A little over 3 years ago, I acquired a MessagePad 2100 (in my case, a 2000 model Apple upgraded to a 2100 noted by the MP2100 sticker near the interconnect port). A neat device, I was planning to actually use mine and track setlists for my favorite band when I went to live shows. Not long after my original acquisition post, it stopped turning on entirely.
Fast forward to several days ago, I finally decided to open it up and check out what it needed.
I tested several caps as well as the F1 fuse and found some caps to be shorted and the fuse had no continuity.
This was no biggie for me, as I know my way around a soldering iron (now anyways... last time I was really active here, I did not. Heh). The main issue was the significant lack of DIY'er documentation on the process for the 2x00 models. Anyways, through some rigorous Googling and consulting with some friend of a friend electrical engineers, I assembled what I believe to be an adequate all-cap replacement list for the 2x00 models.
For MP2x00 disassembly and reassembly, follow the guide below. You only need to go so far as having the motherboard out, you can leave the screen in unless you have additional repairs. Another thing not noted, it is substantially easier on yourself if you slide the battery terminal wires out of the housing rather than dangling. They're not too difficult to remove, if you've gotten this far you can figure it out.
https://www.pda-soft.de/hardware.html
The list of caps are as follows (From Mouser Electronics):
The supercap will need its legs bent to match the original. The fuse, being glass, was challenging to remove and I ended up bridging both ends with the iron to remove it. The new one is quite a bit larger, I was having a great deal of trouble finding a small enough one but this ended up working out fine. Just offset it from the pads a little bit so the solder can flow around the corner. The rest of the caps more or less fit like the originals. Some were slightly larger, some were slightly smaller. They all have good contact with the pads and solder joints. Be careful around the PCMCIA plastics, keep the hot air moving or you'll damage the plastics.
You can see here some damage to the PCB due to the fried cap. I removed the neighboring IC which also had soot and debris on the underside. I cleaned the area and the IC the best I could without damaging it further and then soldered back down the IC.
Following the reassembly guide, you can do your power on test when the guide tells you to. That's about the soonest I'd recommend plugging it back in. Get the board screwed back in and all the connectors plugged in first. You should hopefully once again have a working Newton!
Fast forward to several days ago, I finally decided to open it up and check out what it needed.
I tested several caps as well as the F1 fuse and found some caps to be shorted and the fuse had no continuity.
This was no biggie for me, as I know my way around a soldering iron (now anyways... last time I was really active here, I did not. Heh). The main issue was the significant lack of DIY'er documentation on the process for the 2x00 models. Anyways, through some rigorous Googling and consulting with some friend of a friend electrical engineers, I assembled what I believe to be an adequate all-cap replacement list for the 2x00 models.
For MP2x00 disassembly and reassembly, follow the guide below. You only need to go so far as having the motherboard out, you can leave the screen in unless you have additional repairs. Another thing not noted, it is substantially easier on yourself if you slide the battery terminal wires out of the housing rather than dangling. They're not too difficult to remove, if you've gotten this far you can figure it out.
https://www.pda-soft.de/hardware.html
The list of caps are as follows (From Mouser Electronics):
- TEN 1000uf 10v caps (upgraded to 16v)
- 6 on the CPU side and 4 on the PCMCIA side
- Mouser # 80-T495X107M16ATE100, Mfr Part # T495X107M016ATE1007280, Mfr KEMET
- Tantalum Solid SMD 16V 100uF
- TWO 330uf 6.3v caps (upgraded to 10v)
- Both of these are on the CPU side
- Mouser # 80-T520X337M10ATE025, Mfr Part # T520X337M010ATE0257280, Mfr KEMET
- Tantalum Polymer 10V 330uF
- TWO 47uf 16v caps (upgraded to 20v)
- Both of these are on the CPU side
- Mouser # 80-T491C476K20AT, Mfr Part # T491C476K020AT, Mfr KEMET
- Tantalum Solid SMD 20V 47uF
- TWO 33uf 20v caps (upgraded to 25v)
- Both of these are on the CPU side
- Mouser # 80-T491C336K025AT, Mfr Part # T491C336K025AT, Mfr KEMET
- Tantalum Solid SMD 25V 33uF
- TWO 10uf 16v caps (upgraded to 35v)
- 1 on the CPU side and 1 on the PCMCIA side
- Mouser # 80-T521B106M35ATE100, Mfr Part # T521B106M035ATE100, Mfr KEMET
- Tantalum Polymer 35V 10uF
- TWO 4.7uf 50v caps (not upgraded)
- Both of these are on the PCMCIA side
- Mouser # 80-T491D475M050, Mfr Part # T491D475M050AT, Mfr KEMET
- Tantalum Solid SMD 50V 4.7uF 2917 20% ESR=1.4ohms
- ONE 4.7uf 16v cap (upgraded to 25v)
- It is the only electrolytic canister so I left it alone. On the CPU side
- Mouser # 80-EDK475M025A9BAA, Mfr Part # EDK475M025A9BAA, Mfr KEMET
- Aluminum Electrolytic SMD 25V 4.7uF 20%
- THREE 3a littlefuse (the original was unknown so this was purely a guess)
- On the CPU side. Location F1. There is only one but get 3 just in case you muck it up
- Mouser # 576-0451003.MRL, Mfr Part # 0451003.MRL, Mfr Littelfuse
- Surface Mount Fuses 125VAC 3A .0227ohms 451 NANO2
- ONE 0.11F 5.5v supercapacitor (upgraded to 0.22f)
- On the CPU side. You can max out at .33F with these and it will still fit but .22F was easier to get
- Mouser # 504-KR-5R5H224-R, Mfr Part # KR 5R5H224 R, Mfr Eaton
- Supercapacitor .22F 5.5V EDLC Coin Cell HORZ
The supercap will need its legs bent to match the original. The fuse, being glass, was challenging to remove and I ended up bridging both ends with the iron to remove it. The new one is quite a bit larger, I was having a great deal of trouble finding a small enough one but this ended up working out fine. Just offset it from the pads a little bit so the solder can flow around the corner. The rest of the caps more or less fit like the originals. Some were slightly larger, some were slightly smaller. They all have good contact with the pads and solder joints. Be careful around the PCMCIA plastics, keep the hot air moving or you'll damage the plastics.
You can see here some damage to the PCB due to the fried cap. I removed the neighboring IC which also had soot and debris on the underside. I cleaned the area and the IC the best I could without damaging it further and then soldered back down the IC.
Following the reassembly guide, you can do your power on test when the guide tells you to. That's about the soonest I'd recommend plugging it back in. Get the board screwed back in and all the connectors plugged in first. You should hopefully once again have a working Newton!
