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electricmonk

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  1. electricmonk

    Powerbook 100 - DC power socket assembly missing a component

    Good news! Turns out I don't empty the bin nearly as often as I thought I did. Please excuse the terrible photo of this tiny thing - 5mm long, 4mm wide and 2mm high. Edit: It reads 0.94 uF so I guess it definitely is a capacitor. If anyone has any ideas as to what this part of the circuit does though I'd love to know. Also highly curious as to why this little cap would have fallen/blown off.
  2. Hi there, I have two Powerbook 100s. My plan is to make one really good one out of these two old beauties. I recapped one of them but it won't boot off my rebuilt battery. I have been suspicious of the appearance of the DC power socket for some time and then today while browsing online looking for info I noticed that my recapped logic board seems to be literally missing a piece. Please see the two images below of the complete and incomplete power socket assemblies: I opened up my non-recapped PB100 (left) and saw very clearly what was missing from the recapped PB100 (right). I'm hoping someone will be able to enlighten me as to what this missing piece is. At a guess after a bit of googling, could it be a multi-layer ceramic capacitor? Is this some kind of bridge circuit or something? It is with considerable regret that I realised once I looked at these side-by-side that the little brown component from the plug on the right was sitting on my desk for some months waiting for me to work out where it had come from before I swept it into the bin. The weird thing is that the powerbook with the missing component works very well running off mains - it doesn't run off battery though, and this may be connected. I have posted about my attempts to rebuild the battery in the powerbook 100 battery rebuild thread. Edit: updated theory as to what the component is after some googling
  3. electricmonk

    Powerbook 100 Battery Rebuild

    Hmm so this doesn’t appear to have fixed the problem. I can now read 6.73v across the battery terminals on the logic board with my 5 x AAA cells attached but it still won’t boot without the mains power adapter, and if I attach my benchtop power supply to the dummy battery it delivers zero current. The logic board can obviously READ the battery voltage because I no longer get the “No battery reserve power remains” error with my dummy battery, but if I pull the DC plug from the back it just turns off instantly rather than running off battery. I’m not entirely sure where to start measuring voltages on the board as I don’t want to short something out. I read 5.8v across the fuse. With no cells attached and with the power brick plugged in and battery bay switch pushed in I read 4.62v (jumps around a bit) across the battery terminals. Same reading with a dead battery attached. That seems very low for a charging voltage but I’m hesitant to draw too many conclusions from this because I ain’t no EE. Incidentally I get infinite ohms across the speaker so I think that explains why there is no sound. Audio works fine through the headphones. I’ve attached an image of the dummy battery brutally patched together with epoxy putty. As you can see the computer runs reasonably well off mains.
  4. electricmonk

    Powerbook 100 Battery Rebuild

    Anyway good news for anyone following this saga - sat down with a multimeter to investigate tonight and it was actually a mechanical problem. My disembowelled dummy battery wasn’t making contact with the positive and negative terminals at the same time - only one or the other depending on which way it was nudged. Because the end with the terminals was physically separate to the rest of the battery (just basically free floating) and there’s a bit of spare height up that end of the battery bay it just wasn’t pressing down hard enough. So that error message was, needless to say, coming up regardless of what kind of power source was connected to the dummy battery - the tech docs say the powerbook goes to sleep when the battery drops past 5.74v and it looks like you get the same error message whether it’s zero volts or 5.7v. The computer knows that the battery is inserted because it presses on a switch and if the voltage is below the lower threshold you get the error and it goes to sleep. So I’ve done a quick and dirty job of rebuilding the battery pack by tacking the end back on with superglue and then filling in the jagged cut with epoxy putty. That should be nice and solid when it dries and the battery should exert sufficient force on the terminals to make good contact.
  5. electricmonk

    Powerbook 100 Battery Rebuild

    I understood you - it just strikes me that you would have to either have a cable travelling from the battery bay to the outside of the computer and snaking round the back to the power plug... or you’d have to cobble together some means of switching between the “Internal thinpack” and the mains power adapter. I suppose if you just disconnected the internal battery cells you could run off mains but if the battery and the AC were connected at the same time would that be bad? I suppose they’d be running in parallel.
  6. electricmonk

    Powerbook 100 Battery Rebuild

    Further on that subject, @Trash80toHP_Mini, the sensor mechanism is just a switch that gets pressed when the battery gets shoved in... presumably the laptop measures the voltage of the battery but I don't see how that would make a difference. Maybe I'll scrutinise that Macintosh portable thread again and try and figure it out. Found the developer notes here. Here goes nothing: http://powerbook.micahgartman.com/ The PB100 developer notes say that the powerbook 100 power manager is identical to that of the portable which is described in this document: https://macintoshgarden.org/apps/apple-guide-the-macintosh-family-hardware This may also be useful. Wish me luck https://macintoshgarden.org/apps/apple-mac-technical-reference-and-repair-manuals
  7. electricmonk

    Powerbook 100 Battery Rebuild

    That is a good idea although you would need some means of turning off the internal battery to allow you to run off mains when desired. Thing is this problem does have a solution and it will be a logical one, it's just a question of figuring it out. Unfortunately one would need a non-dead PB100 battery to test whether the issue is the logic board or the battery itself, and those aren't exactly easy to come by. I'm guessing it is the logic board itself - the thing just doesn't boot when only the dummy battery is connected. I suppose I could recap my spare logic board and try that. Quite a lot of effort though.
  8. electricmonk

    Powerbook 100 Battery Rebuild

    Well, I was wrong. I had actually re-installed the battery terminals. Don't understand what the problem is - when I attach the benchtop power supply, the bank of 5 x AAA batteries or my spare very dead lead-acid battery to the terminals the same message comes up: "No battery reserve power remains. The Macintosh will go to sleep within 10 seconds to preserve the contents of memory. Good Night." The message doesn't appear when running under AC power only, but it does appear if running on AC power with the "battery" connected. There's a reference to this error message in a thread about a Macintosh portable here. I know that the PB100 is just a miniaturised portable but the solution they reached in that thread was achieved by careful testing and I'm sure there are any number of reasons why that error message would come up. Hmm. It is a bit disconcerting that there are several errors in the maccaps PB100 reference page with respect to capacitance & voltage values. I was reasonably careful to go by what was printed on the capacitors rather than that page but maybe I missed something. It all works fine although the sound does appear to have stopped working which could possibly be connected - or not.
  9. Any progress on this one? Cracker of a thread.
  10. electricmonk

    Powerbook 100 Battery Rebuild

    Well, @elemenoh, I decided to take a few steps forward in my little project. I don't have a 3d printer to fabricate a dummy battery but I do have a few dead Powerbook 100 lead acid batteries so I decided to cannibalise one to make a NiMh battery pack - main priority is that the powerbook looks legit from the outside. Couldn't find any images online of what's inside the pack so decided to break out the Dremel with the reinforced cutting wheel and dissect an original powerbook 100 battery for the benefit of mankind. It appears I cut into the cells themselves rather than cutting off the top. I wondered why it smelt like vinegar and my nose was tingling. Never mind. I would have had to cut it open to remove the innards anyway. I pulled out the lead plates & totally dried-up matting and chucked them in a bucket of baking soda solution which proceeded to fizz a bit. Now I have three empty cells and the top section of the battery completely loose. There’s a different, entirely unmolested PB100 battery in the background just to confuse you. Turns out there's actually a plastic cap on the top. When you crack it open you see three rubber caps sealing up the three cells (one is missing in photos), a couple of wires going to the contacts and a thermistor or whatever it's called - a thing that cuts off the current if the temp gets too high. With those little holes covered with removable rubber caps you could theoretically try to restore the lead acid cells to semi-working order with Epsom salts I guess. I didn’t want to because I doubt that they would ever hold much charge again even if you did manage to get them working again. My plan from here was to cut those wires, solder longer wires to them, feed them through the cell ports and attach them to a AAA battery pack. I will short one of the battery slots to make a 5-battery pack. 5 x NiMh batteries at 1.45V start voltage per cell means just over 7.25 volts. Actual measured start voltage once NiMh batteries were charged was just over 7 volts which seems reasonable if the range of the Lead Acid battery was 6.5-5.5 volts. I hacked a hole in the battery to install the battery packs, fed the wires through, inserted the bisected battery into the battery into the slot and hooked the wires up to a bench power supply set to 7V/1A in order to test it. I had to reset the powerbook power manager (http://www.jacsoft.co.nz/Tech_Notes/PP_Manage.shtml) to get it working otherwise I kept getting a "there is no battery reserve" error. But then it still wouldn’t boot from the “battery” power, only from the AC adapter! It was at this point I realised I had forgotten to re-install the battery terminals so there was an air gap. Oops. Note the 40V 3A diode to stop the laptop from trying to charge the power supply. Will install this in my rebuilt/modded battery pack. Oh well, I'll have to resume work on this again later in the week. I’m keen to see if it works. Note that this powerbook has a SCSI2SD installed and I have left off the palm rests for testing. So far so good though. I totally recapped it and the removal of surface mount components was greatly aided by my nice new hot air rework station. Accidentally melted one of the plastic ribbon cable sockets a bit when soldering a new tantalum cap nearby but the socket still works thankfully. The socket only latches on one side now but it doesn’t seem to have any great inclination to work itself free - will tape it up with electrical tape when I’m done. The screen looks great but it has a few subtle dark lines here and there so I'll need to recap it at some point to see if that improves things. May have to actually learn how to solder new surface mount components for that. P.S. sorry for the messy desk
  11. electricmonk

    Powerbook 100 Battery Rebuild

    I thought I'd resurrect this old thread rather than starting a new one, hope that's OK. I have a plan to cannibalise a PB100 battery pack so that 5 x 1.2V AAA Eneloops can be clicked in and out and recharged using an external charger. This would permit carrying extra AAA cells in the field (for those times when you take your 28 year old Powerbook out on field assignments). Apparently Eneloops (NiMh) have a nominal voltage of 1.2V, but actually they start out at 1.45v (x 5 = 7.25v) and then settle down to 1.3v (6.5v) which would seem to mirror the range seen out there in the wild - if the original battery contained 3 x 2V cells, then presumably one can extrapolate from this discharge graph for lead acid batteries similar behaviour for 2v cells. If roughly 6.5v-5.5v is the range for the SLA batteries and the Nominal 7.2V 3rd party NiMh battery that aplmak disassembled apparently also works fine then it sounds like 5 x Eneloops (nominal 6v) would work just fine. In fact judging from the fact that the 3rd party battery pack contained 6 x nominal 1.2V NiMh cells it looks like I could install 6 Eneloops and get away with it but the idea makes me nervous. What do you guys reckon? I expect I would have to look into the diode installation idea to prevent the SLA charger from destroying the NiMh Eneloops. That said if there were original 3rd party powerbook batteries available which used NiMh then maybe the internal charging circuitry works fine with NiMh?
  12. electricmonk

    Macintosh Classic - no sound after recapping analog board

    Hi everyone, thanks for your help. I cracked open the HDD and put electrical tape on the sticky rubber bumpers and now the computer is working well. Sound works, HDD works, recap of AB and LB seems to be holding up. The 5V pin on the floppy port varies by 0.02V from time to time - anyone know if this is acceptable? Perhaps if I replace those diodes that will fix it. I'll get a SCSI2SD or a FloppyEMU at some point down the track so I don't have to rely on this HDD although I've read that they are reasonably robust even after you've opened them up. The screen still wobbles sometimes with hard drive access but not nearly as much as it used to. Does anyone know if some wobble with disk access is acceptable and/or expected? As an aside, I accidentally dropped a pair of pliers on the back of the CRT and consequently necked it (dumb!) but thankfully there's a guy in my city who had a few Compact Mac CRTs for sale - now I have a newer CRT from a Classic II installed (with the yoke from this Classic I) and after some basic adjustments it's actually a lot brighter than it was before... so I'll call this clutching victory from the jaws of self-inflicted defeat...
  13. electricmonk

    Macintosh Classic - no sound after recapping analog board

    Oh dear, turns out that one of my solder joints on the logic board had broken free. Thanks for the tip-off that it was probably a logic board problem! I redid the solder joints on the LB and the sound is working again. No luck with the hard drive yet, it's a Quantum 52 which doesn't bode well I suppose. Next step is to get another SCSI drive to test. I put the Classic on its side and tried to boot it because I thought that might free up the heads but no dice.
  14. electricmonk

    Macintosh Classic - no sound after recapping analog board

    Thanks for your suggestions guys, I'll check the diodes, I'll check whether the voltage stays constant and I'll check the polarity of the capacitors. If sound is a logic board problem it does seem odd to me that the sound was working well after I recapped the LB but stopped working after I recapped the AB. I'll let you know how it all goes.
  15. Hi all, I've been fiddling around with this Mac Classic to try to bring it back to life. I washed the motherboard and it started working again so I figured recapping the MB was the next step. So the other day I finally found some time and I recapped the MB. All was working well, it's got some goofy golf game on there from the previous owner, good times. The image on the screen was shuddering in time with hard drive access though so I figured I should recap the analog board - although now I kind of wish I hadn't, as will be explained later. I decided to replace the following as recommended by this page http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/1990/10/15_Macintosh_Classic_Analog_Board.html CP2 CP6 CP7 CP8 CP9 CP10 CP12 CP36 All of the above had leaked so I cleaned off the residue underneath once they were removed with isopropyl alcohol. I also replaced CP11 because there was gunk around it like it had leaked. So I replaced all those, and now there is no sound and the screen still flickers. Then the hard drive stopped being recognised. I read somewhere that it's good to adjust the voltage after replacing AB caps so I did that. The 5v rail gave 4.79 so I adjusted the trimpot to 5V and the hard drive spun up again. Still no sound though, and now the hard drive has stopped being recognised again. Any thoughts on the next step? Thanks for your time.
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