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Delete last Admin user from OS X [10.6-10.12]

In “Delete All Users from Mac OS X [10.5]”, we outlined how to boot into Single User Mode and use Terminal commands to delete the last admin user from a Mac running OS X 10.5. The OpenDirectory system has seen some changes since then and the commands have changed too.

OpenDirectory has gone through some hack job of an update by Apple, and still retains error-check messages that you can safely ignore according to Apple’s own documentation (HT4749):

When running dscl(1) from Single User mode, you’ll see this message:

launchctl: Couldn't stat("/System/Library/LaunchDaemons/com.apple.DirectoryServicesLocal.plist"): No such file or directory nothing found to load

This message can be safely ignored.

So the procedure is as follows:

Start your computer into Single User mode by holding Command-S during startup.

Check the startup disk

fsck -fy

Mount the root file system

mount -uw /

Launch DirectoryServices

launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist

Delete the last admin

dscl . delete /Users/username

If you’d like to resuscitate the Setup Assistant

rm -rf /var/db/.AppleSetupDone

Posted in Apple, English.

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By Celia – August 17, 2018

How do I know if I have a BOOST rear hub?

So you want to get some new cranks on your bike but you’re unsure if you need BOOST compatible spacing on your cranks. Getting the correct crank spacing is especially important now-a-days with two piece systems that you have almost no way to adjust the chain ring distance in or out. The front chain ring must align with the median chain position of the rear cog-set to keep the chain-line within optimal angle so not to affect the Q-factor… it just makes for a better ride if the chain-line matches up.

The first clue that you have a BOOST compatible bike and rear hub is if your bike has some kind of marking or sticker saying it is “148 BOOST” – usually on the chain stay. The second clue would be if it came with a 148mm x 12mm thru-axle. To make sure, follow the flowchart below to find out.

 

BOOST FLOWCHART

 

O.L.D. = Over Lock-nut Distance

FTF = Flange To Flange

DONT just assume you have a boost compatible bike and hub because you have a 148 x 12 thru-axle, the axle insertion depth into the frame may be fudged to fit a narrower hub into the frame.

There are EXCEPTIONS. You will encounter bikes with GNOT-BOOST from Surly or future-proofed thread attachments from Raleigh. These bikes have a non-standard 145mm frame width in the rear and accommodates a ±3mm margin by simply having some flex in the frame.

Raleigh even provides a thru-axel that is technically too long for the old 142mm standard and can actually support a 148mm hub (although it’s labeled 142 O.L.D. x 12mm). A thread attachment that is independent from the frame sits on the outside of the frame loosely to compensate for the change in torque angle when the frame flexes.

 

Posted in English, Sidetracked.

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By Celia – June 19, 2018

SRAM NX Eagle vs SunRace MZ90 12 Speed Cassette

Now that SRAM has announced its NX Eagle 12 speed cassette, you can go ALL SRAM on your old bike without searching for a XD driver for your hub. Previously, the only route to do this was to use a SunRace 12 speed cassette, but now SRAM is sramming (sic) the door on the Taiwanese manufacturer.

A quick note for those looking to retrofit a 12 speed cassette onto their 8/9/10 Shimano freehub body/driver. Other than the 29 grams in weight, the difference between the SRAM NX Eagle and the SunRace MZ90 is in the 6th & 7th gear – there is  a slight difference in the teeth count.

SRAM NX Eagle PG1230 (Easier/Slower mid-range) 615g

 11-13-15-17-19-22-25-28-32-36-42-50

That’s

2>2>2>2>3>3>3>4>4>6>8

SunRace CSMZ90 (Harder/Faster mid-range) 586g

 11-13-15-17-19-21-24-28-32-36-42-50

 

That’s

2>2>2>2>2>3>4>4>4>6>8

Maybe the SRAM is smoother than the SunRace? Maybe the SunRace is closer to the XD hub ratio? Until somebody puts both cassettes on exact same bikes and rides them for a 100 miles side by side, we wouldn’t know the difference in performance.

But the BIGGEST DIFFERENCE is that the SunRace CSMZ90 is AVAILABLE NOW and the SRAM NX Eagle PG-1230 won’t be in anybody’s inventory until September – That’s the end of the season for a lot of us in the midwest. Coincidentally, the new Shimano M9100 will not get to local dealers until September either.

 

Posted in English, Sidetracked.

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By Celia – June 14, 2018

Lutron Maestro Dimmer 3-way Crossed Wires

If you are having trouble with the Lutron Maestro dimmer in a 3-way application, check that the two load wires (one on Brass and the other on Blue) are not crossed over.

The LED on the master unit will not light but the load wire will be energized when the FASS is pushed in. That means the Hot wire is connected correctly to the Black screw on the master switch but the electricity is not flowing to the Load on the Black screw on the companion switch, thus there is no path to Neutral.

The LED on the master unit will not light without a path from Hot to Neutral when you cross Brass to Blue/Blue to Brass. With a voltage tester, you’ll quickly find that the wire on the Blue screw on the companion unit is energized.

Posted in English, Home Improvement.

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By James – May 21, 2018

Adding an ACC Powered Equipment to a 2008 Porsche Cayenne Turbo

So, for a while, I’ve been testing out some Dashboard Cameras and iPhone chargers that utilize the Cigarette Lighter Socket in the car. When I decided to mount the equipment to the car permanently, I wanted to draw power from the car from somewhere other than the Cigarette Lighter Socket where I had to keep the ash tray open. I also wanted the power to turn on and shut off with the ignition of the vehicle.

On the Cayenne’s two fuse box by the driver’s side and passenger side doors, there are some open sockets for factory installed options. In the vehicle manual, it should be marked “auxiliary” or “un-used”. But if you peek into the sockets, you’ll see that one side of the fuse socket will have a metal conductor. Using a voltmeter, check that you get 12V when you turn on the ignition and goes to zero when you shut off the car. If you still have something like 0.3V when you shut off the ignition, that fuse is on a timed relay from the CAN-BUS system and not a TRUE switched 12V socket. Don’t trust my photos. Each vehicle is wired differently due to the factory options available on the Cayenne. Always check and re-check with a voltmeter.

There are two of these switched 12V fuse sockets in both fuse boxes for a total of four (4). You may use a fuse tap, a blade socket, or add-a-fuse type piggy-back to get the 12V+ from these socket. On the driver’s side fuse box, there is a hex head screw on the metal frame of the dash to supply the Ground (GND) but this is absent on the passenger side… unless you’re vehicle has been pre-configured with a grounding post for optional equipment. For those who are not so lucky, you can easily tap a hole into the metal frame to screw in a grounding post.

 

Posted in Cars, English.

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By James – December 4, 2017