PG7000 piston gauges have one of two drive systems to rotate the piston, mass bell and masses.
The original system was used until early 2006 with serial numbers up to about 430. It uses a solenoid motor to partially rotate a lever and pin which pivots the engagement clutch. This system is not recommend for use with Automated Mass Handlers.
The current system was implemented at that time with firmware version 2.07b. It uses a motor driven cam to rotate the clutch system in and out. A pair of micro switches are used with the the cam to start and stop the rotational movement. A failure mode of this system is for the micro switches to stop detecting movement. Often this is due to wear of the switch lever and a simple bending of the roller arm can help to extend the movement of the switch lever, thereby restoring the operation of the switch until a replacement can be installed.
Here's a video showing correct operation of the current system. Note how the engagement motor, lever and limit switches work. This video is with a PG7102, PG7202 or PG7302 piston gauge.
This next video shows what can happen when the switches fail. The symptom is typically seen as short spin time or the inability of the mass and piston to spin for more than a few moments. This video is with a PG7102, PG7202 or PG7302 piston gauge.
Here's the part number for a limit switch and related hardware for the current engagement system (in the above videos). Orders can be made to our Orders Team or by calling 1.877.355.3225
Limit Switch (Qty 2)
Part Number: 3141087
Description: (103362),SWITCH,SPDT,250VAC,4A,MICRO
Limit Switch Mounting Screw (Qty 4)
Part Number: 3154864
Description: (103662-Z),SCR,SS,BHSHC,M2 X 10
Lockwasher for Mounting Screw (Qty 4)
Part Number: 3154329
Description: (103288-Z),WASHER,LOCK,SPLIT,STAINLESS,M2
Retaining Ring on Limit Switch (Qty 2, or 3 for one extra)
Part Number: 3139165
Description: RING,RETAINING,DIN 471-003C BERYLLIUM COPPER
Washer, under Retaining Ring (Qty 2, or 3 for one extra)
Part Number: 3143059
Description: WASHER,FLAT,UHMW,NATURAL,0.250+-.005 OD X 0.126+-.005 ID X 0.005+-.002 THK
Linkage (Qty 1)
Part Number: 3150849
Description: 124231,LINK,PG ENGAGE,PG7000
See the linked documents below for common troubleshooting information. The fuse document is for PG bases with serial number up to 732. Newer models have a different main board. The other two files show how to check limit switches, engagement lever adjustment, etc. The "Newer drive engage TS 20181005 cust.pdf" file shows a PG7601 PG. Note that the PG7601 PG has the rotation electronics board visible next to the engagement system. PG7102, PG7202 and PG7302 PGs have this board underneath (have to remove the bottom cover for access).
Contact Fluke Calibration Pressure Technical Support at the below link or at 1.877.355.3225 if you have questions.