In the next post, I'll post photos of my progress with the recapping itself, since I'd like to know what the experts think I could improve upon in terms of my soldering.
Original condition prior to repairs, but after battery replacement:
Repairs made so far:
Current condition after the repairs:
Question related to the diodes: I noticed that the positive wire leading from the battery-door switch to the positive terminal of the 9V backup battery had no continuity, so I cut off the black plastic that was wrapped around one section of the wire. Underneath that plastic I found two 1N5817 20V @ 1A diodes in series, but the connection between them was broken. I couldn't find 1N5817 diodes at Radio Shack so I temporarily picked up a couple of 1N4001 50V @ 1A diodes. I am guessing that the two 1N5817 diodes are simply there to prevent damage to the circuits in case the 9V battery is installed backwards -- is this correct? I see that the voltage drop from the two 1N4001's is higher, so if anything, it shouldn't damage the computer to have those on there instead of the 1N5817's, and they would offer more protection. But can anyone tell me if the 1N4001's are an acceptable replacement? I can easily order 1N5817's from Digi-Key but if the 1N4001's are just as good, then I'll just run with those.
Question related to the battery wiring and switch: I am a bit puzzled by the wiring for battery power connections in this machine.
-=DG=-
PS -- I will post the photos later today
Original condition prior to repairs, but after battery replacement:
- would only boot from a floppy or external drive
- would not start up or run from a battery, only from an external power supply (24W version from PowerBook 165C)
- speaker will not work
- battery will not charge
Repairs made so far:
- replaced innards of original battery with a PowerSonic PSG-650 (it fits perfectly inside the shell of the old battery)
- removed all radial through-hole caps and replaced with ones from Radio Shack (fatter and with higher voltage ratings/lower temperature ratings, but still fit OK)
- removed all aluminum electrolytic caps and replaced with tantalums ordered through trag (Jeff Walther)
- replaced the hard drive with a similar model (Dylan swapped the PCB from the original dead drive to a working other drive from a desktop Mac, and it worked... thanks Dylan!!)
- cleaned motherboard as much as possible with alcohol & swabs, also CyberClean putty (not sure if OK to use, but it did pick up a lot of crud from the board and didn't seem to damage it!)
- removed broken diodes from positive wire of 9V battery (see issues below)
Current condition after the repairs:
- after capacitor replacement, speaker works again!
- still won't boot up or run from a fresh battery, which tests at 6.45V (I may have botched part of the recapping, see next post)
- starts up from internal drive with the (7.5V @ 3A) PowerBook 165c adapter
- after booting, in the Battery desk accessory the indicator is about 1/6th of the way full (just past the initial little line indicating reserve power)
Question related to the diodes: I noticed that the positive wire leading from the battery-door switch to the positive terminal of the 9V backup battery had no continuity, so I cut off the black plastic that was wrapped around one section of the wire. Underneath that plastic I found two 1N5817 20V @ 1A diodes in series, but the connection between them was broken. I couldn't find 1N5817 diodes at Radio Shack so I temporarily picked up a couple of 1N4001 50V @ 1A diodes. I am guessing that the two 1N5817 diodes are simply there to prevent damage to the circuits in case the 9V battery is installed backwards -- is this correct? I see that the voltage drop from the two 1N4001's is higher, so if anything, it shouldn't damage the computer to have those on there instead of the 1N5817's, and they would offer more protection. But can anyone tell me if the 1N4001's are an acceptable replacement? I can easily order 1N5817's from Digi-Key but if the 1N4001's are just as good, then I'll just run with those.
Question related to the battery wiring and switch: I am a bit puzzled by the wiring for battery power connections in this machine.
- a thin black wire goes from the negative terminal of the 9V backup battery, then merges with a thick black wire that connects to the negative terminal of the 6V main battery; then both wires run down to the four-pin motherboard power plug (the thin one goes on the left and the thick one goes on the right, but they both test as being at the same voltage in all situations)
- a thin red positive wire runs from the 9V battery's positive terminal through two diodes and into the first terminal on the three-terminal switch that is activated by the placement of the battery door; meanwhile a thick red wire runs from the positive terminal of the 6V main battery into the second terminal on the same switch; lastly the third terminal on the switch feeds the thick/thin red wire pair that runs down to the four-pin motherboard power plug
- when the battery door is in place, the voltage across any red-black wire pair at the four-pin motherboard plug is 6.45V (same voltage as main battery)
- when the battery door is removed, the voltage across any red-black wire pair at the four-pin motherboard plug is 8.45V (same voltage as 9V battery minus the voltage drop from the new diodes I put in)
-=DG=-
PS -- I will post the photos later today