Mainboard¶
TriGorilla V_4.0.1 (Stock)¶
The stock mainboard is the "TriGorilla V_4.0.1".
It's a 32bit 24V mainboard with a GigaDevice MCU labeled as "GD32F303" which seems to be an ARM Cortex-M4 with 120MHz, 512K flash and 64K SRAM.
It offers a microSD card reader, a USB-C connector and a 10 pin connector for adding the control unit.
The mainboard comes with TMC2208(?) silent stepper drivers soldered onto the board (so they can't be just swapped out!).
The microSD card reader slot and the USB-C connector can be accessed from at front of the printer, you find them at the right hand side of that black plastic aperture of the frame as shown in the picture below.
Add Ferrules To The 24V Wires!
It's highly advisable to cut off the soldered tips of the wires without a plug (power supply and heated bed) and add ferrules to them.
When you are screwing down the soldered tip inside the clamp, the solder will get cracked a bit and may get deformed a bit as well. When the wire gets warm due to the current and the solder gets softer, the contact may become loose which could lead to malfunction or even cause fire in the last consequence. So it's always a good idea to just use proper ferrules.
Avoid Shortcuts!
Shortcuts coming from the cartridge heater for example can/will damage your mainboard, so be careful to never cause a shortcut somehow!
A common misbehaviour is to clean the nozzle with a little brass brush during the print process or while everything is heating up.
Also grabbing the heater block to e.g. change the nozzle while everything is heating up and electrical current is flowing is another common mistake.
When using pliers to hold the heater block, the tips of the pliers may touch the contacts of the wires at the cartridge heater and you cause a shortcut. As a result you can/will get blown up part at the mainboard, like the melted part "D4" for example as shown in the picture below.
So always turn off the whole printer first to avoid a shortcut which will destroy your mainboard!
Use A USB Power Blocker
When connecting the printer to a computer or a Raspberry Pi, it is highly recommended to use an additional USB power blocker.
By doing so, you make sure that neither the computer nor the mainboard will draw power through the USB-C connector from the other device. If you don't do so, it can harm your mainboard as well as your computer.
As it's an fast and easy solution, you can get a device called "USB power blocker" for a few bucks. Attention: make sure to not get a "USB data blocker" though, it has to be a power blocker!
This device will then be plugged between the USB connector of the computer and the actual USB-C cable. It still allows data to be transferred, but the 5V line isn't existent. The following pictures show such a device and how it's installed.
However, you don't have to spend money on this item, as there are other ways to interrupt the 5V power line. For example, you can cut the 5V wire of your USB cable, you can solder a male and a female USB connector onto a little PCB and avoid making the 5V line connection or you can simply use some electric or Kapton tape and cover the belonging pin at the USB connector of the cable like shown in the following picture.
Keep in mind though that you have to pay attention that you only cover the 5V pin and that you have to make sure that the tape is still in place every time you plug in the cable after you unplugged it.
Red Glue Across All Connectors
When you look at the mainboard, you'll see some red glue spread across all connectors. That's just for securing the connnection. You can get that stuff off by carefully pulling it off. It works better if you warm up that stuff a little bit for making it more flexible, a hair dryer is good for that. It then becomes a bit softer and easier to be pulled off. Don't heat it up too much though as it'll become too soft then!
You can also use a thin screwdriver to lift up a part of that stuff and then use some tweezers to grab it.
However, be very careful to
- not harm the mainboard by slipping off with the screwdriver or tweezer!
- not overheat the mainboards of parts of it when heating up that red glue!
- not rip off the heatsinks of the stepper drivers!
This can happen really quick as they're just glued onto the stepper drivers with some thermal paste and the red glue is usually spread across the fins of the heatsinks as well!
So if you have to pull off that stuff from those connectors of the motor wiring, then make sure that you press down the heatsink with your finger when trying to pull that stuff off!
Mainboard Cooling Fan¶
The following picture shows the fan of the mainboard. It's a 70x70x15mm, 24V, 0.08A type ("Coolcox CC7015M24S").
MOD: Different Mainboard¶
It's possible to replace the stock mainboard with a different type of board, like e.g. a board from BigTreeTech (BTT). You just have to pay attention that it uses and provides 24V DC as well, as the PSU and the components like the fans etc. are running on 24V. Depending on the type of the board, you might have to use a different ABL sensor (and most likely a different type of control unit as well though, but I assume you'll run Klipper on it then anyway).
MOD: Add An External MOSFET¶
It's advisable to add an external MOSFET for driving the heated bed (if you like, you can also add one for the heater cartridge as well of course). Even though the MOSFET on the mainboard is sufficient, it's an upgrade worth doing as it not only leads to the fact that the bed will be heated up slightly faster, but it also increases the security of the hole printer.
The MOSFET of the mainboard doesn't have a heatsink and it may caused by overheating due to an excessive amount of current being drawn, especially when using higher bed temperatures. Due to the low clearance between the fan of the moainboard and the ground the printer stands on, the cooling isn't the best as well. When using an enclosure which then heats up as well, cooling gets even worse.
If the board's MOSTFET dies, you most likely have to get a whole new mainboard then. Even though it's possible to solder a new one onto the board (if you're skilled to do that), additional components might have been harmed.
To avoid that, it's therefore adviseable to add an external MOSFET which then takes the load - the one on the mainboard only acts as a signal for the external one to switch.
The 24V DC of the PSU will be connected to the belonging connector of the external MOSFET. The 24V DC line from the heated bed screw terminals will be connected with the belonging connector of the external MOSFET and the 24V DC wires of the heated bed will then be connected to the outlet of the external MOSFET. When the mainboard switches the onboard MOSFET, it will then trigger the external one to switch and lead the current to the heated bed.
There are a few external MOSFETs on the market, most of them only have a "signal" connector. When using a mainboard with a dedicated 'signal' connector for this, it's then connected to that one. When using a mainboard that doesn't have this 'signal' connector like the one being used at these printers, then it's said to connect the 24V from the bed's connector of the mainboard to that.
I personally prefer a certain type of MOSFET which also offers a dedicated connector for the 24V line besides the 'signal' connector as shown in the following picture.
The PSU and the wiring of the bedplate are connected to the belonging connectors shown in the following picture: 24V from the PSU belongs to the connector labeled as "Power", the 24V for the wiring of the bedplate belongs to the connector "Hotbed".
The 24V of the bed's connector of the mainboard will then be connected to the belonging connector "Bed" at the MOSFET (positioned next to the connector labeled as "Sig").
If you're using this kind (or a different kind) of MOSFET, you should check if the manufacturer actually added some thermal paste between the MOSFET and the heatsink - it wasn't the case at the ones I got as shown in the picture below, so that actually completely counteracts the whole installation and makes it obsolete.
Mind The Polarity
Pay attention to the polarity when connecting the components!
Add An Additional Fuse
It is highly recommended to add a suitable fuse to the 24V line, right after the connector of the PSU. If your additional parts like the converter will fail, the fuse will melt - which can save you from burning down your house.
The following picture shows the MOSFET being mounted to the rear left-hand side of the frame. I made an extension wire for the thermistor wires as well.
As an additional benefit, now that it's mounted back there, the problem with the bed's wires being too short isn't given anymore.
MOD: How To Add A Step-Down Converter For Using 12V Fans¶
When you want to add components which need a different voltage than the 24VDC the PSU offers, you can do so by using a step-down converter (or a step-up converter if you need a higher voltage than 24VDC). Simply connect the IN of the converter to one of the free 24VDC connectors of the PSU, dial in the voltage you need and then connect the belonging part to the OUT of the converter.
The following picture shows a typical "LM2596S" type step-down converter which can be used.
However, when you want to use e.g. 12V fans which speeds are usually controlled by PWM of the mainboard, you have to connect them differently. The following drawing shows how to proceed in that case, so that the PWM will still work.
Warning
The following circuit diagram about how to connect a step-down converter wasn't tested by me yet. It's assumed that the mainboard controls the PWM of the fans by switching the belonging GND of the connector.
Add An Additional Fuse
It is highly recommended to add a suitable fuse to the 24V line, right after the connector of the PSU. If your additional parts like the converter will fail, the fuse will melt - which can save you from burning down your house.
MOD: Add Additional Fuses To The 24V DC Wiring¶
It is highly recommended to add a fuse or a fusebox to each of the 24V lines. Pay attention to choose the correct 'size' of the fuse for the belonging part (ampere rating).
Doing so can save you from burning down your house if components fail or if the wires somehow overheat and start to burn due to broken strands (which causes a higher resistance) or a shortcut.
(..need to add pic..)