Danfoss Turbocor TT Series, Service Manual

Page: 214 / 294

Figure 4-241 Backplane LED Locations - Right Side
Table 4-41 Backplane LED Locations
No. Component No. Component
1 D2: +17 VDC 6 D10: Cool-L power to solenoid
2 D1: +5VDC 7 D11: Run contact is closed when on
3 D6: + 15 VDC 8 D12: Compressor Status: Red indicates alarm or reset, Green indicates normal
4 D9: + 24 VDC 9 D13-D16: IGV Stepper Motor Indicator; flicker when operating
5 D7: Cool-H power to solenoid
4.25.2.2 Backplane Verification
NOTE
The test-point LEDs are ON if ANY voltage is present. The test points must be measured to determine the actual voltage.
1. Remove the Service Side Cover. Refer to Section 4.1.3.1 Service Side Cover Removal and Installation on
page 54.
2. With main power on, using a multimeter set for DC voltage measurements, place the multimeter leads
in the Backplane test points as defined in Figure 4-239 Backplane Test Points on page 213.Table 4-42
Backplane Test Point Values on page 215.
3. Isolate compressor power.
4. Unplug connectors J4 and J24 from the Backplane.
5. Using a multimeter set for resistance measurements, place the multimeter leads in the Backplane test
points as defined in Figure 4-239 Backplane Test Points on page 213. The results should be greater
than the resistance specified in Table 4-42 Backplane Test Point Values on page 215.
6. If one of the test points does not output the expected voltage and the HV+ and +24V test points
output the correct voltage, remove the Serial Driver, BMCC, and PWM.
7. Plug connectors J4 and J24 to the Backplane.
8. Repeat Step 2. If the voltages are as expected, the Backplane is functioning correctly and not the cause
of the energy drain.
Page 214 of 294 - M-SV-001-EN Rev. H 1/23/2023