China CNC Episode 1: Bobs 3020 + 300W Spindle & Mini CNC Controller

Please first read the introduction
Bobs 3020:  
Seems the warranty didn’t ship with this one and the 100% satisfaction was also missing from the box.  
On first inspection of the control box we found the expected:
  • Inverted mains polarity on the 24V PSU – Cost Savings $0.00
  • No earthing on either 24 or 48V PSU – Cost Savings $0.50
  • Chassis wiring earthed to painted chassis – Cost Savings $0.05
  • No USB insight – Cost Savings $5.00 – not that it would have worked anyway.
  • No filter on fan and fan installed backwards –  Cost Savings $0.50
  • No limit switches or ports to connect limits switches. – Cost Savings $5.00

Total Savings: $11.05.  We assume bob would have paid the extra.


The Fix:

  • Corrected polarity on PSU input – ask your electrician to do this.
  • Earthed Chassis and PSU’s correctly – ask your electrician to do this.
  • Replaced dead 24V PSU – Buy local approved unit, ask your electrician to install
  • Inserted a GRBL AIO – conveniently the steppers generally use the same plugs and pinout so no wiring to do there.
  • Ripped out all electronics


Control Chassis Internal Image Before:

Control Chassis Internal Image After 


Parts for the Bin:


  • Couldn’t fix the fan as we do not stock this size filter cover.
  • Lost the 4th Axis as the AIO firmware ‘GRBL‘ supports only 3 Axis at this time. 
  • Could not find a wiring diagram so Bob will have to switch plugs around for X, Y and Z to find the right combination.
  • Now that the AIO is in there which will accept limit switches, Bob might want to buy and fit some

Cost :

  • Time: ~2 hours
  • AIO $105
  • PSU $45