Product

• Trendsetter^® 400/800 — MCE
• Trendsetter NEWS — MCE

Machines affected

MCE devices - serial numbers start with TM or NM

Component

TSM engine

Error

• Warning:
  PLL possibly losing lock! Error = xxx.xxx um (xx clock cycles)
• Error:
  PLL lost lock! Error = xxx.xxx um (xx clock cycles)

Symptoms

The warning indicates that a problem occurred in the PLL but the error is not large enough to abort the plot. Imaging will continue. The error is unlikely to be detected in the image because it is small.

If the error continues and becomes larger, it eventually passes a threshold and the image is aborted. When this happens, the lost lock error message is displayed.
Note: The specific value where the plot aborts may change from device to device and in different versions of firmware.

Cause

Possible causes include:

• Incorrect drum belt tension
• Loose setscrews on the encoder
• Incorrect encoder position
• Incorrect drum NVS parameters
• Excessive runout of the drum drive motor pulley (i.e., the amount the pulley moves in and out away from its true center as it rotates)

Solution

1. Use a BRECOflex meter to check that the drum belt tension is 70 Hz.
   You can order a BRECOflex meter from you regional office.
   Note: On Trendsetter AL and Trendsetter NEWS devices, it is critical that this belt tension be set correctly. Field approximation methods are not adequate to measure this tension.
2. Check that the setscrew(s) on the encoder shaft are snug.
3. Check the position of the encoder in the mounting slots.
   The encoder must not be mounted at the extreme end of the mounting slots.
   If the encoder is mounted at the extreme end of the mounting slots, reposition the encoder as shown in the photo.
   
4. Check that the drum NVS parameters are at the default values.
   The drum NVS parameters should not be changed from their default values unless instructions to do so are received from product development.
5. If, after you have performed all of the above steps, the PLL lock warnings or errors persist, try replacing the drum motor pulley. (A field replacement kit for the pulley and taper-lock bushing will be posted on this page shortly).
   
   Note: The only practical way to determine in the field whether the drum motor pulley has excessive runout is to replace it and see if the PLL lock warnings/errors stop. However, this is an expensive and time-consuming action, and should only be done after all other possible causes of the PLL lock warnings/errors have been eliminated.

See also

• Adjusting the drum drive motor belt tension (MCE, toothed belt)
• Shaft encoder alignment procedure (TS4/TS8)

Technical contact(s)

Doug Jeffery

Submitted by

Doug Jeffery

Date submitted

29 Jul 2004