Smiths Graseby 3200, Technical & Service Manual

Page: 51 / 117

Smiths Medical International Ltd.
3200 Service Manual Issue 5 (August 2004)
4 — 8
Setting RV1
The procedure for setting potentiometer RV1 is as follows:
1. Switch off the external AC power, remove the pump’s power connector and open the
casing (see page 2-11).
2. Remove plug PL11 and PL12 from the Regulator board and connect a 68 ohm, 1 watt
resistive load across pins 2 and 3 of plug PL11. Pins 2 and 3 are the two middle
pins on the connector.
Note:
A Molex connector ( part number 0053-0658 ) enables the 68 ohm resistor to be
easily connected to the pins of PL11.
Setting RV1
WARNING
Only a qualified technician may carry out the following procedures. With the
case open, dangerous voltages are present when AC power is applied.
3. Connect and switch ON the AC power. If necessary, adjust RV1 to give a DC voltage
across the 68 ohm load, dependent on the temperature, as shown in Table 4.3.
RV1 is located near the bottom left hand corner of the board (see
Figure 7.8 ).
Table 4.3 Temperature/voltage range for setting RV1
Ambient Voltage across
temp. (deg. C) load (volts)
28 7.015
27 7.027
26 7.038
25 7.050
24 7.062
23 7.073
22 7.085
21 7.096
20 7.108
19 7.120
18 7.131
17 7.143
16 7.154
15 7.166
4. Switch off the AC power. Remove the 68 ohm load and reconnect PL11 and PL12 to the
Regulator board. Assemble the casing (see page 2-11).