Another Z-Axis End Stop For Geeetech A10

Once the power situation was improved to something more acceptable, I revisited the Z-axis end stop. Because the bare wire hack attached with tape was never going to cut it long term.

The first order of business was to transfer the circuit to a small circuit board instead of just wires hanging in the air. This little board was broken off from a larger prototype board, an easy task as the board was already perforated. The inexpensive switch I used (*) had two mounting holes that conveniently lined up to holes on the perforated prototype circuit board, so I soldered two pins at those locations as primary load bearers. I pushed the switch against those two pins as I soldered the three signal pins, hopefully this means any downward force from the homing procedure would be directed into the two mounting pins and not the three electrical pins.

Geeetech A10 Z axis end stop clip old and new

Geeetech A10 Z axis end stop clip CADOnce I had a small circuit board to hold the switch wired to the appropriate JST-XH (*) 3P (3-pin or 3-position) connector, I designed and 3D printed a small bracket to hold it to the machine. I saw no signs of how the original Z-axis may have been fastened, certainly no obvious holes to reuse. So I designed a clip-on bracket. The tool-less installation is a plus, but it came with the downside that it could not grip solidly enough to reliably hold a Z-axis position.

Right now it is sitting at the bottom against a cross beam, sitting at a height that I had guessed is relatively close to the original Z-axis end stop switch position. If that is too high, I will either have to print a shorter bracket or take a knife and trim some of the bottom off of this one. If it is too low, I can add something underneath this bracket to act as a spacer or print a taller bracket.


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Replacement Power Panel for Geeetech A10

A very crude Z-axis end stop switch allowed me to verify this partial chassis of an old Geeetech A10 could still move in the X, Y, and Z axis. Once proven, I went back to refine the hacks done in the interest of expediency for those tests. First task is the power adapter, which had been a cheap barrel jack not quite the correct dimensions for reliable electrical contact with the 12V DC power adapter I’ve been using.

The 12V supply itself was a hack, as the Geeetech A10 printer is actually designed as a 24V printer but I didn’t have a 24V power brick handy. Since this printer has been deprived of its print nozzle and heated bed, the majority of power draw are absent leaving only the motors. I understand the stepper motor current chopper drivers would still keep the current within limits and give me nearly equivalent holding torque. However, halving the voltage meant it couldn’t sustain as high of a maximum speed and I saw this on the Z-axis. The X axis is super light (as there is no print head) and had no problem running quickly on 12V. The Y axis has to move the print bed carriage (minus heated print bed) and had a little more difficulty, but still plenty quick. So it was the Z-axis that ran into limitations first, as it had to push the entire carriage upwards and it would lose steps at higher speeds well before reaching firmware speed limits that are presumably achievable if given 24V.

Geeetech A10 power panel CADA reduced top speed was still good enough for me to proceed so I drew up a quick 3D printable power panel for the printer. Since the 12V DC power supply was from my disassembled Monoprice Mini printer, I decided to reuse the jack and the power switch as well. Two protrusions in the printed plastic fit into extrusion rails, though it took a few prints to dial in the best size to fit within the rails.

With this power panel I could use the 12V DC power adapter and the connection is reliable. No more power resets from jiggled power cables! It also allows me to turn the printer off and on without unplugging the power jack.

With this little power panel in place, I moved on to build a better Z-axis end stop.

Crude Z Axis End Stop For Geeetech A10

Preliminary exploration of a retired Geeetech A10 has gone well so far, enough that I felt confident discarding the control panel I did not intend to use. Before I tossed the control panel in a box, I verified each of the motors could move via jogging commands. But before I can toss more complex commands at the machine, I need a way to reset the machine to a known state. In machine tools this is called a “homing” operation, and this 3D printer do so via the G28 Auto Home command to set each axis to their end stop switches.

Problem: While the X and Y axis still had their respective end stop switches, this machine is missing the Z-axis switch and I wanted to whip up a quick hack to test the machine capabilities. If it works, I’ll revisit the problem and spend more time on a proper one. If it doesn’t work, at least I haven’t wasted a lot of time and effort.

The existing X-axis end stop was buried inside the mechanism, but the Y-axis end stop is visible. I was surprised to see a circuit board with several surface mount components on board. Unlike most of my other 3D printers, the end stop mechanism isn’t just a pair of wires hooked up to a single switch, there are actually three wires.

Geeetech A10 Y endstop

I removed the Y-axis switch to probe the circuit and search online. It appears to be close but not quite identical to the RepRap design, and had a few additions like a LED and its associated current-limiting resistor. The LED is a nice indicator of switch toggling status, but it is not strictly necessary. This end stop boiled down to a switch that directly connects the normally open leg to common, and a resistor between the normally closed leg and common.

Once understood, I grabbed a micro switch waiting in my parts bin (*) and created a free form wire soldering job for the test attached with double sided foam tape. (Picture up top.) The foam tape did not hold position well enough, so additional structure support was added in the form of blue painter’s tape.

Geeetech A10 Z endstop hack with tape

Hacks upon hacks, it’s hacks all the way down.

But it was good enough for G28 Auto Home to succeed, which opened the door for more tests to verify this 3D printer chassis could still execute motion control commands coordinated across all three dimensions. Once I was satisfied it is working well enough for further tinkering, I revisited the power hack to make it more reliable.


(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

Geeetech A10 Control Panel Removed

Once I had the retired Geeetech A10 3D printer powered up, I could start poking around to see what is working and what is not. Obviously the control panel was my entry point to jog each axis. I was very happy to see the individual motors move on command, but I couldn’t command a homing cycle just yet due to the missing Z-axis switch.

However, the control panel itself was annoying to use. The screen contrast was poor, and user responsiveness is lacking. I frequently find that encoder steps were ignored, as were some of my wheel presses to select menu options. I experienced the same frustration with the Monoprice Maker Select, and I had thought those issues were specific to that printer. Now I’m starting to wonder if this is common with 3D printers running Marlin on a ATmega328 control board.

The good news is that I don’t plan to interact with the control panel for much more than this initial test. Once I established the board was functional, I no longer feared the USB port damaging my computer so I found an appropriate USB cable and plugged it in. The expected USB serial device showed up. With the popular settings 250000 8N1, I could command the printer via Marlin G-code. This is how I intend to control this machine as a three-axis motion control platform.

I didn’t intend to use the control panel anymore, and I could have just left it alone. But it also sticks out to the side of the printer and awkwardly taking up space. After a particularly painful meeting between a body part and an outer corner of the panel, I took a closer look at how it was connected to the control board. It seems to be a single ribbon cable plugged into a single connector that had two dabs of hot glue to help keep it in place.

Geeetech A10 control panel ribbon cable connector

I removed the hot glue and the cable to see if this printer would continue functioning as a USB serial peripheral, in the absence of the control panel. Good news: it does! I could move all three axis (X, Y, and Z) via G0 commands. So after removing two M5 bolts, the control panel go live in a box. Cleaning up the printer outline and hopefully reducing painful episodes in the future.

Now I need to install a replacement Z-axis homing switch in order to try homing cycle.

Power Input Replacement for Geeetech A10

I’ve received the gift of a retired Geeetech A10 3D printer. It is missing some important components for 3D printing, but its three axis motion control components are superficially intact. The machine is in unknown condition with no warranties expressed or implied. Ashley Stillson, the previous owner, don’t remember everything that was wrong with it, but she did not remember anything dangerous. (My specific question was: “Will I burn down the house if power it up?”)

Not burning down the house was a good baseline, so I’ll begin by supplying the machine with some power to see what wakes up. The first task was to replace the XT60 power connector. The XT60 isn’t a type I use and hence I had nothing to plug into it. This type is an excellent connector for high current draw applications, but since I’m not planning to run a heated print bed nor a filament nozzle heater, I can start with something less capable and more generic. So instead of buying some XT60 connectors (*), I replaced it with a jack for a barrel plug (*) that I already had on hand.

The cheap jack I have on hand is listed with outer diameter of 5.5mm and inner diameter of 2.1mm. It is very close but not exactly the correct type to connect to the 12V DC power supply from my disassembled Monoprice Mini printer, which I guess is actually the very similar and popular type 5.5mm OD / 2.5mm ID. But what I have is close enough for a little hacking to permit power to flow.

Later I learned I had made an assumption I didn’t even realize I was making at the time: I assumed the printer wanted 12V power. The Geeetech A10 is actually a 24V printer! This is irrelevant to the electronics, which will run on stepped-down voltage probably 5V. It is most important for the heater elements, which are absent anyway. In the middle are the stepper motor subsystem, where 12V is not ideal leaving them less capable than if they were fed 24V, but they should function well enough to let me evaluate the situation.

When power was supplied, a fan started spinning, a red LED illuminated, followed by the control panel coming to life. We are in business.


(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

Retired Geeetech A10 3D Printer

My herd of 3D printers has gained a new member: a Geeetech A10. Or at least, most of one. It was a gift from Ashley Stillson, who retired this printer after moving on to other machines. Wear on the rollers indicated it has lived a productive life. Its age also showed from missing several of the improvements visible in the product listing for the current version. (And here it is on Amazon *)

In addition to those new features, this particular printer is missing several critical components of a 3D printer. There is no print head to deposit melted plastic filament, it has no extruder to push filament into the print head. The Bowden tube connecting those two components are missing. There is no print bed to deposit filament on to, and there is no power supply to feed all the electrical appetite.

It does, however, still have all three motorized axis X, Y, and Z, and a logic board with control panel. X and Y axis still had their end stop switches, but the Z axis switch is absent leaving only a connector for the switch.

Geeetech A10 Z endstop connector

The only remnant of the power supply system is a XT60 plug. I don’t use XT60 in my own projects and have none on hand, so I will either need to buy some (*) or swap out the connector to match a power supply I have on hand.

Geeetech A10 XT60 power connector

It would take some work to bring it back into working condition as a 3D printer, but that’s not important right now because my ideas for this chassis is not to bring it back to printing duty. I’m interested in putting its three-axis motion control capability. to other use. But first, I need to get its three axis moving, which means giving it some power.


(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

And Now I’m Up To (Most Of) Five 3D Printers

When I first got started in 3D printing, I was well aware of the trend for enthusiasts in the field to quickly find themselves with an entire flock of them. I can confirm that stereotype, as now I am in the possession of (most of) five printers.

My first printer, a Monoprice Select Mini, was still functional but due to its limitations I had not used it for many months. I had been contemplating taking it apart to reuse its parts. When I talked about that idea with some local people, I found a mutually beneficial trade: in exchange for my functioning printer, I traded it for a nearly identical but non-functioning unit to take apart.

My second, a Monoprice Maker Ultimate, has experienced multiple electrical failures with an infamous relay, and I suspect those failures had secondary repercussions that triggered other failures in the system. It is currently not working and awaiting a control board upgrade.

My third printer, a Monoprice Maker Select, was very affordable but there were trade-offs made to reach that price point. I’ve since had to make several upgrades to make it moderately usable, but it was never a joyous ownership experience.

Those three printers were the topic of the tale of 3D printing adventures I told to Robotics Society of Southern California. One of my parting advise was that, once we get to the ~$700 range of the Maker Ultimate, there were many other solid options. The canonical default choice is a Prusa i3 and I came very close to buying one of my own several times.

What I ended up buying is a MatterHackers Pulse, a derivative of the Prusa i3. I bought it during 2019’s “Black Friday” sale season, when MatterHackers advertised their Pulse XE variant at a hefty discount. Full of upgrades that I would have contemplated installing anyway, it has performed very well and I can happily recommend this printer.

Why would I buy a fifth printer when I had a perfectly functioning Pulse XE? Well, I wouldn’t. I didn’t get this printer because it was better, I picked it up because it was free. I have some motion control (not 3D printing) projects on the candidate list and a retired partial Geeetech A10 printer may prove useful.