Last Summer, I was given two 3D Printers in a stash of Vintage Computer hardware (Old 8-bit). One 3D printer is a Monoprice Ultimate and the other is a Prusa i3 a602 DIY kit—LseeStudio Printer.
Initially the printers where not the primary focus of the acquisition. The Monoprice Ultimate worked without any effort so it was immediately thrown into service with my other 3 - 3D Printers. (Artillery Sidewinders (X1 & X2), another Monoprice (I3)).
The LseeStudio printer was shelved as it appears to not have been completed or assembled fully. Maybe it was disassembled but I am leaning more toward not completed as some of the winding pipe was still not cut off and there are multiple feet hanging extra off the sides of connected wiring. There are also numerous (most) wires not connected and the belts were not finalized (rough cut). The unit was also very dirty from being on a shelf in a pole barn for a extended amount of time.
During the LseeStudio printer’s travel, it appears to have also suffered a thermal bed PCB pad separation.
I have included some images of Main Board/heat bed;
I have cleaned the printer. The main board and PSU powers up and it appears to function.
I am looking for help/suggestion on the following;
Connecting the wiring to the control board. There are some markings on the PCB but not seeing which are for the servos (assuming top row). The thermistors are not fully identified (T0,T1,T2 but which ones are which) The limit switches are two connectors where the control board have 3 pin for the X,Y,Z max. The center row/pins are ground, The other two rows which should represent signal and 5 volt are measuring 5 volts.
Finalizing the belts - I bought new belt with clamps but I also have the one original.
Getting this thing printing - I see a USB B connector. Not sure if this works similar to the other 3D Printers I own or if there are O/S drivers or am I missing a connector work with a USB stick?
Any documentation for this printer I would be very greatful. Also any suggestion on what to do with the heat bed? I do have soldering skills and equipment but I question the best approach (rewire, repair or a replacement) as that part is under strain/movement?
With the right USB connector, you can connect it to your computer and use something like Octoprint to talk to it. Pretty common to use a raspberry pi or similar for something like this today. I don’t see an sd or microsd card on there.
I’d just connect thermistors and touch them with my fingers and see which one changes reading to identify the thermistor ports. Similar for limit switches.
Solder makes stranded wire break, so you are smart to want to affix it mechanically somehow to reduce strain. You’ll need high heat to get a good solder joint because that is a heat sink; the solder joint might have been cold and failed for that reason.
I would cut off the parts of the wire that have wicked up solder, add crimp ferrules, and solder the ferrules to the board, to avoid wicking solder into the stranded wires.
You may consider checking whether you see support for this board in modern Marlin — but without the original firmware that might be a one-way trip.
If you ultimately can’t get this control board going, there are plenty of inexpensive 32-bit control boards that you can hook up instead of this control board, if you still want to use the rest of the hardware.
I am familiar with Raspberry Pi boards and have them all over my residence. I have not done anything with them in the 3D Printer Realm. I know that is a real possibility and definitely something to consider. Not done much with Octoprint but my sister has a small 3D Printer Farm for a small home business and uses it extensively.
From my additional reading last night it appears that this board does support Marlin. There was an article that said Marlin 1.9.1 is suggested as the later releases had some issues. Whether that was a “snapshot” of that time period (web posting year) or still has issues I am not sure 100%. Your mention of the original firmware does complicate matters and Initially I will focus on just get it running first, if possible, on the original firmware. I did see other people requesting the original firmware in other forums…so hopefully someone posted it.
The thermistors should be wired as T0 for the hotend, while T1 or T2 can be used for a heated bed. I guess this is some standard, I was not aware of, in electronics but it seems to match another board I own instructions. Also seems to have water also in the solar industry.
This forum posting might change into, or I may create another, a Marlin step by step as I did not have to much luck with Marlin in the past. It was not changing the #define or C files as I am a developer (28 yrs) and actually coded in C++ for close to a decade at Microsoft. It was more with the values needed for the actual printer/setup.
My one Artillery Sidewinder X1 was heavily modified by the previous owner (sister) and at the time had a series of issues (hardware). I got the hardware cleaned up and working but never updated the Marlin version. I have printed quite a few things on it successfully but my main 3D printers are the Artillery Sidewinder X2 (stock) and the Monoprice Ultimate(stock).
On the hotbed, both solder connections I question. The one still attached looks like its weak (cold solder) and just plain messy. The other, I believe ripped the pad from the board but I am not 100% sure the orientation of the wiring is even correct. Not sure also if someone tried to fix it or not. I am also curious could I just use one of the other pads on the hot bed? I am looking for a wiring setup (documentation) for the hotbed.
I like the idea of crimp ferrules for the connection points. I know I have a few in my lab but I probably will have to order a bunch more.
Do you know the connections or where there might be documentation for this specific hotbed at 12V and/or the 24 Volt setup? I believe these beds were modeled by there Mkx associations…(ie MK2, MK2a. MK2b, MK3).
Most I have seen cross one of the pins with another and then one wire (V+) goes to the cross over and the other to ground.
I am just wondering if changing the connections around somehow would make the hot bed usable at 12V. (Possibly using the other “side”/”internal section” of the hot bed - the other 12V Side?) I probably could correct the lifted pad but the previous approach is probably much faster/stronger.
I ordered a 2000 kit of crimp ferrules from Amazon and they should be here tomorrow.
I was more saying that since the other pads were probably for 24V, you probably couldn’t use them and are probably going to have to get access to the 12V trace.
You can measure resistance at the terminals.
P=IE (Power law) and E=IR (Ohm’s law). E and R being constant, I=E/R, and substituting in gives P=E^2/R. So if you send half the voltage to the terminals (12V to the 24V terminals) you get one quarter the output power.
Anyway if I were trying to revive this, I’d be scraping off resist and adding solder to try to make something reliable, and I’d temper my expectations for longevity…
I have the X,Y, and Z Rails to the point they appear working. The extruder gets to temp. Unfortunately the bed still has some issues.
The largest of them appears to be no voltage to the bed. I added the crimp ferrules to everything that did not.have a finish connector. Amazon was delayed an additional day for the crimp ferrules.
I have tried to preheat the bed to 60 degrees. I did not connect the hot bed to the mainboard but just took a reading inititally with my DMM at the mainboard connection. I am not getting voltage at the main board for the bed nor once I connected everything at the final connector end either.
I have confirmed both 12v connections from the PSU to mainboard.
The mainboard has the hotbed connection labeled. I do question a couple unlabeled connections….one in particular (unlabeled) that has 12v potential and is a decent connector. I am still unable to locate much on this printer as far as documentation.
Not sure if all this is the reason the original owner abandon the project or some other scenario?
Also, Not entirely sure what options I should look into now. The printer is further along but now appears to need a possible mainboard setup and new hotbed for good measure. The hotbed appears obtainable for a very reasonable amount. Considering this printer is at least 10 years old it might be one to consider to disassemble. Thoughts?
Honestly, I disassembled my old i3 clone for parts years ago. The control board and display I repurposed to run my home-made filament drying oven. I’ve used various pieces of it for different things over the years.
I am kind of wondering if that is the same direction I should take with this 3D Printer. My feeling overall is this thing will end up being a shelf queen more than anything else. Not to mention my quality out of my Monoprice I3 was never super terrific (even with Upgrades). Especially compared to my Monoprice Ultimate or my Artillery SideWinders.
We will not to mention my wife has been considering a new (multicolor) 3D Printer. The i3 was good for its time. In the end price will probably decide the overall fate of this unit.
So some more testing this morning led me to confirm that the ground side is handling the switching. The one side of the bed circuit does have 12 Volts. I am assuming there is a MOSFET under the heat sink (Green Square Below) handling the switching mechanism.
Further, the Red area is the main boards hot bed LED which is not luminating when things are switched to heat the bed. The LED does luminate under my DMM Diode testing. The purple color squares represent the fact that the 12 volt from the bed comes directly from the 12 volt input from the PSU. The yellow squares represent that the one side of the bed LED goes to the ground side of the output (connector) or simply the wiring heading to the hot bed.
So I am wondering if under that heatsink there may be a fuse or did I just blow out a MOSFET. Looking that area over closer, its clear, they were very concern about temperatures in that area of the board. The PCB is vented entirely under the green area. Unforunately not much can be seen or tested further till the heat sink is removed.
Anyone have any ideas if the mainboards are commonly fused for the hotbed circuit?
With all this said/explored, I am still actually undecided at this point.
Thigns could become a interesting electronic correction or maybe I could find another donor board either from a new option from Temu, eBay, or Amazon…Any Suggestions - seems $20→$40 could go a long ways? Or maybe I can locate a worse off unit…This weekend is one of our larger local area HAM Radio Festivals/Sales.
It’s been a few years since I’d had to troubleshoot a hotend or heatbed but the standard practice of the design is to switch the 12V negative with the FET so 12V positive would be wired to the bed V+ connector and the HEATBED FET connection would be to the V- of the heatbed.
So to troubleshoot you would wire everything up, power up and make sure you can measure 12V(or 24V) between your powersupply ground and the V+ on the heatbed. If you don’t get 12V there then go back to the connector on the board to see if you get 12V there.
Once you know you have 12V between the PSU GND and the V+ on the heatbed, look for 12V back at the FET/HEATBED connector. It should read 12V(between PSU-GND and HEATBED) only when the heatbed is not turned on. If all that checks out and you turn on your heatbed but don’t see your HEATBED to PSU-GND voltage go to 0V then either your FET has failed or your firmware is not setup to control the correct pin of the FET.
As you have said the MOSFET Drain and Source would be handling the negative/ground/V- side. The MOSFET Gate is probably flipped by the 5 Volt Rail on the board. I say 5 volt as I see a LED on the board that is luminated showing 5V and another for 12V.
I just, as a exercise, confirmed things as you have said. If I measure from the hot bed connection(s) at the hot bed…I get 0 Volts (final point on the bed). I measured from the same connection at the positive to the PSU V negative I get 12 Volts. This would confirm the Positive Wire to the Bed fully and the PSU is putting out 12 Volts.
The measurement is the same whether the Hotbed is engaged or not. So this also confirms that the voltage is being controlled on the negative/ground side/V-.
If I measure the same bed connection (positive) to the connection “leaving” the main board I get 0 volts. If I measure the PSU connection coming in to the Main Board (V-) I get 12 Volts. This correlates to what I am seeing and you are saying the MOSFET controls the ground/neutral/V- side of things. Unfortunately that appears to be where the problem resides (at the board/MOSFET).
If I could get that heatsink off without destroying the board there is some chance remaining I could correct/save the LSeeStudio original board. If not I would be in the market for a cheap replacement.
The hotend in this exercise is working properly it appears. It gets up to temp quickly. The extruder does not appear to have been used. The stepper motor appears to advance properly as well.
I am thinking tomorrow, if time permits, I am going to try and get the heatsink off which will have the board out of the 3D Printer and on the bench. I am going to try and see if the dental floss trick will allow it to pop off revealing what I am expecting is a series of MOSFETs. I can get out my hot air soldering station if necessary to loosen the epoxy but I am not wanting to heat things up if possible…to avoid damaging anything.
I am also going to price out a replacement setup (Temu for the mainboard/screen more than likely)….a new hotbed (eBay) to correct what probably started (a short - pad/solder joint released?) this issue in the first place for the original owner.
