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5700A/5720A Series II Calibrator
Service Manual
5-24
3406 A13: 8255 Port B
The diagnostics software reads port B of the 8255 IC on the Oscillator Output assembly
during the instruments dormant state. A failure indicates the Oscillator Output assembly
(A13) is probably at fault.
3407 A13: 8255 Port C
The diagnostics software reads port C of the 8255 IC on the Oscillator Output assembly
during the instruments dormant state. A failure indicates the Oscillator Output assembly
(A13) is probably at fault.
3408 A13: Fixed Ampl. Osc Fault
The instrument is set for 1V ac at 100 Hz, 1 kHz, 10 kHz, 100 kHz, and 1 MHz. The
signal line INTEGRATOR OUT on the Oscillator Output assembly is measured via the
SDL line. Each frequency range is tested at the fixed 1V amplitude. INTEGRATOR
OUT is measured to be 0V ±1V at the lower three frequency ranges, ±2V at the 100 kHz
range, and ±5V at the 1 MHz range. A failure indicates the Oscillator Output assembly
(A13) is probably at fault.
3409 A13: Phase Lock Loop Fault
The instrument is set for 1V ac at 100 Hz, 1 kHz, 10 kHz, 100 kHz, and 1 MHz. The
signal line LOOP FILTER OUT on the Oscillator Output assembly is measured via the
SDL line. Each frequency range is tested at the fixed 1V amplitude. LOOP FILTER
OUT is measured to be 0V ±5V. A failure indicates the Oscillator Output assembly
(A13) is probably at fault.
3410 A12/A13: 22V Amp Bias Adj Error
The instrument is set for 1V and 10V at 1 kHz operation. Signal line AMP1 on the
Oscillator Output assembly is measured via the SDL line. A failure indicates that AMP1
was measured to be greater than 500 mV but less than 2V. A failure indicates the
Oscillator Output assembly (A13) is probably at fault. Check the zero adjustment of
potentiometer R30 on the OSC SMD AMP assembly.
3411 A12/A13: 22V Amp Nonfunctional
The instrument is set for 1V and 10V at 1 kHz operation. Signal line AMP1 on the
Oscillator Output assembly is measured via the SDL line. A failure indicates that AMP1
was measured to be greater than 2V. A failure indicates the Oscillator Output assembly
(A13) is probably at fault.
3412 A12 To A13 Interface Fault
The instrument is set for 1V 1 kHz operation. Signal VREF on the Oscillator Control
assembly (A12) is measured via the SDL line to be 3.16V ±100 mV. A failure indicates
the Oscillator Control assembly (A12) is probably at fault.
3413 A12/A13: 14 Bit DAC Nonfunctional
The instrument is set for 1V 1 kHz operation. Signal 14 BIT DAC OUT on the Oscillator
Control assembly is measured via the SDL line. The 15 bit DAC circuit on the Oscillator
Control assembly is set for outputs of 0V, -1.58V, and -3.16V, and is measured to be