G540 Troubleshooting

This is intended to help users solve common errors with the G540. If you cannot get your G540 to work properly after following the steps in this guide, please contact technical support by clicking here.

Generally speaking, there are only a few number of reasons why the G540 will not function as expected. The most common are listed below.


SOLUTION: This is the most common fault and can be caused by several problems. First, double check that a jumper wire or normally closed switch is present between PIN 10 and PIN 12 on the 12 POSITION TERMINAL BLOCK. Next, turn the CHARGE PUMP SWITCH to the OFF position; if the green LED comes on then there is a problem with your CNC program not putting out a charge pump signal on PIN 16. If those do not work, check the motor for holding torque; if you do not have holding torque move on to the next section. 


SOLUTION: Verify that your motor is connected to the G540 with the DB9 connector and that it is wired as it says in the motor’s datasheet. Check the LED indicators to verify that power is being applied to the G540. Lastly, make sure that you have an appropriately sized current set resistor. If there is not one present or it is grossly undersized you may have burned out your motor and it could be shorted internally. 


SOLUTION: Verify that the power supply is plugged in correctly to the 12-PIN TERMINAL BLOCK. If it is and power is applied with no LEDs being lit up, you have most likely had the fuse blow open. To check the fuse you must first remove the cover. The fuse is located by the 12-PIN TERMINAL BLOCK on the underside of the motherboard; you can pull the motherboard off of the G250 drives to access it. Next, use an ohmmeter to check for continuity on the fuse, which looks like a green 1/4W resistor. If the fuse it destroyed you may contact Geckodrive for replacement fuses or order spares online with part number F23118-ND from 


SOLUTION: This problem is most often caused by a problem with the parallel port or the parallel cable. Use an ohmmeter to verify that your cable is a straight through cable and not a crossover or a printer cable. Next, go into BIOS and make sure that your parallel port is set to EPP or “Send/Receive” mode. If your parallel port is on your motherboard and is not a PCI card then the problem could be that it is incapable of EPP operation. Use a PCI parallel card and see if the problem persists. 


SOLUTION: The G540, being a stepper drive, is meant to get warm. While operating at its maximums the G540 can get up to 70C (158F) comfortably; heatsinking is mandatory if the temperature gets above that range. On the Geckodrive website is a document titled “G540 Heatsink Experiment” that discusses issues of overheating. If the G540 is in a control cabinet or an area with limited airflow it is required to put an intake and exhaust fan in the enclosure. Please read the cited document if you have further questions.