666.66 ohms, got it

Quietly, secretly cursed meter

Okay, let’s try that again

Meter that is, I swear, not cursed. No really. Not cursed at all. Might be cursed at some other point in time, but not now.

I could try to explain what was going on with the curse, but I’ll leave it at this: it just… completely afflicted the resistance measurements and made me think a whole roll of SMT resistors were somehow open circuit right off the reel. Then another equally cursed resistor in the office suggested the same thing. Yeah, the only explanation for this level of synchronized brokenness is an ancient horrible curse.

I need a sign for the workshop door that says “It has been [slot to hang up a number tile] days since last unspeakable horrors beyond human comprehension”. I will not elaborate here as to why, but it’s now a matter of public record if you know where to look. FNORD!

Videonics video mixer/switcher power supply

Videonics video editing switchers are pretty common but their power supplies are also commonly lost. The connector is a standard 6 pin DIN type and here is the pinout:

Pins 1 and 4: +5vdc (probably regulated) 4.5 amps

Pins 2 and 5: ground

Pin 3: +10vdc 0.4 amp

Pin 6: -10vdc 0.4 amp

I haven’t looked inside the switcher to see if it needs the +/-10v to be regulated voltages. My guess is the +5 needs to be. If I had to homebrew a power solution for one of these I’d probably start with a PC power supply and run the +/- 12 rails through buck converters or LM7810 + LM7910 regulators (my guess is that the load on these channels is pretty minimal).

Very proud of those knobs, are we?

I got an Alta Cygnus video frame sync/processing amp a while back that didn’t work because the cap from its fuse holder was missing. No big deal, just gotta open it up and change the holder.

Well, somehow this completely escaped me ever photographing the process or what’s inside the unit, but it’s got one hilarious “feature” I have to wonder about.

Simple. Elegant. MADNESS.

So, the chassis of the unit has the motherboard (enormous square monster utterly tessellated in DIP ICs) screwed to the bottom panel. The top cover slides forwards to remove it and it’s one piece, including that very 1980s chamfer.

Do you…. do you already see what that means? If you were expecting it to be cursed, yes, you do…

See all those knobs? Every one of them is a very nice little molded plastic knob with a metal insert that holds it to the control shaft with a small hex screw.

Every one of them has to come off to slide off the cover.

Yeah. Sure. That was a great idea.

It’s the top of the line of utility sports, unexplained fires are a matter for the courts

I mean, once I got past that and replaced the fuse holder it looks like it’s gonna work perfectly fine. But seriously, what on earth?!

These brochure pages are all the documentation I can find on the unit, I’d love to score a manual though as there are a lot of internal adjustments and dip switches I’m curious about. But am I curious enough to have to remove and reinstall all those knobs?!

Tech note: Canon printer error B200, B201, B202, B203, B204, B205, B206, B207, easy fix?

It’s no secret that Canon inkjet printers have a couple of cry wolf failure modes that claim to be the end of life for the printer, but are repairable with no parts or special tools. The most common one is the ink disposal error where a software counter expires the silly thing, but it’s resettable… Although Canon would like you to think it isn’t.

Anyway, our trusty Canon MX490 shut down yelling “needs service, B202”. Canon’s official support document says this means it’s dead or at least that you have to replace the cartridges because they “overheated”.

I have been working on inkjet printers since the late 90s and have literally never heard of this failure mode. Furthermore, I’ve never seen a printhead actually do anything close to burning out– at worst sometimes one has had a really stubborn clog, and leaving it lying on a paper towel soaked with distilled water revived it. (Isopropyl alcohol works too but I swear water does it better!)

Radio Shack even used to sell a kit for cleaning the printhead that had a little strip of microfiber brush material and a pen filled with distilled water to wet it with then stroke the head across it. It worked fine but after I figured out a paper towel worked better on certain cartridges I just went low tech.

Anyway, the other part that needs to be clean for correct operation of an inkjet cartridge or printhead module is the electrical connector between the head and the rest of the printer. There’s a matrix of little yellow metal dots or squares on the cartridge, usually on the side that faces the back of the printer. Grab a cotton swab and isopropyl alcohol and clean this, then GENTLY dab clean the matching contacts on the printer carriage, being careful not to snag and bend any parts.

This fixed the printer! No cartridge replacement was needed, I powered it up, it returned the carriage home, did a quick cleaning cycle, and returned happily to service like nothing had ever happened.

Anyway, usually you can access these areas by just sliding the cartridge gently into reach with the printer powered off. Please be warned you may touch ink goopus while doing this. If it’s not possible to move the carriage into reach, you may need to start the printer doing something and yank the power while the head is out of its home position. I don’t know if any Canon machines are like this, but on the old HP Deskjet 600-700 series the cap assembly that seals around the printhead when not in use was raised up by a motor and firmly locked the carriage in the home position. (Sounds like a nice measure to prevent shipping damage!)

On most printers including this MX490, just sliding the cartridge towards the middle uncaps it. If you’re in there, you can also clean the caps and squeegee blades that are near them, this may cure lingering print quality issues like banding or stray ink drops/blobs.

I mentioned specifically cleaning the cartridge contacts with isopropyl alcohol because Hewlett-Packard once had a service note out recommending it – they had a lot of some sort of lubricant (dielectric grease?) that was being factory applied to new cartridges that turned out to be a little too good at maintaining a film between the metal surfaces, causing the cartridges to print poorly or not at all. Their fix was to clean it off. On my printer, it removed visible ink deposits just as well.

If you happen to be here because you’re trying to clean the printhead, please be sure to wipe the squeegee and cap and, if present, clean the two concave grooves adjacent to the printhead with a wet swab. Otherwise you’ll wind up with the head getting re-gooped immediately upon putting it back in, and you don’t want that.

Yes, I need to revise this with pictures, but for now, here’s an unrelated image:

I mean, maybe if you had a lot of droolage from the cyan, magenta, and yellow printhead, it’d look just like this tri-color foaming wax

Flipper, where are you?

I confused the tiny dolphin somehow. My Flipper Zero either ran out of battery power, or maybe actually didn’t, and seemed to refuse to fully boot up or charge. The charge status claimed both charged and empty, and “Limited to 3.8 volts”. Strange. I thought I’d have to go in there and disconnect the battery to reset it but it was easier than that!

I found the reset instructions and they’re kinda amusing:

1) Plug in the USB charger, go to Settings / Power / Power Off

2) confirm with the sad looking dolphin that you want to power off. A very Windows 95-esque “It’s now safe to unplug” screen comes up.

3) reconnect the USB charger

4) Hold the back button (20-30 sec?)

Bam, it lit right back up and resumed normal operation. The battery seems perfectly fine.

I’m not really sure what confused the device in the first place, but it just required a silly little dance to get it back.

You know what, just yeet these with extreme prejudice

This WAS a rubber stick on cushion. These are often found as feet on electronic equipment. I actually don’t know why it was ever in there.

It didn’t stop there and ran all the way down the chassis. The first sign of trouble was that I went to pull the scope out of its housing and it just stayed stuck, but then came out with a big SCHLORP sound.

I’ve begun ripping these rubber cushions off my older electronic gear and replacing them with sticky back felt feet if necessary. I wonder if there are silicone rubber equivalents? The silicone rubber keypad on this oscilloscope still works fine despite being made in the early 1990s but that superfluous cushion had to go before. I’m glad I got it before it oozed right out the holes in the back.

As nasty as this would be I’d rather soak in that substance than the contents of the Tesla Dumpster Pool

Primeview remote codes

I just got a Flipper Zero and it allows for saving and replaying the magic from infrared remotes. I had a preservation target in mind, just in case –
Primeview monitors… they’re fancy, expensive, have great color rendition and can match your on-set lighting for film and TV very well, and they use an akwardly hard to obtain remote that’s, well, uh, hard to come by and awkward. I dunno. It has a lot of buttons that probably never get used by the Primeview monitor and it looks like it was originally intended to be the generic remote for some other kind of TV with a digital broadcast and radio tuner (!). Anyway, here’s all the buttons, use whichever ones you need. 🙂


I don’t really know what that file format is but it looks fairly straightforward and may be usable for LIRC and other configurable infrared remote control systems.

As I started to get down into the buttons at the bottom of the remote, I noticed the RGB LED light strips on my workbench starting to cycle between colors. Aha, wehave a bizarre match! I remember that the Favorite channel button was one of them.

name: Fav
type: parsed
protocol: NEC
address: 03 00 00 00
command: 0C 00 00 00

I guess I need to figure out what I did to those configuration files but my brain is on fire

First, these three pictures of early stage tri-color foaming wax

Yeah— so I did the config all wrong for this server. Virtual host declarations aren’t in the files they should logically be in and things overlap and I just accidentally found some way to get a horribly blank directory listing to load instead of this page! Very weird, I think I just need to make a backup copy and rewrite the stuff. My apologies if you catch things broken as I’m doing it.

Pictures from The Cloud:

This is the top of the tower elevator and the inside of the tower top hut on Transtower. The lower level is really weird and basically was built by and for Gumby.

My brother sends me regular updates on this kitty named Luna being a cutie peets.

A newborn car wash? I think it’s a Mark VII system.
The ham shack as seen in “Akiba’s Trip”
Rainbow jugs
Useful meme

So I made a previous silly post about this Weston 622 milliammeter… It’s pretty interesting. Inside that removable plug, sealed in place with beeswax, are some kind of heating element and one side of a thermocouple. The other side of the thermocouple is in the meter body. This is actually really similar to the platinum RTD RF power measurement technique that’s the gold standard for average power level measurements on signals that have a varying peak to average power ratio (PAPR). It measures the RMS, “heating value” of the input by….. measuring its heating value! I tested it with DC because that was convenient and the 60+ year old meter agreed with a modern Fluke DMM.

I haven’t come across a ton of info or any original manuals on this meter, but it’s a little different than most I’ve seen when just searching the web or looking at eBay listings (it’s fairly common!). Mine has the thermocouple and heater in an interchangable plug, whereas most have it buried inside the meter case. This suggests that at some point Weston intended it to be used with different detectors. I wonder if there was to be one with 50 ohm coaxial input? A passive thermal RF power meter would be pretty cute!!

UV LED encapsulant musing.

My hair wasn’t glowing. I needed to fix this.

I have this LED blacklight bulb in a desk lamp at my bench at work and it normally makes my hair glow nicely. In case you’re wondering— it’s thanks to the Iroiro Colors 300 series dyes. Neon Yellow, Neon Red, and Neon Pink are probably the brightest. I’m always tempted to just throw Neon Pink over my whole head because it looks so nice, but I am absolutely incapable of deciding on just one color so I continue to be a rainbow.

Anyway, this is what I get when it’s working:

I don’t turn the blacklight off, so it was just kinda cooking there for over a year. Eventually it became a dark purple light that didn’t make any magic.

New bulb
Old bulb

The most noticeable difference is that the encapsulant on the “filament” arrays has darkened right over each emitter.

Old bulb, Well Done
New bulb, the encapsulant is water clear

I had read a while back that some of the nasty but revolutionary UV-A emitters from Nichia, when they first came on the market, were using a metal TO-18 can with a quartz end window to avoid this.

I wonder how many other LED products may still suffer this degradation? I will say I got a good amount of life out of this $12 bulb so I’m not exactly mad, but I feel like if whoever made the “filaments” had used a better goopus on top of the array, it’d still be working fine.

As for the old bulb, I still like its weird violet glow and might try to scrounge up another weird fixture to put it in like this funky 3d printer-activated flicker lamp. I swear I can also see the HVAC chiller out back cycling in its brightness level.

I used to hate this thing but it’s slowly grown on me

MiniDV weirdness

I got a broken MiniDV camera pretty much free for the asking and took a look inside. Well, I’m glad I didn’t go in expecting a successful repair because oh no

Probably 50% of the weight of this thing is tiny screws.

I was intrigued and horrified all at once that a tiny cog belt was visible! See it peeking out there to the left of the rubber pinch roller?

The iris was stuck closed. I’ve seen this failure on a few JVC mini DV cams and had never opened one up to investigate. Upon seeing the mechanism I’m not surprised this happens. It’s a combined aperture and ND filter with two weird thin plastic blades that have stuck together, actuated by a very tiny rotary solenoid.

ND filter in line
Fully open
The lens has two moving elements, one to zoom and one to focus
The sensor

So there’s the tape transport, it has only two motors aside from the head scanner. A very small pancake capstan motor is under the side where the pinch roller is; the one standing in the corner controls the load/unload action.

And finally, that tiny cog belt runs between the capstan motor and a pulley that drives the gear idler. The tension is regulated by a spring loaded brake (felt?) under the take-up reel and that’s pretty much it. This isn’t exactly a very sophisticated transport.

I can’t really imagine actually repairing one of these. Everything had to come out to get to the back of the transport and it’s a total mess in there. Wow.