The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Repairs

If it used to work, it can work again

HP 7475A Plotter: Ceramic-Tip Pen Refill

The ceramic-tip green pen I’ve been using finally ran dry and, having nothing to lose, I tried refilling it.

Grabbing the metal ferrule in the drill press chuck provided enough traction to twist / pull it off, revealing the pen nib assembly inside:

HP 7475A Ceramic-tip pen – ferrule

A pin vise provided enough traction to remove the nib, which had the expected fiber cylinder extending into the ink reservoir:

HP 7475A Ceramic-tip pen – disassembly

I injected 0.5 ml of yellow ink from my lifetime supply of bulk inkjet ink (*), then tried to inject 0.5 ml of cyan, which promptly overflowed. In retrospect, allowing a few minutes for the new ink to seep into whatever’s inside the reservoir would be prudent.

After wiping the mess off the pen and reassembling it in reverse order, it works just like new:

HP 7475A Ceramic-tip pen – C-Y refill

During the course of the first plot, the trace went from green to deep blue-green to a different green, which suggests the yellow ink took a while to make its presence known. No problem; whatever comes out of that tip is all good with me.

The stain around the rim of the pen body above the flange suggests a cap that might come off with sufficient persuasion. If it’s firmly fused to the flange, which would make perfect sense, injecting ink through a small hole drilled in the end might produce better results than ripping the nib out yet again.

(*) This leftover came from the never-sufficiently-to-be-damned HP2000C inkjet printer. ‘Nuff said.

2015-08-06
Verifying Yet Another Sony 64 GB MicroSD Card
The replacement for the second failed Sony SR-64UY MicroSD card arrived:

Sony SR-64UX 64 GB MicroSDXC card

The previous cards were made in Korea, but this one came from Taiwan with a different serial number format:

Sony SR-64UX 64 GB MicroSDXC card – back

The tiny letters on the front identify it as an SR-64UX, but I haven’t been able to find any definitive Sony source describing the various cards; their catalog page listing cards for digital still cameras may be as good as it gets. This one seems to have a higher read speed, for whatever little good that may do.

It stored and regurgitated the usual deluge of video files with no problem, which is only to be expected. This time around, I checked the MD5 sums, rather than unleashing diff on the huge files:
```
cd /media/ed/9C33-6BBD/
for f in * ; do find /mnt/video/ -name $f | xargs md5sum $f ; done
11e31c9ba3befbef6dd3630bb68064d6 MAH00539.MP4
11e31c9ba3befbef6dd3630bb68064d6 /mnt/video/2015-07-05/MAH00539.MP4
... snippage ...
```
It now sits in the fancy plastic display case that the HDR-AS30V camera came in until the previous replacement card fails.
2015-08-02
Monthly Science: Basement Humidity Step Changes

Can you tell when our dehumidifier failed?

Basement Temp Humidity – 2015-05 to 2015-07

The step change in Week 22 shows when the replacement took over. After some poking around, Amazon Prime FTW.

The square-ish pulse starting in Week 26 marks a change from 55% RH to 60%RH and back again, to see how the front panel meter compares with the low end lab-grade hygrometer in the other side of the basement near the Hobo datalogger on the water inlet; they’re all off by a bit, but well within their expected tolerances. The 5% RH height of the step suggests a good match between their incremental calibrations.

It seems dehumidifiers last a few years, no matter which Brand Name you’ve decided to trust, so there’s not much point in developing a deep emotional attachment.

For the record, the old dehumidifier sported a GE label:

GE Dehumidifier label

The new one says Frigidaire on the front, but the label says Electrolux:

Fridgidaire – Electrolux Dehumidifier label

As it turns out, Electrolux bought Frigidaire a while ago, then absorbed GE’s appliances in 2014, so they’re all one big happy family now.

The various names notwithstanding, a recall notice suggests Gree Electric actually makes all the dehumidifiers badged with Brand Names you might think represent something significant.

2015-08-01
Folding Saw Rework

Mary found a folding saw buried under a compost heap at Vassar Farms, where it had evidently been for quite a while. It cleaned up surprisingly well:

Folding saw – pivot shim

I made a crude brass shim to stabilize the crude blade in its crudely bent metal frame; the ugly hole came from freehand punching with the rebuilt leather punch tool. Probably spent as much time doing that as they did on the whole rest of the saw: it’s not a high-quality tool.

It could be an older version of the Harbor Freight Folding Saw, minus a fancy plastic-encased joint screw. I added a dot of Loctite to discourage this one from leaping to its doom.

As with the other pruning saws in my collection, that blade scares me just looking at it. I managed to avoid slicing myself open, although I did stab a finger with a sharp brass sliver…

2015-07-31
Silhouette Glasses: Temple Re-repair

This was not the failure mode I expected:

Silhouette temple – failed repair

As failures go, that one’s survivable; slightly larger epoxy dots should do the trick:

Silhouette temple – re-repair

The other temple worked loose inside the brass tube and rotated freely, so I yanked it out, bashed the tip slightly flatter, and epoxied it back in place, along with overcoating the epoxy dots on the lens to forestall another failure.

This has obviously blown right by the point of absurdity, but …

2015-07-27
Sony 64 GB MicroSDXC Card: Speed Failure Redux

After about 1 TB of data spread over three months and maybe 100 bike rides, the second Sony SR-64UY 64 GB MicroSDXC card I bought last summer has failed… barely two weeks inside the one year warranty.

As with the first card, this one works fine except for the speed: it cannot record at 1920x1080p @ 60 fps. The only indication comes from aiming another camera at the display to capture the failure as it happens.

Just before the failure:

HDR-AS30V – MicroSDXC failure – 1

It’s taking stock of the situation:

HDR-AS30V – MicroSDXC failure – 2

Presumably, it’s patching up the abruptly terminated file:

HDR-AS30V – MicroSDXC failure – 3

Another box is on its way to Sony Media Services…

Over the last year, the price of an almost certainly genuine Sony SR-64UY Class 10 UHS-1 MicroSDXC card has dropped by 2.2 dB: $40 to $24. Now, however, the SR-64UY is the “old model”, so you can pay $30 (-1.3 dB) for an SR-64UY2 rated at 70 MB/s transfer speed (up from 40 MB/s), albeit with no change in the card’s speed class.

Huh.

Both cards failed after writing 1 TB of data (give or take maybe 20%) in 4 GB chunks over the course of 100 recording sessions. The cards still work, in the sense that they can store and accurately retrieve data, just not at the Class 4 (not Class 10) speed rating required by the HDR-AS30V at 1920x1080p @ 60 fps.

The table in the Wikipedia Secure Digital article says Class 4 = 4 MB/s, which is slightly faster than the camera produces 4 GB files in 22:43 min:sec = 3 MB/s. A Class 10 card should write at a sustained 10 MB/s, so the SR-64UY write speed has dropped by at least a factor of 3 from the spec. I’d expect the root problem to be the error correction / block remapping / spare pool handling time has grown as the number of failed blocks eats into the card’s overcapacity, but I have no inside information.

When the replacements slow down, I’ll see how they work as Raspberry Pi memory…

2015-07-10
Presentation Video: Bring Enough Adapters

I plugged my trusty Dell Latitude E6410 into the VGA cable connected to a Viewsonic projector at TechShop Detroit to give the OpenSCAD Modeling presentation, but the display showed a surprising amount of ghosting; whether that was due to a bad cable or the usual presentation gremlins, I cannot say. Fortunately, although I didn’t have a VGA cable, I did have a fair assortment of adapters for the laptop’s DisplayPort output…

On the laptop end, DisplayPort to a DVI-D cable:

Latitude vs Viewsonic – DisplayPort to DVI-D

On the Viewsonic end, DVI-D to HDMI:

Latitude vs Viewsonic – DVI-D to HDMI

Worked like a champ!

The projector in the room for the Arduino Survival Guide presentation had a VGA cable, but had been losing sync and turning itself off, so I unplugged that, rebuilt the DisplayPort adapter string, and continued the mission.

I must add a known-good VGA cable and corresponding adapters to the assortment…

2015-06-29