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How I repaired the broken hinge on Sigmarion II (tons of pics)

hpcboy Page Icon Posted 2020-11-01 2:36 PM
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H/PC Philosopher

Hong Kong SAR
The original post can be found here: https://solochampion.blogspot.com/2020/11/book-of-sigmarion-ii-chapter-1-revival.html

The whole exercise is a follow up on this previous post: A question about the hardware design of Sigmarion 2

Hopefully, by reposting it here, those who have an old HPC with broken component collecting dirt and dust may see a new possibility to revive the precious machine and embrace it once again.

Okay, let get started.

My Sigmarion II came in an excellent condition. Not even a single scratch or spot of dirt. However, like its many brothers, its hinge suffers from a design flaw that the internal part holding the hinge nut is broken, loosening the moving mechanism and disabling the screen to support its own weight.

Therefore, the very first quest for the Solo Champion is to lift this inherited curse once and for all.

To open the machine, it would be easier to start with the the phone connector. Pay attention to where the hooks are. Use a phone opener or a small flat screwdriver to pry there.

Continue to work on each hook around the machine.

See the LCD cable and connector (left), the metal hinge (right).

This looks like the main memory (ROM and RAM) board of the machine.

The LCD cable is a delicate component. So to avoid any possible damages, loosen the LCD cable by pushing (gently) the brown lever.

Look. The metal hinge was detached from where it was supposed to be... This was where the curse lay.

Another damage to the hinge was the shaft holding another screw of the hinge was snapped. Part of the screw shaft was gone too.

The metal hinge was supposed to be locked inside here, but not anymore.

The source of the problem was that thin plastic nut holding the metal hinge in position was totally shattered....

If this was some other part on the casing, gluing the pieces back together would be the solution. But not in this case. The actual cause was that the original design of the plastic nut was so thin and even worse with zero support around it, despite the empty space around the component. The plastic was doomed to break apart sooner or later because there was simply not enough protection against the relatively large pressure on this particular spot resulted from the movement of the metal hinge. A clear oversight of the design. No excuse could be accepted, even for such a renowned manufacturer as NEC.

And simply gluing this second broken piece back wouldn't help much either. Once broken, it will be broken again just more easily.

What I wanted was a permanent and effective solution. I decided to make my own custom replacement part.
Using my limited 3D modeling skills, I created a simple replacement design on TinkerCAD.

Then I transferred the finalized STL file to Cura, the most popular opensource 3D model slicer.

With the help of my trusted Creality Ender 3 Pro (with silent mainboard and firmware upgrade), the new component was beginning to come into physical existence. The printing process would take a bit less than 30 minutes.

In the meantime, I proceeded to remove the remaining bits of the original part, except for the four tiny bumps in a crosshair pattern for a good reason which would be revealed very soon. A purpose designed sculpting knife worked better than a typical Xacto knife here.

Okay, this looked clean enough.

It's about time. My custom made hinge nut was ready.

See the four notches along the rim? They were meant to fit those four bumps and help to keep the nut to stay in position.

It fit perfectly on the metal hinge.

It also fit perfectly in the position of the original nut.

So now it's time for the real show. The Champion cast the Superglue spell to fixate the replacement part.

To amplify the result, the Champion shot a stream of hotglue to fill up the empty space around the nut to ensure that the part won't break or get loosened ever again.

"Take that, you fiend!"

Also apply hotglue around the second damaged site.

Continue to fill up any gaps that may help back up the area that would bear the pressure when turning the hinge.

Both the superglue and the hotglue became hardened after several minutes. It's high time to install the metal hinge back into the screen casing, right inside the hexagonal hole of the custom made nut. The Champion tested the strength of the repaired site and was satisfied with the result.

Fitting the casings back together, the screen hinge of the Sigmarion II can now operate normally once again!

3D printing + DIY + HPC = I was having a triple FUN Sunday!

Edited by hpcboy 2020-11-01 3:04 PM
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Jake Page Icon Posted 2020-11-01 2:53 PM
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H/PC Vanguard

Choking on the stench of ambition in Washington DC
Man, what a nice write-up. Sadly, I don't own a Sig, but that doesn't stop me from appreciating your careful work.

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hpcboy Page Icon Posted 2020-11-01 3:13 PM
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H/PC Philosopher

Hong Kong SAR
Thanks, Jake for your kind comment. I just hope that others who may come across similar (non-electronic) hardware issues in their old devices do not necessarily give up on their buddies.

By the way, the Sigmarion II is a very interesting machine. It's very close to Jornada 720 except that it's using a MIPS processor. Another shortcoming is it lacks a PC card slot like the Jornada. But thanks for stingraze's pointers there are actually easy mods to enable USB support for Sigmarion II either by adding a builtin USB flash memory or by building a regular USB port. I am going to write a comparative review of these two machines.

For now, I am about to recell the battery pack of this rare little beast.

Sigmarion II pops up every now and then on the Yahoo! Japan auction site. The coolest thing is it is usually sold dirt cheap there, saying about 2,000-3,000 JPY.
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