38
Change the VA setting to 100, the TP4, CVA Module voltage is now 1.00 volts RMS; that at
TP8 is approximately 3.00 volts.
If operation is satisfactory to this point the Series 800 should be ready for calibration. The
remaining malfunctions could be in the shunt resistors R6, 7, 9 or 10 and K2, 3 or 4 of the
Output Relay Assembly. Replace AR3 Oscillator.
4.5.5 Suspected Phase Function Failure
Refer to Waveforms Figure 4-10 (08-800-002/3). Remove AR3 Oscillator. The voltage and
current will not be synchronized. Use an oscilloscope for tracing with external Synch. set on TP4-
Phase Control. Connect a short from current HI to current LO, and set 50Hz, 100V, 100W, 1 PF,
Lag, Operate. Observe the waveform at TP11, Oscillator, as a 10 volt peak sine wave. Examine TP3
Phase Control to be a sine wave with very sharp transitions from -1 to +1 volt and vice versa,
synchronized. Examine TP14 Phase Control to be a sine wave, not synchronized.
Examine TP6 Phase Control to be a pulse train, normally high, which changes in pulse width
and appears and disappears at the difference frequency between the two waves. A failure to achieve
this signal locates the malfunction in AR3, l4, IC2, 3 or 9.
Examine TP9 to vary from approximately -11 volts, and back, at the difference frequency.
Failure to achieve this signal locates the malfunction in U4, U5, AR6 or IC7, 8.
If the signal at TP9 is satisfactory the fault is located in the circuits of AR3, Oscillator.
Examine TP8, Phase Control, to be 0 VDC ±1mV. Vary Power Factor and observe the value at TP8
to vary as the function -10×(1-PF) volts. When LEAD is selected TP8 varies as +10×(1-PF) volts.
Failure to achieve these values locates the fault in U7, U6, AR7, 8, U8, 9, 10, 11, IC5 or +10V
Reference.
4.5.6 Line Synchronization Function Erratic
Please notice that this function is located on the Reference Assembly. This malfunction is
noticeable when the Series 800 is Operated in the line Synch. mode, the voltage amplitude may vary
and the voltage may intermittently try to synchronize to the line or run free. When the voltage phase
relationship to the synchronizing signal varies the current may also vary in amps as well as phase.
Operate with line Synch. in the ON (up) position. Remove AR10, Reference Assembly. Set
100V, 100W, 1 PF; select the frequency closest to line frequency; short the current HI-current LO
terminals and assert Operate. Use an oscilloscope to observe waveforms synchronized to the line.
Observe Reference TP5 as a square wave with TTL voltage levels. If otherwise, check AR8
and IC7 Reference.
Observe TP6, Reference Module, to be a pulse train of varying width, appearing and
disappearing at the rate of the difference between line frequency and the front panel selected
frequency. IC8 can cause a failure at this point.
Observe TP12, Reference, to vary from maximum positive to maximum negative voltage
(about +5 to -5); otherwise check AR9 or IC9.
Replace AR10 Reference Assembly. Setting as above, line Synch. switch on, (up). Observe
TP7, Reference, to be a small sine wave superimposed on +6V DC (approximately). See Step 18 of
Calibration Procedure.
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