Worn Chain

worn chain

Old SRAM PC-870 chain (top); new SRAM PC-870 chain (bottom).

The chain on my De Rosa started skipping on the lower gears on the Campagnolo 8 speed cassette. Unfortunately, by the time the chain was skipping, the lower cogs on the cassette were worn out.

Measuring from the center of one rivet to the rivet 23 away on a new chain is 12 inches (~30.48 cm). My chain was over 1/4 inch longer. Park Tool recommends replacing the chain when it is 1/16 inch too long.

Replacing the 8 speed cassette is a problem because of the dearth of parts, considering I need a ≥28 tooth lowest cog. I’ve found Miche 13-28 Campagnolo compatible cassettes on eBay in the UK and Italy, but then I start to wonder whether I should keep trying to support shifting components that were last produced in 1997.

I’ve also found on Branford Bike that a Campagnolo 9 speed hub could be used by dropping one sprocket and using a Wheels Manufacturing 8 speed spacer kit, but that spacer kit is also no longer available.

I Dropped My Macbook Pro

isaligned display, MacBook Pro (Retina, 15-inch, Mid 2012)

I dropped my MacBook Pro (Retina, 15-inch, Mid 2012) on it’s corner. It didn’t cause any internal damage – the computer worked normally – but the the lid (with the display) became misaligned.

Display scraping, MacBook Pro (Retina, 15-inch, Mid 2012)

The misalignment made the lower right corner of the display scrape against the base of the computer whenever the display was opened. I thought if I could loosen the screws that held the display, I could realign the display with the base of the computer.

Loosen 6mm T6 Torx screws , MacBook Pro (Retina, 15-inch, Mid 2012)

I used iFixit’s MacBook Pro 15″ Unibody Mid 2012 Display Replacement (by Andrew Optimus Goldberg (and 5 other contributors) as a guide to remove the lower case and to get to the six 6mm T6 Torx screws holding the display (there are three in each corner).

The repair is fairly straightforward. The only tools that I needed were a Phillips 00 Screwdriver and a T6 Torx Screwdriver.

1. Remove the lower case. (10 Phillips screws)

2. – Note: the links to the following two iFixit links are to illustrate the location of the screws – the screws shouldn’t be removed.

Slightly loosen (do not remove !) all six (three on the left corner and three on the right corner) 6mm T6 Torx screws holding the display to the upper case.

3. Close the lid and move the display so it properly aligned with the computer base (the part that has the keyboard).

4. Tighten the six 6mm T6 Torx screws

5. Reattach the lower case.