In part one I did some testing of this laptop and now the Canon NoteJet II came back out because the built-in printer still wasn’t working. The computer side did boot, but the display took a long time to warm up, and turning on the printer caused a big current spike that reset the machine. I went ahead and replaced the temporary drilled power connector with proper adapters so I could keep testing it more cleanly.
Getting inside it wasn’t especially simple. I removed the chassis screws, including the hidden ones under the keyboard and paper tray, pulled the hard drive, and then worked through a stack of flat flex cables before the two halves would separate. Once it was open, I found corrosion on a shielded area, plus a loose piece of cushioning that had fallen into the printer gear train.
I cleaned the corrosion with isopropyl alcohol, used vinegar to neutralize any remaining residue, and then cleaned it again. The damage had eaten a hole in the grounding shield, but the plastic underneath had kept it from reaching the main board. I also checked over the larger boards and identified the main system board, a power-related board, and a Canon printer control board.
Two dead batteries needed attention. One was the visible lithium backup battery, and the other was a yellow nickel-cadmium pack connected near the printer board. I rebuilt that pack using 1/3 AAA nickel-metal hydride cells and nickel strips, soldering them carefully with high heat and short contact time, and I replaced the lithium cell with one that already had tabs attached.
The printer board had a main fuse that tested good, but one smaller surface-mount fuse tested open. I also checked the electrolytic capacitors, including the surface-mount parts, with an ESR meter. A through-hole 47 µF capacitor turned out to be leaking when I removed it, and the ESR reading confirmed it was out of spec, so I went ahead and replaced all of the electrolytics on the power supply board and cleaned off the leaked electrolyte.
With the machine still apart, I tested the two four-pin stepper motors. Both windings on each motor measured about 30 ohms, and I also verified that they generated enough voltage to light an LED when turned by hand. The broken case corner got glued back together with super glue and reinforced with two-part epoxy, which held well enough for reassembly.
By the time everything went back together, I had a few mystery parts left over, including a washer, a small spring, and a switch piece I couldn’t place. The computer still powered up, the screen still needed time to warm up, and Windows came up once it did. The new batteries worked too, because the date and time settings were retained after a restart.
The laptop side worked, but the printer still didn’t. Turning the printer on caused the same current spike as before, and the carriage never moved.
— Aaron
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Timestamps
00:00 – Intro
01:45 – New Power Supply Adaptors
03:47 – Disassembly
05:05 – First Look
07:37 – New Batteries
12:25 – Boards and Fuses
16:10 – Bad Capacitors
21:01 – PENNY CAM
21:30 – Testing Stepper Motors
24:54 – Broken Plastic
27:03 – Analysis and Reassembly
30:00 – Testing
34:00 – Wrap Up