Service manual

MDS E-SCAN MPR E-SCAN OPERATION / PROBLEM ANAYLSIS
30
3.2 Trouble Shooting Chart
SYMPTOM POSSIBLE CAUSE
No display, failsafe LED off.
No display, backlighting.
Fuse blown.
Power supply failure, check ±15vdc and
5vdc.
No display and failsafe LED on. Display failure.
Video cable failure.
Display on but is garbled. CPU failing, Display or Video cable failure
Buttons do not respond properly. Connector from overlay to I/O board not, or
improperly mated with J5.
Front panel overlay defective.
Defective I/O board (keyboard section).
E-Scan does not appear to take calibration. CPU card failure.
“NO TEMP. VOLTAGE” flashing on
display.
If voltage between TB1-3 and TB1-10 on the
IB is less than 0.2 volt and the process
temperature is above 25° C, check 2.5 volt
regulator VR-1 in the head.
Sensing head failed.
I/O card failed.
“NO MEAS. VOLTAGE” flashing on
display.
If positive voltage does not exist between
TB1-12 and TB1-3 on the IB, check for
process flow across the prism.
Sensing head failed.
I/O card failed.
Measurement incorrect. Check display for O, U, or T indicators.
Check for large digital offset value.
Re-zero using analog zero (in software).
Re-zero head using zero pot in sensing head.
“NO LAMP VOLTAGE” flashing on display. Sensing head failed.
Check for AGC voltage on LED.
Analog card failed.
I/O card failed.