Tag: Repairs

If it used to work, it can work again

Huion H610Pro (V2) Tablet vs. xsetwacom

For unknown reasons, likely having to do with ordinary system updates, both the Huion H610Pro (V2) tablet’s device name and the display output’s name have changed. This came to light when I discovered the tablet’s stylus was no longer constrained to the landscape display, which worked fine when I set it up barely a month ago.

Running the setup command manually:

xsetwacom --verbose set "HUION Huion Tablet Pen stylus" MapToOutput "DP-1"
... Display is '(null)'.
... 'set' requested for 'HUION Huion Tablet Pen stylus'.
 <<< snippage >>>
... Checking device 'HUION Huion Tablet stylus' (11).
... Checking device 'HUION Huion Tablet eraser' (19).
Cannot find device 'HUION Huion Tablet Pen stylus'.

Apparently, the device formerly known as HUION Huion Tablet Pen stylus is now called HUION Huion Tablet stylus.

Fine, I can live with that. Try again:

xsetwacom --verbose set "HUION Huion Tablet stylus" MapToOutput "DP-1"
... Display is '(null)'.
... 'set' requested for 'HUION Huion Tablet stylus'.
 <<< snippage >>>
... Checking device 'HUION Huion Tablet stylus' (11).
... Checking device 'HUION Huion Tablet eraser' (19).
... Device 'HUION Huion Tablet stylus' (11) found.
... Found output 'VGA-1' (disconnnected)
... Found output 'DP-1' (disconnnected)
... Found output 'HDMI-1' (disconnnected)
... Found output 'DP-2' (connected)
... CRTC (2560x0) 1440x2560
... Found output 'HDMI-2' (disconnnected)
... Found output 'DP-1-8' (connected)
... CRTC (0x0) 2560x1440
... Found output 'DP-1-1' (disconnnected)
Unable to find output 'DP-1'. Output may not be connected.

Apparently, the video output formerly known as DP-1 has fissioned into DP-1-1 and DP-1-8, with only the latter connected. Weirdly, nothing happened to DP-2.

Once more, into the bleach:

xsetwacom --verbose set "HUION Huion Tablet stylus" MapToOutput "DP-1-8"
... Display is '(null)'.
... 'set' requested for 'HUION Huion Tablet stylus'.
 <<< snippage >>>
... Checking device 'HUION Huion Tablet stylus' (11).
... Checking device 'HUION Huion Tablet eraser' (19).
... Device 'HUION Huion Tablet stylus' (11) found.
... Found output 'VGA-1' (disconnnected)
... Found output 'DP-1' (disconnnected)
... Found output 'HDMI-1' (disconnnected)
... Found output 'DP-2' (connected)
... CRTC (2560x0) 1440x2560
... Found output 'HDMI-2' (disconnnected)
... Found output 'DP-1-8' (connected)
... CRTC (0x0) 2560x1440
... Setting CRTC DP-1-8
... Remapping to output area 2560x1440 @ 0,0.
... Transformation matrix:
... 	[ 0.640000 0.000000 0.000000 ]
... 	[ 0.000000 0.562500 0.000000 ]
... 	[ 0.000000 0.000000 1.000000 ]

Well, that worked.

Actually, I had to constrain the stylus to DP-2, then jam it back on DP-1-8, to spread the tablet’s horizontal extent over the entire monitor. Updating the startup script started the tablet properly the next morning.

The new device name certainly makes more sense and, perhaps, the X output connection now recognizes the landscape monitor’s ability to pass its DisplayPort video stream along to a second monitor.

2020-01-14

Blackburn Flea Bike Headlight

A Blackburn Flea bike headlight and its USB charger emerged from the packs on our Young Engineer’s Tour Easy, but the battery was completely defunct. With nothing to lose, I applied a small screwdriver to crack the case:

Blackburn Flea – opening case

The battery is a single cylindrical lithium cell:

Blackburn Flea – battery

The USB charger seemed defunct, as it produced only a few dozen millivolts when connected and plugged into its wall wart. Cracking its case revealed a tiny buck power supply with no obvious damage, but also no output.

So I manually charged the cell:

Blackburn Flea – external recharge

Definitely not recommended practice, but a bench supply set to 4.1 V and current-limited to 100 mA gets the job done: the current stays at 100 mA while the voltage rises to 4.1 V, then the current drops to just about zero over the next few hours with cell held at 4.1 V.

Unfortunately, the cell really was defunct, even after a few cycles, so I conjured a not-dead-yet lithium cell from the heap:

Blackburn Flea – measurement setup

Given a good supply, the Flea still works perfectly:

Blackburn Headlight – Kyocera Li-ion – 50 mA-div

The yellow trace shows the battery holding at 4 V while the LED current runs at 150 mA (3 div × 50 mA/div). You wouldn’t want to run ordinary 5 mm LEDs at nearly 40 mA, but Blackburn surely specified good parts.

Replacing the Flea’s internal cell seems impossible, given its peculiar form factor, and grafting the PCB to an external cell makes no sense, given that it’d then need a custom bike mount.

So another chunk of electronics goes in the e-waste box.

Ride on!

2020-01-13
Needle Case Repair

A needle case emerged from the bottom of a drawer in need of repair:

Needle Case – unglued

The original joint used solvent glue and I suppose I could refresh it with acetone, but two blobs of hot melt glue seemed easier and, IMO, more durable.

In any event, it’s once more ready for use:

Needle Case – repaired

Hooray for another zero-dollar repair, although you can see why nobody else does them these days.

2020-01-12
HP 7475A Plotter: Ceramic Pen Tip Wear

An upcoming show-n-tell prompted me to make sure the HP 7475A plotter still worked and verify the pen stash. One of the ceramic pens expired during the first test plot and a refill didn’t improve its disposition, so I pulled a new-old-stock pen from its wrapper.

As expected, the defunct pen’s ink supply core had worn down to the surrounding ceramic nib:

HP 7475A Ceramic-tip pen – worn core

The new pen looks like it has a brush sticking out:

HP 7475A Ceramic-tip pen – fresh core

The new pen’s core looks slightly larger and, in fact, it’s labeled as 0.4 mm rather than 0.3 mm. The new-old-stock pen stash includes a few 0.2 mm ceramic pens; I should think of something requiring hairline detail.

It passed the manual scribble test and promptly ran out of ink during its first plot. I injected some blue ink and it’s now plotting happily for the first time in its life.

2020-01-10
Obsolete DRAM Collection

As you might expect by now, I harvest various bits & pieces from the PCs falling off the trailing edge of my assortment. The bag of obsolete DRAM recently floated to the top of the heap:

DRAM Assortment – overview

Half a gig of ECC RAM from what might have been a fire-breathing Pentium Pro box:

DRAM Assortment – 256 MB ECC

The PCBs along the top apparently filled vacant memory slots.

Some 32 and 64 MB DRAM from a few IBM laptops I turned into picture frames:

DDR2 DRAM in assorted sizes & speeds:

DRAM Assortment – PC2 DDR

PC133 DDR DRAM, with four sticks of 1 GB PC3 along the bottom:

DRAM Assortment – PC133

If you look closely, you may see something you can use. No reasonable offer refused …

2019-12-17
Cheese Slicer: JB Weld Epoxy FTW

The JB Weld epoxy I slathered on our trusty hand-held cheese slicer a year ago continues to withstand daily washing and occasional trips through the dishwasher:

Cheese Slicer JB Weld 1 year – top

The bottom is in fine shape, too:

Cheese Slicer JB Weld 1 year – bottom

Compare it with XTC-3D epoxy, which admittedly isn’t rated for continuous water exposure, after a year:

Cheese Slicer – epoxy coating split

JB Weld FTW!

2019-12-16
Mini-Lathe DRO Battery Life

The Mini-Lathe DROs eat a 390 alkaline coin cell a year, more or less:

Mini-Lathe DRO – battery life

The other DRO’s cell was 10 mV higher, so it might have survived another few weeks. I’ll call it a year, as the OEM cells failed half a year after I got the thing and these are the second set.

The last time I did this, I wedged a thin foam sheet below the display PCB to put a bit more pressure on the (+) contact tab sticking down from the middle of the plate:

Mini-Lathe DRO – battery compartment

The (-) contact is a pad on the PCB below the battery compartment. The glaring metal reflector is part of the curved cell retainer.

I still wish the DROs didn’t collide with the compound slide, but you can get used to anything if you do it long enough.

2019-12-11