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Check these voltages prior to using the troubleshooting chart.
TP-6 is one lead of R27 and should be 2.00 VDC. The flow signals sent by flowmeters on
channels 1 - 4 can be accessed by test points on one lead of C7 thru 10 respectively in the left rear
of the main PC board. These do not have test point numbers, but their positions are screen printed
on the PC board.
4.2 Troubleshooting Chart:SYMPTOM: Display has no indication regardless of the position of the Channel Selector
switch and all TP voltages are 0.0VDC.
ACTION: Ensure the unit is plugged into an operating source of AC power of the proper
voltage for the unit. Remove the fuse from the back of the unit. Replace it with
a 0.5 Amp 250 volt fuse if it has failed.
SYMPTOM: TP-2 is 0, but TP-3 is correct.
ACTION: The positive voltage regulator (U1) has failed; replace it.
SYMPTOM: TP-3 is 0, but TP-2 is correct.
ACTION: The negative voltage regulator (U2) has failed replace it.
SYMPTOM: All Correction factors are approximately 0 or out of range.
ACTION: Check TP-6 (one end or R27). If this is not 2.00 VDC replace U3 (AD580
voltage reference).
SYMPTOM: Correction factors not displayed when CORRECTION FACTOR switch
depressed or the factors are displayed regardless of the postion of the
CORRECTION FACTOR switch.
ACTION: The analog switch (U6) has failed; replace it.
SYMPTOM: The decimal point is stuck in either the flow position or in the position used by
the correction factor.
ACTION: The decimal point analog switch (U8) has failed; replace it.
SYMPTOM: TP-3 and TP-2 are both low but non-zero.
ACTION: Check to see if the power supply source selector switch (S2) is in the proper
position for the AC supply being used.