mark 7 stalls, blinks

[Sherm]

I bought a Mark7 from the original owner who bought from the factory in 2016. It seems in excellent shape. He never had a problem with it. I used it several times with no issues. Now it stops turning shortly after I press "On". The display shows some message and then goes blank and proceeds to blink off and on. None of the controls change this response. It goes on forever—unless I pull the plug. Then it continues blinking for about 10 seconds without power. This implies a capacitor someplace is discharging through the display. I am thoroughly puzzled.  If I wait a while and then plug it in, it might start and might not. What happened and how can I fix it?

[DLB]

The display staying on for a bit after removal of power is normal for a PowerPro. Generally it should give a normal display, then switch to a LOW VOLTAGE message, then go blank. The message yours is displaying when it first stops turning might be useful in determining the fault. If it isn't on there long enough to read, try doing a video recording of the display so you can provide that information.

There are three major replaceable components of the PowerPro: the motor, the display/control panel, and the power supply / controller. It is difficult to isolate the fault among these three in most cases, but the failure message may offer some insight. The power supply / controller seems to have the highest failure rate.

Note: turning off the headstock main power switch should do the same thing as unplugging the unit. This is not Off/On on the control panel but a physical power switch above the display.

IIWM, my first step would be to capture the fault message(s). My second would be to remove the lower belt so the motor is not driving any load and see if there is any change in behavior. This isolates the motor from a possible mechanical overload, such as a seized bearing, elsewhere in the headstock. You can report results back here. Also if you provide your location someone in your area might be able to help you with fault isolation.

- David

[Adityuhn]

I bought a Mark7 from the original owner who bought from the factory in 2016. It seems in excellent shape. He never had a problem with it. I used it several times with no issues. Now it stops turning shortly after I press "On". The display shows some message and then goes blank and proceeds to blink off and on. None of the controls change this response. It goes on forever—unless I pull the plug. Then it continues blinking for about 10 seconds without power. This implies a capacitor someplace is discharging through the display. I am thoroughly puzzled.  If I wait a while and then plug it in, it might start and might not. What happened and how can I fix it?

Hi Sherm!
Your Mark7 may be experiencing power problems, most likely due to a capacitor or voltage regulator circuit that has failed after a long period of use. Symptoms such as continuous flashing, the display then turning off, and unresponsive controls are often related to an unstable power source. You should check the power supply, capacitors on the control board, or contact the manufacturer for support to replace components. If the machine is old (since 2016), this is a common error due to component degradation.

[JPG]

One thing about aluminum speed control parts is they do not degrade over time.(wear excluded!)