JEMM Frequently Asked Questions (FAQ)

Here are some common questions. Please contact us for more information.

What are your terms of payments?

Repairs are generally shipped open account Net 10 days. We also accept Visa and Master Card payments.

Do you repair any other type of electronic devices?

Yes, we are very interested in inquires and service of other electronic devices. Contact us, explaining what the device does along with any other information you may have of the product.

My tub works normally for a moment, but then it starts jerking or stops completely. Why?

Run the grinder at normal operating RPM in the auto mode. Check the voltage at the solenoid with a DC volt meter with the solenoid still connected. If the voltage is higher than 3 volts DC but the tub is not moving the problem is likely a sticking spool in the valve. Follow this link for information on how to disassemble and clean the valve. If cleaning doesn’t work, the valve will need to be replaced.

Why does my tub turn in manual but not in auto?

  1. Check sensor spacing by making sure there is a dime’s distance between the sensor and the sprocket. If spacing is OK, go to “2” below. If it isn’t, adjust sensor and try grinding.
  2. Disconnect the connector from the back of the box. Look for pin “B” and “C.” Start grinder at normal grinding RPM. Make sure there is at least 3 Volts AC between pints “B” and “C.” If there is go to “3” below. If there is not, disconnect at sensor and run rotor at regular grinding RPM. Check for 3 volts AC on the two posts of the sensor.
  3. If there is 3 V AC at sensor, the cable is damaged. Replace cable. If there isn’t 3 V AC at the sensor, replace the sensor.

Why won’t my tub turn in either auto or manual mode?

  1. Check the fuse on the control box. If fuse is bad, replace it. If it blows the fuse again, check for shorts in the wiring harness.
  2. Check to be sure power is getting to the box. Disconnect the cable from the back of the control box. Take a DC voltage reading between pints “A” and “B” with the grinder running at gringing RPM. Reading should be 12-14 volts DC for a 12 volt system, 24-28 volts DC for a 24 volt system. A much lower or higher reading could be a charging system problem or a bad ground connection. If proper voltage is present and the box dosen’t work, send the box in for repair.

What is the turn around time for repairs?

Typically, one to four business days plus shipping time.

Why doesn’t my tub turn?

Possible Causes:

  • Be sure battery is in good operating condition.
  • The cable is disconnected or damaged.
  • Check battery connections.
  • Be sure there is a good ground.
  • Check for any damaged ends.

If thhe sensor is out of adjustment:

  1. Check sensor spacing by making sure there is a dime’s thickness (1/16 inch) between the sensor and the sprocket.
  2. Disconnect the connector from the back of the box. Look for pin “B” and “C.” Start grinder at normal grinding RPM. Make sure there is at least 3 Volts AC between pins “B” and “C.” If there is not, disconnect at sensor and run at regular grinding RPM.
  3. If reading is O.K. at sensor, then check cable for damaged or poor connections.

What is your repair policy?

Each repair is evaluated from information received or collected by our testing to successfully regain control of your engine load. To find out where you need to send your control box, please visit the Servicing & Repair section of our website.