Manual

Installation and Maintenance Manual

Chapter 8: Troubleshooting

NOTE: Field repair beyond this level is not recommended.

8.1: Preliminary Checks

Check all system wiring connections at the transducer and at the programmer. Amphenol-type connec-

tors on the transducer and its cabling should be checked for tightness. A slight tug on all wire termina-

tions should verify a good connection. Push-on cable connectors should be checked for proper con-

nections. Verify that incoming AC voltage to the 1995 PLS is between 105V AC and 125V AC.

The following procedures are intended to aid in isolating system malfunctions to field replaceable

modules. These modules include the 1995 programmer, output relays, remote circular display, trans-

ducer, and all interconnecting cables. Once isolated, the defective module should be replaced and

returned to the factory for repair.

8.2: Transducer Excitation Voltages

AC voltage across terminals 2 (RH) and 3 (RL) of the 16-place terminal strip (labeled Red and BK/R)

should be from 1.6 to 1.9V RMS. This is the output voltage being supplied to the resolver rotor. If this

voltage is not present, disconnect the resolver wires at the 1995 programmer and recheck the voltage.

If this voltage is still not present, the resolver excitation circuitry in the 1995 programmer has failed and

should be replaced. If this voltage appears, a shorted condition in the resolver or its cable should be

checked.

The return signals from the resolver stator windings are wired to the 1995 programmers 16-place

terminal strip at terminals 4 and 5 (labeled White and BK/W), and terminals 6 and 7 (labeled Green and

BK/G). To verity the presence of these AC return signals, put a voltmeter across terminals 4 and 5 and

rotate the resolver. A voltage reading that rises and falls (0-2.3V RMS) between these terminals as the

resolver is rotated indicates a good resolver return signal. Repeat this same procedure with your meter

across terminals 6 and 7. No voltage or a voltage that does not vary as the resolver rotates indicates an

open or shorted condition in the resolver windings or the resolver cable.

To check for an open or shorted condition inside of the resolver, disconnect the Amphenol-style con-

nector from the transducer and make the following checks at the resolver: Measure the resistance

across Pins A & B (rotor); it should measure approximately 19-50 ohms. Then measure across Pins C

& D (stator); it should measure approximately 50-120 ohms. The resistance across E & F should be

the same as C & D.

NOTE: Due to the many different types of resolvers that we have used over the years, these

resistance readings are only approximate and are intended for locating opens or shorts in the

resolver wires or windings.