milliamps through it. I connected it, and let it sit for four days (I was going into DT's without my PowerBook.)

IT WORKED. After four days, I put the battery back into my PB100, and saw that it held it up just as it did when the battery was brand new. (One hour while using the hard drive constantly, or four hours using the RAM disk as my startup drive and holding my application and documents.) I was ecstatic.

Another year went by, and the battery again needed reconditioning. I again hooked it up and let it set. This time, after four days, the battery was not completely rejuvenated. In fact, as I now write this, it only holds my PB100 up for a few minutes (which is better than it was). I have yet to retry the process, since it requires that I leave my PB unused for a week or so (very hard to do.) If there is enough interest in this group, I will try it again, and report the results. I know it worked once, and it may just take longer with an older battery.

This is not the end of this tale, at least not yet. In the interim following my first success I tried to recondition five very old PB100 batteries for someone who had several PB100's, and failed miserably. These batteries were several years old, and appeared to be shorted internally (though I don't know by what process). They would not respond in any fashion. It is because of these failures that I have been reluctant to share this with anyone, as I did not want to get their hopes up. For those of you who have very old batteries, I don't know what to tell you. They might not be hopeless, and I imagine that each circumstance will be unique. For the person who has a battery at the end of it's first lifetime, or that still lasts a short time before becoming exhausted, this process might help you squeeze some more life out of it.

If you want to try it for yourself, do as I did. Visit garage sales, and buy old AC adapters that are rated at roughly 6 volts DC (7 volts might work as well, although it will probably pump more current through your battery, which doesn't work as well.) Obtain a cheap digital multimeter, and measure how much current flows when the adapter is hooked up to the battery. (For those without a background in electronics, you will need to determine which of the AC adapter's wires is positive and which is negative, by touching each of the multimeters leads to one of the AC adapter's wires while the AC adapter is plugged in. When the multimeter reads a negative number, the red multimeter lead is touching the negative wire from the AC adapter. Once you have determined this, hook the negative lead from the AC adapter to the negative (-) terminal of the battery, then hook the black multimeter lead to the positive terminal. With the multimeter turned on and set to DC current and 20 mA, hook the red multimeter lead to the positive terminal of the AC adapter. When you are in this configuration (with the AC adapter plugged into the wall) you should have a positive two digit number on the multimeter's display. This is the number of milliamps flowing through the battery (ideally, it should be about 10. Much more than this will simply heat the battery without affecting it, just like the PB100 adapter does). When you are ready to leave the battery for several days, hook the negative wire from the AC adapter to the negative (-) battery terminal, and the positive wire to the positive (+) battery terminal. This is the normal charging configuration.  

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4. Refurbishing Dead Batteries

contributed by James MacPhail

Rather than try to revive a dead battery one may try to replace the gel-cells, either by opening the original Apple battery and replacing its contents or building a home-made contraption. The first option is not without hazard as the Apple lead batteries are just plastic shells containing the lead/electrolyte, with no internal containment for the chemicals: the case is the battery, so to speak. Opening the battery gets you a lead powder or paste mess. The alternative is to custom-build a container with contacts and latching mechanism, which is not that simple either. Manuel Mejia Jr. has written a column about this on the Lowend End Mac site, involving some serious carpentry. As far as the second option is concerned, this is what James MacPhail has to say about it.
'I have been experimenting with a PowerSonic PS-605 battery. It costs about $14 each in small quantities (1) and comes with wire leads. It is a 6V 0.5 Amp Hour sealed lead acid battery, measuring about 2.25" x 2" x 0.5" (about 57 x 50 x 13 mm), small enough to put up to 4 in the PB100 battery slot. (It is the only off-the-shelf SLA battery I can find that will fit in the battery slot.) The one I have can deliver a maximum of 0.5 Amps; since the PB100 draws 1 Amp on a regular basis, the minimum PS-605 count would be 2; although 3 may be required to handle startup current, and 4 would certainly result in less stress on the batteries. At 0.5 AHr each, 4 of these wired in parallel would give 2 AHr; the original Apple PB100 battery had a rating of 2.5 AHr (I believe that was a rather optimistic rating, but it may have been the "20 hour" discharge capacity).
How much engineering needs to be done and how serious an option is that for a non-engineer? There seems to be three engineering problems: 1) holding the batteries together, 2) holding them in the PB100, 3) connecting them to the PB100. No. 1 can be satisfied with RTV silicone (or some glue). Although I haven't tried it (not having 4 PS-605s), I expect that 2 & 3 can be satisfied by using the ends of an old Apple battery to provide the contacts and slide latch, and then fill up the excess space as necessary. This provides a bit of a challenge, however I would suggest that any hobbyist with a hacksaw, soldering iron, glue gun, and the ability and confidence to change hard disks in a PB100 will be able to do it, and quite easily once someone has developed a technique. If this procedure works easily enough, I expect there will be enough folks around with the ability to build these for next to nothing + parts. I suppose I should point out that there is a bit of a hazard inside SLA batteries, so they want to be disassembled carefully (e.g. with gloves and goggles), and the contents properly disposed of via a lead-acid battery recyling facility. It does seem that an external battery is the price/performance winner, so the question that remains is: is a viable internal battery worth its cost and trouble?'

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5. Broken power cable socket on motherboard

The PB 100 has got one potentially serious flaw. After a time, the power connector socket on the back of many PB 100s becomes fragile and develops open circuits, due to weak solder joints. Sometimes the fuse on the motherboard also blows. In either case, a new battery doesn't help, and the computer seems DOA. Apple authorized service will refuse to do board-level repairs, and the cost of an installed new motherboard can be several hundred dollars, more than the used value of the entire PB 100 ($300-400).

But, all is not lost. Rather than junking the unit, almost anyone who is handy with a soldering iron can attempt the fix (although I AM NOT RESPONSIBLE FOR ANY DAMAGE YOU MAY INFLICT ON YOUR MAC!). The most difficult step is taking the unit apart - the actual repair is easy. Here are the steps that worked for me:

1) Remove the main battery, the PRAM batteries, and turn off the power switch at the back right.

2) Turn over the PB and pry out the 3 rear round rubber feet, which hide the screws that attach the display.

3) Open the PB lid halfway so you can get a good grip on the display and then remove the 3 screws - make sure that when the display comes off, it does not fall away from the base and pull on the wires between the two parts.

4) Lay the display slowly back on the table and carefully pull straight up on the black connector that connects the display wiring to the motherboard. Note the left-right orientation for reconnection later.

5) The keyboard can now be tilted up slightly and slid 1/8 inch away from you, and then the front edge will be free of the upper case. It can then be rotated up vertically, and you will see the two flat cable connectors that attach it to the motherboard. The connectors are a special type that pinch down on the flat cable - THE CONNECTORS DO NOT COME FREE FROM THE MOTHERBOARD! (I broke one finding this out.......). Instead, the top of these connectors can be popped up about 1/16 inch, which relieves the pinching pressure they exert on the flat cable. Then, the flat cable can be pulled straight up and out of the connectors. Again, DO NOT TRY TO REMOVE THE CONNECTOR, OR THE TOP OF THE CONNECTOR. Just snap the top part up a little on the left and right sides, and then the flat cable can be pulled out. Release both flat cables this way, and the keyboard is free.

6) The rest of the case top can be removed by first lifting up on the rear arms, and then lifting straight up.

7) The trackball unit is attached to the motherboard by a single keyed connector - the male part of the connector can be pulled straight up, and the then trackball sub-board comes out easily - no screws.

8) The hard drive connector is under a foil flap that can be temporarily lifted up. The cable is another, larger flat cable like the display. Use the same approach - lift up the top of the black connector a little, so the flat cable can slide out of the connector.

9) There is a foil shroud that sits over the modem area - lift the back of the shroud, and then rotate it vertically toward you so it can be slipped off the little fingers that hold it near the battery area.

10) Now, except for 5 tiny screws, the motherboard is free. There are 4 brass screws toward the front of the motherboard. The two on the right also hold the battery terminals in place, but if you don't tilt the case bottom, there is no need to remove the terminals - just the screws. The fifth screw is black and is at the back left corner of the motherboard, next to the post holding the PRAM battery connector. It is under a clear plastic flap. Using your delicate surgeon's fingers, it will come out easily.

11) Now you can lift up on the front edge of the motherboard, and rock the board up and out, so that the main connectors (serial, SCSI, etc.) at the rear come free from their plastic cutouts.

12) Relax - the hard part is over.

13) To see whether you have the loose charger cable connector problem, find the female black power connector at the back right corner of the motherboard. Flip the board over and find the two solder points that attach the connector to the board. With good eyes, you may be able to see tiny cracks at the base of the solder dimple around the wires - this is the cause of the poor connection. I had to use a magnifying glass to see the hairline breaks. Even if you can't see any cracks, reheat these two solder joints with a fine point soldering iron until the solder reflows - this may cure your troubles. While you are inside, also check the fuse with a continuity tester - it is visible on the area of the board behind the battery.

14) Put it all back together in reverse order. Make sure the three flat cables are seated deeply in the pinch-style connectors before you push down on the top part of the connectors to lock the cables in place.

15) Try it out. After doing this, my PB 100 was miraculously cured - it began charging again, the battery held charges for longer periods, and I can now use it dependably with the charger unit providing the power. Prior to the resoldering, even operating the PB 100 using wall current was undependable.

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