Portable Misc - Hinge clip fix, Earlier features, Super Static memory

[David Cook]

Broken Corners

I've seen enough broken cases that I lean toward being pragmatic rather than attempting a pristine repair. A common fracture is on the middle sides where the screen's hinge clips are secured. I usually can recover the broken pieces during disassembly. In this case, a broken-off corner was missing completely. Using its broken twin from the opposite side as a model, I took a scrap piece of ABS and milled it to mimic the dimensions. (My 3D printer is packed away somewhere in the basement).

After cutting a chunk free from the larger scrap, I used a metal file to carve away the profile to match the broken corner. As you can see below, my handwork isn't a perfect match, but it is definitely good enough to be functional. Gorilla epoxy firmly attaches and fills the gaps. I post this to demonstrate that sometimes you can use what you have lying around.

Early M5120 Differences?

I noticed a couple of things while working on a 5120 from December 1989. I'd be interested in hearing from people that have Portables manufactured in September (or earlier).

First, the ROMs have odd labels. (Aside, yes this board needs an ultrasonic bath.)

Second, the cable pulls for the keyboard and trackball are made of a weak stretchy plastic.

Apple upgraded to a tougher material in later production.

Lastly, the molded clip for the power cable is missing.

It should look like this.

Technology Works Super Static

I received a Portable with this 1 MB memory card. However, it doesn't seem to work. There aren't any errors -- it just isn't recognized. The circuitry lacks any sort of PAL/GAL. Any ideas on what's wrong?

- David

 

[JDW]

Gorilla epoxy firmly attaches and fills the gaps.

What specific part number of Gorilla epoxy did you use?
And, have you tested how strong the bond is to polycarbonate?

I used DCM to weld the broken hinge when I did my repair (which is a different part than what you repaired). But the key difference is that my break was clean without gaps, while yours appears to have gaps. DCM melts the pieces together for a very strong bond, but it won’t do gap filling at all. DCM is also rather toxic and not so fun to deal with.

I’m mainly curious about your choice of epoxy for plastics because I’ve been using J-B Weld Plastics Bonder 50133 for my PowerBook 165c and 180c standoff repairs (which I’ve been showing on YouTube), and for that application it has worked OK so far. My big issue is that I can't buy from Amazon Japan all the same epoxy brands that you guys in the USA get access too, although there are various Gorilla brand epoxies on Amazon Japan here:

https://www.amazon.co.jp/s?k=gorilla+epoxy&crid=2KD2VUGE9E948&sprefix=gorilla+epoxy%2Caps%2C170

 

[David Cook]

What specific part number of Gorilla epoxy did you use?

I use this:

Amazon.com

have you tested how strong the bond is to polycarbonate?

It seems genuinely strong. I know the true test is whether the part breaks at the bond site or on a new break at some other location on the original plastic. But, obviously we don't want to perform that test. : )

I wasn't sure that this really was polycarbonate as it doesn't seem tough enough. I had a scrap piece which shows the following characteristics:
1. Melts (not burns) when heated: Yes
2. Sinks (not floats) in water: Yes
3. After being lit on fire, it self-extinguishes (doesn't keep burning on its own): Yes
4. Color of flame: Orange
5. Color of smoke: Black and sooty.

That matches polycarbonate. Do you have a primary source that says it is polycarbonate, or did you deduce it?

- David

 

[JDW]

That matches polycarbonate. Do you have a primary source that says it is polycarbonate, or did you deduce it?

Listen to the official Apple mention at 8:36 here:

And for the doubters, Logical Deduction that even Spock would appreciate also comes into play. The Macintosh Portable housing is absolutely made of Polycarbonate, based on the fact those machines just don't yellow and the housing is surprisingly robust even today. Had that housing been ABS, it would be like the Macintosh Portable's spacebar, which I agree was probably outsourced and used brominated ABS for some strange reason. The other keys don't yellow though.

The transparent plastic I used to reinforce my broken polycarbonate hinge (linked in my previous post) was purchased by me on Amazon Japan, and it is advertised as being polycarbonate. So my DCM fix welded PC to PC, albeit with one type being transparent and the other opaque.

I consulted with AI in an attempt to get you more definitive proof, and AI contends that if you put Acetone on ABS, it will break down rapidly, whereas PC will resist Acetone quite well. I've never used Acetone myself, so I cannot say from personal experience doing that test.