Gaymar MEDI-THERM II MTA5900 Series, Руководство по обслуживанию

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SERVICE MANUAL
Medi-Therm II THEORY OF OPERATION
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BACKUP SYSTEMS
Backup systems within the Medi-Therm II machine limit the temperature of water
exiting the machine to specified ranges in the event of a failure of the control
system including the microprocessor:
Maximum water temperature is limited by two bimetallic thermostats. If
either of these two thermostats is actuated, a REMOVE FROM USE NOW /
MACHINE SHUTDOWN circuit is triggered which:
• shuts down the pump and heater;
• lights the ALERT and the REMOVE FROM USE NOW / MACHINE
SHUTDOWN indicators; and,
• sounds the audible alarm.
In addition, if the microprocessor is operational, the compressor shuts down, the
displays blank, and the
ALERT indicator and audible alarm turn on and off.
Minimum water temperature is limited by a bimetallic thermostat. If this
thermostat is actuated, a REMOVE FROM USE NOW / MACHINE SHUTDOWN
circuit is triggered, which in turn:
• shuts down the pump and heater;
• lights the ALERT and the REMOVE FROM USE NOW / MACHINE
SHUTDOWN indicators; and,
• sounds the audible alarm. In addition, if the microprocessor is
operational, the compressor shuts down, the displays blank, and the
ALERT indicator and audible alarm turn on and off.
See figure 8, p. 67 for base-to-head and control/display board-to-power supply
board connections; figure 18, p. 79 for system wiring diagram; figures 19, 20 and
21, pp. 80, 81, 82 for the electrical schematics; figures 22 and 23, pp. 83 and 84,
for component layouts and part designations; and figure 24, p. 85 for the
control/display board block diagram.
CONTROL/DISPLAY BOARD AND POWER SUPPLY BOARD
The Medi-Therm II machine uses two printed circuit boards (see figure 8, p. 67):
• The control/display board contains the microprocessor circuits, the
display circuits, and all other low voltage control circuits.
• The power supply board contains the power supply, the low voltage
to high voltage interface circuits, and the
REMOVE FROM USE NOW
/ MACHINE SHUTDOWN backup safety circuits.
The control/display board connects to the patient probe jack J1 via P2 at J2
and to the digital control assembly panel via P4 at J4. All other connections
from the system’s peripheral devices to the control/display board are made
through the power supply board.
A 26-pin cable connects the control/display board via P1 at J1 to the power
supply board via P3 at J4.
6.1 THEORY OF
OPERATION,
MEDI-THERM II
MACHINE (continued)
6.2 SYSTEM
COMPONENT
INTERCONNECTIONS
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