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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goes into a shutdown condition it also sends an output signal from port pin
P3.4, through U40 of the control/display board, to command, via Q11, U4, and
U6 on the power supply board, a
REMOVE FROM USE NOW / MACHINE
SHUTDOWN condition. The process of turning off the heater and pump triacs
Q3 and Q4 by the microprocessor removes power from the REMOVE FROM
USE NOW / MACHINE SHUTDOWN circuitry on the power supply board
which then allows the indicators on the control/display board to toggle under
microprocessor control. This shutdown condition by the microprocessor
program will remain until the machine is powered down. If, upon machine turn
on, the fault condition still exists, attempting to resume therapy (which would
turn on the pump and possibly heater) will replace power to the
REMOVE
FROM USE NOW / MACHINE SHUTDOWN circuits on the power supply board
and cause the REMOVE FROM USE NOW / MACHINE SHUTDOWN condition to
recur.
Also, if during normal operation, the microprocessor senses internal
problems, it will attempt a shutdown as described above. (See table 2, section
8.1, p. 35.)
If the microprocessor is nonoperational at the event of a signal from Q10 of
the power supply board, the user is notified of the
REMOVE FROM USE NOW
/ MACHINE SHUTDOWN condition by the fact that the above mentioned
indicators are on continuously. In addition, there are separate, redundant
circuits on the power supply board, each triggered by any of the thermostats,
that insure that the pump and heater remain off even if the thermostat cools
sufficiently to close again. The
REMOVE FROM USE NOW / MACHINE
SHUTDOWN condition remains latched and can be cleared only by an operator
intervention in the form of turning the machine circuit breaker off. If, upon
machine turn on, the fault condition still exists, attempting to resume therapy
will cause the
REMOVE FROM USE NOW / MACHINE SHUTDOWN condition to
recur.
6.4.7 BACK-UP WATER
TEMPERATURE
LIMITING
(continued)
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