FuelChamber Toolhead PCB

This is a drop-in remix of hartk's Afterburner Toolhead PCB v3.1 with the following changes:

• On-board 12V regulator to allow the operation of 12V fans, selectable for each fan using solder jumpers. Maximum 1A for the 12V rail.
• Pin Compatible with the Afterburner Toolhead PCB
• Decreased height to avoid interference with the Voron 1.8 gantry
• Increased clearance for the mounting screws to avoid damaging the traces

Rev A and Rev B have no support for the BAT85 Diode!

Usage

This PCB replaces a hartk Afterburner Toolhead PCB. Replace your 24V fans with 12V fans as needed, and use the solder jumpers to configure the voltage. Simply remove the old PCB and insert this one.

For assembly: Always start with the lowest height components and work your way up.

Note this PCB is experimental because it has yet to be determined if the DC/DC converters survive the constant toolhead movements. Although the VR10S12 did survive for 100 printing hours now, it's unlikely that they fail, but we never know until we try.s

BOM

Warning: Outdated!

Designator	Footprint	Value	Remarks
C1	1206	10µF 35V	ceramic caps are okay, too
CT	0805	CMFB103F3950FANT	10kΩ ±1% 3950K NTC Thermistor
D1 (for VR10S12 )	SMB	22µF 16V	use a 1206 capacitor, 10µF ceramic is often okay, too
D1 (for R-78C12-1.0)	SMB	1SMB5928BT3G	as specified by the R-78C12-1.0 datasheet
DC1	SIP 3	VR10S12	The original design used a Recom R-78C12-1.0, but a XP Power VR10S12 is cheaper
LED1	0805	LED 0805	Use any 0805 chip LED, indicates heater activity
R1	0805	see remarks	Calculate this appropriately for LED1 and 24V!
HE0, HEF, PCF, XES	JST-XH-02	2-pin JST XH
ABL	JST-XH-03	3-pin JST XH
E-STEP	JST-XH-04	4-pin JST XH
HE0	MOLEX 436500200	MOLEX 436500200
-	MOLEX 430451400	MOLEX 430451400

Alternative Voltage Regulators

You can use one of these DC/DC voltage regulators if you are having trouble finding the VR10S12. Please refer to the datasheet for any input/output decoupling.

Please do not use any linear voltage regulators, because these require a heatsink and the acceleration forces will most likely shear off the voltage regulator over time.

1A DC/DC Converters

• Traco Power TSR 1-24120
• Recom R-78C12-1.0

500mA DC/DC Converters

Use these only if you are sure that your fans will not exceed the current capability! The peak current when the fans are starting up can be higher than specified!

• Aimtec AMSR-7812-NZ
• Traco Power TSR 0.5-24120
• XP Power SR05S12

Design Notes

• The trace widths are calculated to allow operation within a 70°C chamber and a maximum temperature rise of 10°C.
• The pin assignments of the 14 pin MicroFit3 connector is unchanged
• The original version used a Recom R-78C12-1.0, but has been changed to a VR10S12 which lowers the cost significantly
• I've been using the Rev.A with a VR10S12 for about 100 hours of printing in conjunction with a single 12V fan, no issues observed so far