Tag: Repairs

If it used to work, it can work again

Imagemagick 6 vs. PDF
Come to find out Xubuntu 18.04 ratcheted the ImageMagick security settings up to a dangerous chattering whine:
```
convert p???.jpg "Machining D-bit Drills.pdf"
convert-im6.q16: not authorized `Machining D-bit Drills.pdf' @ error/constitute.c/WriteImage/1037.
```
Fortunately, someone who understands this stuff encountered the problem before I did and posted a great description of the solution.

To forestall link rot, the process looks like:
```
cd /etc/ImageMagick-6/
sudo cp policy.xml policy.xml.base
sudo nano policy.xml
… change one line …
 policy domain="coder" rights="read|write" pattern="PDF"
```
It is completely unclear to me whether ImageMagick (as of ImageMagick 6.9.7-4 Q16 x86_64 20170114 ) requires or merely tolerates the vertical bar in place of commas, nor whether it’s in my best interest to replace "coder" with "*".

In any event, I can once again stuff bitmap images into PDF files.
2018-12-03
Makergear M2 V4 Nozzle: More Silicone!

A Makergear forum discussion on PETG hair and the prevention thereof prompted me to take a look at the silicone coating I’d applied to the nozzle:

M2 – nozzle silicone – applied

That was ten months ago. This is now:

M2 Nozzle – worn silicone coat

The camera sees the nozzle in a mirror laid flat on the platform, making the image less crisp than a direct view.

So the silicone seems a bit worn around the tip, has acquired a few firmly adhered globs, and definitely isn’t as shiny.

Rather than (try to) peel it off and reapply a new coating, I picked off the globs, cleaned around the nozzle, and slobbered a thin layer atop the existing silicone:

M2 Nozzle – more silicone

Extruding a few millimeters of filament pushed the film off the nozzle opening and it now works as well as it ever did.

2018-11-28
Electrolux Vacuum Cleaner: Cord Protection

The ancient (Came With The House™) Electrolux canister vacuum cleaner long ago lost the plastic bushing around the opening passing its retractable cord, which I’d long sworn to replace. A recent trip around the Basement Laboratory paused near the recently relocated Box o’ Wire Loom & Braid, whereupon I snipped off a few inches of split loom and tucked it in place:

Electrolux Vacuum – cushioned cord cutout

Looks and works better than before, anyhow.

The blue flap dangling off the back should latch over the exhaust port, but failed long ago when the latch tab eroded. I attempted a repair, which never worked quite right, and won’t get around to attempting another for quite a while.

2018-11-27
Michelin ProTek Max Tube: Autopsy

The Michelin ProTek Max tube I installed two years ago developed a slow leak this year, which I eventually ascribed to the valve stem, because the sealant should plug any other leak.

Cutting it open reveals the perfectly good greenish-yellow sealant:

Michelin ProTek tube – sealant

The sealant also carries black rubbery grit / shavings / dust, perhaps intended to jam inside larger gashes while the sealant coagulates and binds it together.

There’s a lot of rubber floating around in there:

Michelin ProTek tube – rubber fragments

Dismantling the Presta valve stem show the rubbery crud on and around the valve seal and seat:

Michelin ProTek tube – fouled valve seal

Whenever I pumped up the tires, I finger-tightened the nut to ensure a good seal, as you do with all Presta valves. Obviously, finger-tight can’t handle that much crud between the sealing surfaces.

I’m sorry to say I was right about the leaky valve stem, because I think all the ProTek tubes will fail in exactly the same way.

The valve has small wrench flats making it easy to remove, so I can at least attempt to de-gunk them when they develop slow leaks.

Color me unimpressed.

2018-11-24

Xubuntu Startup Delay vs. xsetwacom

Over the years, various xsetwacom incantations have confined the tablet stylus to the left-hand landscape monitor on my desk. Updating to Xubuntu 18.04 once again changed the monitors names (from HEAD-0 back to DP-1), but xsetwacom stopped working.

My startup.sh script runs from Xubuntu’s “Application Autostart” list, so X is already running and xsetwacom should do the right thing. Alas, even with $XAUTHORITY and $DISPLAY set correctly (automagically by X), xsetwacom still didn’t corral the cursor.

Some rummaging around the Intertubes suggested a delay would allow X to get up to speed and, indeed, sleeping for two seconds solved the problem:

logger "startup.sh - copying Xauthority values"
whoami > /tmp/who
cp /home/ed/.Xauthority /tmp/Xauthority.txt
echo $XAUTHORITY > /tmp/XAUTHORITY.txt
cp $XAUTHORITY /tmp/xauth.cp
echo $DISPLAY > /tmp/DISPLAY.txt
# xsetwacom needs an additional delay after $XAUTHORITY and $DISPLAY become correct
logger "startup.sh - waiting aimlessly"
sleep 2s
logger "startup.sh - doing wacom setup"
xsetwacom --verbose set "Wacom Graphire3 6x8 Pen stylus" MapToOutput "DP-1"
xsetwacom --verbose set "Wacom Graphire3 6x8 Pen eraser" MapToOutput "DP-1"

Sheesh & similar remarks.

The complete Bash script as a GitHub Gist:

	logger "startup.sh – starting"
	logger "startup.sh – setting configurations"
	#setxkbmap -option terminate:ctrl_alt_bksp
	#pactl set-default-sink alsa_output.pci-0000_00_1b.0.hdmi-stereo
	amixer -D pulse sset Master 41%
	amixer -D pulse sset Master 1%-
	gsettings set org.gnome.Evince page-cache-size 500
	# enable Kinesis volume and calculator keys
	#/home/ed/bin/Kinesis/kfreestyle2d /dev/hidraw6 &
	logger "startup.sh – starting applications"
	/usr/bin/thunar &
	/usr/bin/gimp &
	/usr/bin/chromium-browser &
	/usr/bin/digikam &
	/usr/bin/firefox &
	/usr/bin/thunderbird &
	/usr/bin/xfce4-terminal &
	logger "startup.sh – copying Xauthority values"
	# similar lines in .xprofile happen before X grabs the display
	whoami > /tmp/who
	cp /home/ed/.Xauthority /tmp/Xauthority.txt
	echo $XAUTHORITY > /tmp/XAUTHORITY.txt
	cp $XAUTHORITY /tmp/xauth.cp
	echo $DISPLAY > /tmp/DISPLAY.txt
	# xsetwacom needs an additional delay after $XAUTHORITY and $DISPLAY become correct
	logger "startup.sh – waiting aimlessly"
	sleep 2s
	logger "startup.sh – doing wacom setup"
	xsetwacom –verbose set "Wacom Graphire3 6×8 Pen stylus" MapToOutput "DP-1"
	#xsetwacom –verbose set "Wacom Graphire3 6×8 Pen stylus" MapToOutput "HEAD-0"
	xsetwacom –verbose set "Wacom Graphire3 6×8 Pen eraser" MapToOutput "DP-1"
	#xsetwacom –verbose set "Wacom Graphire3 6×8 Pen eraser" MapToOutput "HEAD-0"
	logger "startup.sh — done"

view raw startup.sh hosted with ❤ by GitHub

The cruft in there reminds me of previous fixes / workarounds / haxx, so it’s not entirely wasted space.

2018-11-20

Lenovo Headset Volume Control Lube

The volume control ~~wart~~ pod on the cable of my old and longsuffering Lenovo headset had been dropping out the right channel for a while, eventually prompting me to discover it comes apart by simply pulling on the halves:

Lenovo Headset – control pod

There being no way to get closer to the open-frame volume pot’s innards, I eased a drop of DeoxIT Red along its edge (upper in the photo), slipped another drop into what’s presumably the wiper opening in the knob, and ran it through enough cycles to spread the juice evenly.

Reassemble in reverse order and It Just Works™ again.

2018-11-18
HP 6201B Power Supply Meter Switch Rehabilitation

The meter range switch on Squidwrench’s HP 6201B bench power supply became erratic enough to get me to tear it apart:

HP 6201B Power Supply – meter switch nut

For future reference, apply a 9/16 inch deep socket after loosening two teeny setscrews in the knob.

The date codes suggest a mid-70s assembly, but the design dates back to the 60s with no plug-in anything:

HP 6201B Power Supply – meter switch in panel

Rather than unsolder eight switch leads, I wrangled it into a visible location:

HP 6201B Power Supply – meter switch rear

The knob and shaft sit on a separate metal bracket held in the white plastic ring with a pair of expanded prongs. Squashing the prongs together released the bracket, so I could see both sides of the switch wafer:

HP 6201B Power Supply – meter switch front

Note the copious markings which would, in the event of an actual finger fumble, give me a better chance of reassembling the spilled guts. Turned out not to be necessary, but it’s good to be prepared!

The actual repair consisted of easing a drop of DeoxIT Red into each side, spinning the central switch wafer / contacts a few dozen times, then reassembling in reverse order. Re-bending the prongs turned out to be the most difficult part, eventually requiring the designated Prydriver, and ended well enough.

A quick test with a 100 Ω power resistor shows the supply was working fine and the switch produced the expected results without glitches or twitches:

HP 6201B Power Supply – test load

You just can’t beat the performance of old lab equipment!

2018-11-14