Welch Allyn Grason-Stadler GSI 17 1717-9700, Service Manual

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EQUIPMENT REQUIRED
Variable DC power supply, operating range of +6.5 Vdc to +7.5 Vdc
minimum DVM.
1. Adjust DC power supply to 7.5 Vdc then connect the negative
terminal to TP100 and the positive terminal to TP101.
2. Connect DVM to Audiometer Module TP1000 (LOW) and TP102
(HIGH).
3. Connect simulated battery input circuit to Audiometer Module
as indicated in Figure 4-3.
4. Power up the GSI 17.
5. Enter Diagnostic Mode (D3).
a)
Place Dip Switch S2 positions 1, 3, 4 to the ON
position.
b)
Place the Cal/Norm Switch to the Cal position.
6. The GSI 17 display will momentarily display D3, then will
update to a converted A/D value. Adjust the DC power supply
voltage to obtain 7.30 Vdc mV) on the DVM. Store the
new A/D value in memory by pressing the +10 dB Range
Extender Button. The display will momentarily display L1
indicating proper
storage of data into memory. (It is
important that the +10 dB button is pressed only once. If
L2 is displayed, exit Cal Mode, return to Step 5 and repeat
procedure.)
7. Adjust the DC power supply voltage to 7.0 Vdc mV).
Store this A/D value into memory by pressing the +10 dB
Range Extender Button. The display will momentarily display
L2 indicating proper storage of data into memory.
8. Adjust DC power supply to 7.5 Vdc. Place all Dip Switch S2
positions to OFF, and place Cal/Norm Switch S6 to the Normal
Mode position.
9. Slowly decrease the DC power supply voltage until the LOW
BAT indicator is displayed. This should occur between 7.25
and 7.35 Vdc. Continue decreasing the input voltage. The
display should blank at 6.95 to 7.05 Vdc. NOTE: To clear
the
LOW BA T
indication the unit must be returned to full
power and the power switch toggled.
After completing calibration and verification checks remove the
power supply and simulated battery input circuit and proceed with
calibration of transducers.