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Tools Needed:
•
Phillips or Flat Blade Screwdriver
•
7/16" Socket or adjustable wrench
•
Ohmmeter
•
DC Voltmeter
•
AC Voltmeter
•
5VDC Power Supply
When changing circuit boards, please use
CAUTION when re-installing the flat cable
connectors that come from the display board.
Make sure the pins are NOT bent or broken. Boards
that are otherwise fine will not operate correctly if
these pins have been abused because they will not
receive the necessary signals from other boards.
Before attempting any troubleshooting for a
particular problem, it is good practice to verify
power supply voltages of the POWER SUPPLY
board #3176677. Read these steps before
performing them to get acquainted with the
procedure.
1. Be sure that the main power source is OFF or
disconnected.
2. Connect J101 and J105 to the POWER
SUPPLY BOARD. DO NOT connect J102
that comes from the CPU and the DISPLAY
at this time.
3. Connect the negative lead of the voltmeter to
TP2 - COM. Select a VDC of 20. Connect the
positive lead to TP1 - UNREG.
4. Turn ON the main power.
5. The voltmeter should be reading approximately
14 volts DC ±2.
6. Connect the positive lead to TP3 ±5V. The
voltmeter should be reading +5 volts DC ±0.5.
7. Turn OFF main power.
8. Connect the display board ribbon connector to
the power supply board at J102 and then
repeat steps 3 through 6. Do not connect the
connector to the CPU board at this time . If the
above voltages are not measured again, the
display board has a bad component which is
loading down the voltages. If the voltages are
still present, continue on to step 9.
9. Connect the display board ribbon connector to
the CPU board J310 and repeat steps 3 through
6. If the above voltages are not measured
again, the CPU board has a bad component
which is loading down the voltages. This
board will have to be replaced.
GENERAL INFORMATION:
SUPPLY PCB ASSEMBLY #3176677 has the triac
(solid state AC voltage switch) on it which supplies
the power to the heater. This triac is "told" to
operate, when need be, by the microprocessor.
There is another device known as an opto-coupler
which serves as the high/low voltage isolator
between the triac and the microprocessor.
When the bath starts experiencing temperature
problem and/or variations, due to known controller
malfunctioning, these two components become
prime suspects. The reason being they are under
higher operating stress than other components.
If the bath starts experiencing temperature problems
such as no heat, or "creeping" upward heat, then
follow the troubleshooting instructions below.
These instructions require the use of a voltmeter
being able to measure DC and AC voltages
(preferably digital) and an ohmmeter.
WARNING
THE FOLLOWING TROUBLESHOOTING
INSTRUCTIONS REQUIRE THAT POWER BE
ON. ONLY QUALIFIED SERVICE PERSONNEL
SHOULD PERFORM THESE PROCEDURES.
8
The POWER
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