Revisiting the Printrbot Simple Metal

The Printrbot Simple Metal was a really cool design. It’s a Cartesian 3d printer built like a brick house by Printrbot out of Lincoln, California, who went out of business facing powerful competition from a lot of low-cost Chinese printers but recently decided to get going again. One of my coworkers had one that had an old version of Marlin on it (1.0.0?!) and I wanted to update it to improve on some features and add support for a heat bed.

oh she’s a brick—– house

It was available with or without a heated bed, and even if you didn’t have one, it can still be added easily using a stick on heater mat/thermistor like this. The connectors are present on the Printrboard controller for it. One cool thing about the Printrboard: it has two big beefy mosfets onboard, and the DC in connector just mates straight to a standard ATX12V connector on a PC power supply. All you’d need to do to power the Printrbot is go to the ATX motherboard connector on the supply and jumper the small green wire to one of the black grounds to make it auto start. On Rev. D boards, this was a 4 pin; on Rev. F, it’s 6 pin.

There is a solder jumperable pad, supplied OPEN, for USBPWR 5V. This will allow the board to power up from the USB host it’s plugged into. Don’t jumper this unless you have a very good reason to for your configuration. An onboard switching regulator will supply +5V to the components onboard once +12V is input to the ATX12V connector.

This is based on the RevF board, as that just happens to be what landed on my bench. Printers using the RevD are not uncommon too, apparently.

Steppers: The board supplies four Allegro A4982 stepper drivers, an improved version of the A4988. These do not have a heatsink on them like a lot of newer boards do, but I haven’t seen them get hot either. It certainly won’t hurt to add some stick-on sinks if you want. The datasheet suggests that the lion’s share of the chip’s thermal dissipation goes out the bottom though. The driver type in Marlin should be left on A4988 as the I/O behavior is identical.

Microstepping IS supported on this board – you will find a small solderable jumper pad next to each driver. If you solder bridge that entire pad, you will get 1/8 microstepping. On this particular printer, all four are un-jumpered and microstepping is not used. On a printer that was NOT built like a brick house, this would lead to it having a very loud sound about it. On the Simple Metal… it just sounds smooth and sweet. Don’t forget to change your steps per unit if you bridge the microstep pads! The VRef voltage that sets the stepper motor current comes off a DAC, making the motor current adjustable in software. I haven’t experimented with this yet or found any reason to move it off defaults – the motors and drivers stay cool and I am not experiencing any skipped steps, even when making the printer SCREAM at 150mm/sec! (it will DO IT with the stock hotend and not skip any steps, but you will lose detail. Dang.)

Updating Firmware: Before updating, if you’re doing this on an already functional machine, get your EEPROM settings with M503 and copy them into a text file. Otherwise you’ll wind up with defaults that may or may not be correct.

The CPU and serial interface: Another cool thing about the Printrboard: Unlike many ATMega based 3d printer controllers that came out at that time, the ATMega AT90USB1286 has native USB support. This will prove to be a double edged sword but won’t stop you from having fun with this board, read on. A Marlin build bug may show up when you’re trying to build as a result of this unique platform target. This is currently fixed in the nightly “bugfix” branch, so start from that if you are compiling Marlin yourself.

There is a “BOOT” jumper next to the chip. If you jump this and press the reset button, the chip will come up in DFU mode. It comes stock with a bootloader from Atmel that supports their FLIP utility for programming under Windows. (Todo: figure out what tools would be needed for this on other platforms.)

Dealing with Windows Being A Stupid Doodiehead As Usual: To program this chip, download Atmel FLIP and install it. On Windows 10 64-bit, get the version with the JRE included (as documented here). Tip the Printrbot over on its side and place a jumper cap on the BOOT pins, then press the reset button. You should see Windows detect the AT90USB in DFU mode— however, it may not properly install the driver. Open FLIP and click the USB cable icon in the toolbar, then choose USB connection. If you receive a message about a missing DLL, close FLIP again, and go into Device Manager. Right click the DFU device that’s showing up with a warning icon and choose Update Driver, then manually choose the location. The driver will have been dropped in C:\Program Files(x86)\Atmel\Flip [version]\usb. It should install ok, then Flip is ready to use.

To flash a file with Flip, go to File > Load Hex File. Click the USB plug icon and select USB connection. It should identify the AT90USB1286 if the chip’s already up in DFU mode. By default the options on the left will all be checked except Blank Check. That works fine… make sure it’s set to write out the Flash space and not the EEPROM space (the button in the top center toggles this), then click start at the lower left. It’ll take about 15 seconds to complete. IN THEORY, you should be able to reset out and run the newly programmed application in the chip with the button at lower right, but that doesn’t work for me – probably because the BOOT jumper is still set and it just loops back into DFU. Pull the jumper and press reset, and Windows should detect the

I have provided two compiled versions here at the end, one for printers with a heated bed and one for those without. The version for printers without a heatbed bed will work fine on those that do, you just won’t be able to heat the bed. The other way around, I suspect, would make it refuse to work with a MINTEMP error being thrown.

Building Marlin: I used PlatformIO and the Build Marlin addon tool. You can also use the Arduino IDE after installing Teensyduino. (Board type will be Teensyduino++ 2.0!). My configuration files are at the end of this post; my changes were mostly to invert the inductive probe output behavior (which MAY have been different for Rev. D boards!) and to add bilinear bed leveling with a 16 point probe. I tried using the new Unified Bed Leveling architecture but it caused the code size to exceed available memory. Bilinear is working fine on the machine here, so I’m just using it 🙂

Yes, you can buy that funky UBIS hotend and parts for it. The distance between the nozzle and probe center-to-center is 25MM, I’ve checked this and included it in the configuration file.

I have a sneaky suspicion that the example configurations for Marlin 2.0 just haven’t been touched since shortly before/after(?) Printrbot blinked out of existence and the example was only built and tested for the Rev. D Printrboard. A bit of searching around online suggests that the big change between D and F was the addition of a buffer transistor for the input from the inductive probe, which was prone to damage on Rev. D. If you have Rev. D, the stock config should be fine, but I think the buffer basically inverts the input. The way to tell will be to try homing the printer with G28. If the Z axis rises, pauses, then rises again, but never comes back down, use M119 to test the endstop input states. If the Z axis is not at the bottom and the LED on the proximity sensor is out, it should not say TRIGGERED for the Z endstop. Place a metal object under the probe so its light comes on and check again, it should say TRIGGERED. If you get the opposite behavior, you will need to toggle that state. The relevant lines are #define Z_MAX_ENDSTOP_INVERTING and #define Z_MIN_PROBE_ENDSTOP_INVERTING. These must match or it will toss an error on compilation.

Verification and Final Settings: Once you have the firmware loaded and running, open your terminal of choice. You can use Pronterface, the G-Code terminal in Octoprint, RepetierHost, whatever works.
Send M115 to get the firmware version.
If you previously had an older version of Marlin installed, send M502 then M500 to load the defaults from the firmware to the EEPROM space and save them. If this printer had an LCD (it CAN be added!) it would prompt you to do this from the front panel on first boot.
PID autotune: I usually start the fan first with M106 S255. This may not be necessary but I find it helps on some platforms.
Start the tuning routine with M303 S215 C8 U1
(8 cycles to 215 degrees C, and the U1 flag will save the values to RAM)
M500 to save the results to EEPROM for later use

Bed leveling: If you have a heatbed, heat it first to a normal use temperature (say, 50C for PLA) and let it stabilize a minute before continuing. The hotend temp won’t matter for now as it’s not going to affect the inductive probe.

G28
(this will auto home all three axes)
G29
(a magical dance will begin)
If you already have a working Z probe offset value from your old settings, enter it now
M851 Z-0.7 this will vary by your printer and build surface
M500

Once G29 is done, it will output a small table of the measurement values. Save the results with M500. Re-home with G28
Test the Z height by heating the hotend to a normal use temperature, placing a sheet of paper on the bed and sending G0 Z0. It should kinda just grab it. If you need to adjust it, check these instructions.
If your extruder is stock, well…. for the FIRST TIME EVER… and that is to say I have literally NEVER seen any other Chinese printer I’ve worked with factory calibrated correctly…. YOUR E-STEPS ARE PROBABLY CORRECT!!! See, this was why you paid extra for a Printrbot. Thing’s hardcore. If you want to verify/calibrate, go here. Otherwise it should Just Work.

this ‘tiny house’ trend is getting ridiculous

If you have Rev. D and these binaries don’t let the printer home right, let me know – I don’t have that version to test on and I’m curious about that probe behavior…

Download:
Printrbot-Simple-Metal-Marlin-Config-And-Binaries

Of cats, sticks, and ignoring instruction manuals

Gingy would like to remind you every time is the right time for petting your feline assistants.

Muddy little face and all
Good meowing! Today’s weather is going to be sunny with chance of bööps.

The cool looking radar is sadly no longer in use. Anyway, as for the title, we’d been having issues with the big transmitter here for months and it just wouldn’t run on all three cabinets. Its intermediate power amp had been giving issues on one cabinet and our other engineers had been over the manual and talking with tech support for months, it just wouldn’t make wattage.

This thing has vacuum tubes AND fecking JAVA. Run. Fast. And far. Run.

Finally the solution was to not trust the manual. It said the arbitrary “IPA Gain” number was supposed to be between 100 and 450. It was set on 100 and that led to only 9 watts drive to the IOT tube — 150 was needed. The solution in the end was … set the gain to about 520 or so. Amusingly, it only raised up from 9 watts once I went past 420.

420 blaze it

One of the other engineers had this Printrbot Simple Metal that he hadn’t gotten working so I took it back to play with it through the boring Thanksgiving morning shift. Despite it being a SOLID chonker, the carriage plate was bent up causing the hotend to hang at a weird angle, and some screws were loose or incorrect, so I fixed that and got it extruding. The only thing I wasn’t able to do which bugs me was to get a bootloader onto the Printrboard in there and load it with a newer version of Marlin supporting mesh bed leveling. This one is old and appears to take no parameters to G29 – it probes only three points. Weird. I couldn’t get Atmel’s FLIP utility to work and had issues with building Marlin for that particular cpu — it seems like you either have to use the toolchain for the Teensyduino++ or use PlatformIO, neither of which wanted to cooperate. Thus, it remains on old firmware.

Unless you’d actually miss those 1725 watts of heat.

Photo by EdwardX

A while back I noticed, hey, we’re actually using a…. plurality…. of 2000 watt halogen Fresnel fixtures in our studio. I brought up to the network’s one lighting guy that I’d found this cool (literally!) VisionSmith ReLamp System that includes a 275 watt tungsten lamp colored drop-in replacement for the CYX lightbulb… and can apparently also let you use acrylic Fresnel lenses which increase the fixture’s output even farther. He gave me this look like I’d just waved a dead skunk in his face, so I dropped the subject on the spot. Oh well, someday we’ll be able to explore MODERN technology 😉

So I’d mentioned this to someone in a thread on Facebook who got sticker shock seeing that the LED CYX replacement costs $945.25 from one vendor. The halogen CYX costs $30 (surprisingly, that’s a little less than the common HPL bulb used for Source Four lamps). I immediately thought to myself the total cost of operation must be VERY VERY much lower so I ran some back of the napkin numbers on it. These do not include the cost of air conditioning to remove the waste heat from the space as I don’t know how to calculate that off the top of my head. This is just for the bulb cost and electricity cost:

Average US electricity cost: 13.19 cents/KwH.

Rated life of the VisionSmith module: 50K hours
Rated life of the CYX halogen: 300 hours

Cost of electric power to run CYX bulbs for 50K hours: $13,190
Cost of 167 bulbs (!): $5010
Total cost of operation: $18,200

Cost of electric power to run the VisionSmith for 50K: $1814
Cost of one module: $945.25
Total cost of operation: $2759.25

Yeah—- I’m pretty sure which one I’m gonna go with.

Mystery Station Guide Vol. 1

Papa November

Come join us for mysterious yet uplifting and entertaining coded messages! 7404 kilocycles.

Papa November
66014 66014 66014
216 71 216 71 1234567890
60710 04206 22322 99433 10710 22599 42069 77307

*drags floppy disk to trash*

Sometimes 1990s file footage can be….. amazing

* no carrier *

C H O N K T A P E

It actually relieves me that we don’t have a deck for this

Incidentally, the ‘virus’ seen here was just a joke program and was not destructive, according to the SOT following these pictures on the tape.

DVCPRO archival transfer fun

I feel spoiled. I use DV video tape equipment sometimes and none of my stuff ever gives any issues. It just works. My stuff is Sony, Ikegami, and a couple of consumer grade mini dv camcorders. Every camera’s tape works in every other deck, dropouts are minimal and usually happen in the first second or two of rolling so if you preroll for “speed” it’s fine. My Sony DSR-1500A will even read DVCPRO media, though I’ve never tried it. Maybe I should?

Our station used to have a bureau down south in another city. This station had a 3-deck a/b roll editing system using DVCPRO. This was in service until about 2008 when everything was switched to HD when the network bought it and actually spent money on the station, unlike Shitclair which owned it in the past. Anyway, they had over 300 tapes of file footage there which were mostly dubbed on this one deck. The time finally came to get this footage transferred to the current digital archive system in use.

I’d been warned that DVCPRO tended to have alignment and timing drift issues that cause tapes to not interchange freely between equipment unless it’s all been field aligned to work together. So, thus, I tried the deck they were recorded on. First thing I found was a filthy transport, so I cleaned it up and replaced the little roller that cleans the video heads on load/eject. Please note in the picture above that there are two heads on the drum – the small interconnect boards just link the two heads to the rotary transformers.

Failure. The deck had severe picture breakup trying to play anything back.

I talked to one of my more experienced coworkers who told me to stop there and use a better deck. See, this 450 series, these were the cheap seats in the DVCPRO bowl. It didn’t even dawn on me until then that the 2-head deck is just not common! My consumer grade DVCAM stuff tends to have four or even six. I opened up one of the nicer decks and found four – it uses a finer pitch head for playback, making it even compatible with the narrower tracks of consumer DV! Also, uh, my decks are in good condition and not packed with 12+years of dust.

Clearly it’s time to deploy superior firepower, which is to say, the cybergoth falls and the air compressor….

Ok, time to get serious about reviving some old forgotten crap.

I want to appropriate the content of these for vaporwave purposes

These decks were known for having terribly bad capacitors; before the great Capacitor Plague and Samsung’s current habit of putting out lots of home electronics with crap caps, Panasonic put out a lot of gear that needed dozens of crappy smt electrolytics changed….. some on boards like this

Oh ok uh wait uhhhhh no no no no what the no the whole thing is just aaaaaaaaaaaaAAAAAAAAAA

I’m gonna go hide now ok

*possum noises*

Finally… After hours of work I got three decks up and running and they all read the tapes from the other bureau fine! I did wind up having to revise the cabinet using brute force and power tools though because the Evertz Video Passport turns out to double as a nice space heater and almost roasted itself once I started rolling video from the 3/4″ deck through it. It needed lots and lots of ventilation. The DVCPRO decks aren’t much better about that but at least they have forced front to back airflow.

The most perplexing moment of all this was when I had one deck working great then I ejected the tape and looked back inside and found the pinch roller lying in the bottom! What the heck? I just replaced it. I don’t know.

More colorful shitposting

The thing around my hair is not a ferrite core. It’s more like a slap bracelet and it’s awesome. It keeps the tail from just lying on the back of my neck.

The big hoop is an old TV/monitor degaussing coil and the box is what it came in. Don’t confuse this Jif with that other Jif. I don’t think either rhymes with Gif. Also, one of my coworkers gave me that beautiful blue hair dye, it’s from the Manic Panic line and I love it.

Channel condition: partly cloudy
Cute lil’ dvcpro transport in need of a dental cleaning
The Smurfhair roller was pretty filthy

Thankfully I don’t have to really do any major overhaul work on these — we have the tooling in house to do it, including PCs loaded with custom software to perform certain adjustments (yikes!) and these decks don’t even speak plain English to you like my Sony DVCAM stuff does… you have to have The Fine Manual in front of you because everything is just by numbers with no text labels in any of the menus! Hurrrrrrrrrrrrrrrrrrrrrrrrrr

The Silliest Voltmeter Ever…

The year…. something like 2004.

The transmitter…. Harris Broadcast PowerCD, a funky Inductive Output Tube based system with modular architecture supporting multiple cabinets.

The silliness: much. Much, much silliness. So here’s a hilarious one: this board is right at the power input to each cabinet and watches for power supply phase loss and provides voltage metering outputs. Power in this case is 480v 3 phase delta and the metering circuits on this card measure the voltage between A and B, B and C, and C and A. The measurement circuit is uhhhh the CACA type. 😉

This Got Hot. The resistors’ markings bleached out from the heat!

So, here’s what you’re looking at. The three resistors are 15K ohm 3 watt and are wired in series with R27 (a PTC 0.15 amp polyfuse device) and the sensor coil inside that LEM current sensor.

The LEM LV25-P sensor is a Hall effect current sensor with galvanic isolation. It accepts 0-10mA and puts out a sense voltage proportional to the current input.

The resistors are dissipating 3.84 watts total on each phase, well within their rating. However, this rating was not assuming they’d be piled up like this and crammed on a board stuffed in an unventilated space in the cabinet!

The end result of this was that one of the voltage readings constantly jumped around and caused false alarms to fill the alarm log…. while we were trying to diagnose another issue.

Note the power reading at the top– that was the Other Issue. Ow. Signal go down the hoooooooole.

I’m entirely confused as to why such a roundabout approach was taken to this when a set of isolation amplifiers with one side being powered off a voltage divider or even a small transformer on each phase would have worked with less bill of materials cost and less heat, but uh

we’re still at the bleeding edge of this technology

Don’t be upsetti, print some spaghetti

It’s…. pretty well acceptable that the sock falling off was the cause of this silliness. It’s so ridiculous I can’t even be mad.