Page 16 13900-103 Rev. A
Testing (Continued)
Test Point Voltages
The following information regarding the test points that are located on the circuit boards of this instrument are given as a
guide to verify the correct operation of the unit. If special operating conditions are required to observe the references
given, effort will be given to provide the necessary information with the appropriate references.
Power Input / Output Circuit Board (Assy 13960-925, Schematic 13960-915) Refer to Figures TT-1 & TT-2.
Test Points
TP1 = Test Point 1, +6 Volts peak (half wave) at 50 KHz.
TP2 = Test Point 2, –20.5 VDC (note: LCD screen must be ON). Refer to the Calibration section for voltage level adjustment.
TP9 = Test Point 9, +750 mVDC (note: LCD screen must be ON). Refer to the Calibration section for voltage level adjustment.
TP10 = Test Point 10, Signal Ground (0 VDC)
TP11 = Test Point 11, Vcc Ground (0 VDC)
Note: Pin 5 of the RS232 serial port is also Vcc Ground (0 VDC)
J4 Connector Header
Pin 1 = Vcc Ground (0 VDC)
Pin 7 = –8.0 VDC
Pin 8 = +8.8 VDC
Pin 9 = +8.8 VDC
Misc. Test Points
C60(+) = +15 VDC
CR10(–) = +18 VDC)
CR11(+) = –18 VDC)
CR12(–) = +Vcc (+5.0 VDC)
Y1 (pin closest to C9) = 8.0 MHZ Sinusoid
Voltage at F1 (main fuse on ckt bd) = 14 to 16 VDC
Main Control Circuit Board (Assy 13900-921, Schematic 13900-911) Refer to Figures TT-3 & TT-4.
Oscillator Outputs
Y1 = 16.0 MHz (approx 5.5 Vp-p Sinusoid)
Y2 = 3.69 MHz (approx 5.5 Vp-p Sinusoid)
Y3 = 32.8 KHz (approx 1.7 Vp-p Sinusoid)
J1 Connector
Pin B1 = Vcc Ground (0 VDC)
Pin B32 = +5.0 VDC, +Vcc
P1 Connector Header Jumpers
Pin 5 + 6, Watch Dog Disable (used for testing). Should not short pins 5+6 during normal operation.
(Jumper in = Disable, Jumper out = Enable)
Misc. Test Points
CR1 = Red/Green. Green = normal operation, Red = hardware failure or reset.
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