celesco PT420 Replacement Instructions - Page 2
Browse online or download pdf Replacement Instructions for Transducer celesco PT420. celesco PT420 4 pages. Measuring cable
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MEASURING CABLE REPLACEMENT
1.
Remove the two #4-40 screws from the top of the cover and set aside.
2.
Gently lift off the cover. There are still wires connected between the rotational
sensor in the unit and the cover; be careful not to force or pull too hard. If the
cover is stuck use a twisting motion. Carefully work the cable end through the
cover hole and set the cover aside.
3.
Remove the two #8-32 screws from the baseplate of he transducer and set aside.
4.
Remove baseplate and set aside.
5.
If the cable is still intact and can be extended and retracted, proceed with step 6.
Otherwise, skip to step 20.
6.
There are two set screws offset 90 degrees holding the spool to the potentiometer
shaft. While looking through the access hole in the frame, extend the cable so one
of the set screws can be seen.
7.
With an allen wrench, loosen the set screw.
8.
Extend the cable again until the other set screw is visible and loosen the set screw
9.
Grasp the potentiometer and its mounting plate and pull straight out of the spool.
The screws and spacers on either end of the mounting bracket don' t have to be
loosened or removed.
10.
Check potentiometer for damage. If cable has been free-released or broken, the
potentiometer may be broken. Turn the potentiometer shaft all the way in both
directions. If the transducer is a 2 inch or 5 inch range, the shaft should rotate
smoothly with no resistance. If the transducer is a 10 inch or greater range, the
shaft should rotate smoothly with no resistance until it suddenly stops. If rough
spots, resistance, or "soft" stops are felt, the potentiometer is damaged and must
be replaced. Contact Celesco for new potentiometers and replace if necessary.
11.
Extend the measurement cable a short distance and cut it with a pair of wire
cutters.
The spring motor can be dangerous while it has tension. The spring, if allowed to, can
suddenly uncoil itself by shooting out of the spring housing. It' s sharp and can cause
injuries. Be careful when doing anything with the spring exposed. Wear gloves and
safety goggles.
12.
Loosen the #8-32 screws holding the spring housing. If the spring still has
tension, when the bolts are removed the spring housing will spin. Get a firm grip
on the frame and spring housing, remove the bolts, and set aside.
13.
Carefully let the spring housing rotate until all spring tension is released, while
keeping the housing against the spring side plate.
14.
The spring is probably still hooked to the spring arbor. BE CAREFUL TO NOT
pull the spring housing off yet or the spring may shoot out of the housing.
15.
Separate the spring housing from the frame just enough to get a flathead
screwdriver between the housing and the spring side plate.
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CAUTION