Troubleshooting the VFD Voltage Supply
This information deals with schematic lE.
li
the display stays dark but the power supply voltages are correct,
the failure might be caused by the VFD voltage supply. Check the
following:
• U603 pin lO (LVFDEN) must be low, to enable the VFD supply.
• VDISP should be approx. 40 Volt if no Module is instal1ed.
• Check that the waveforms at U603 and T60l are as shown below.
Incorrect wave forms and levels could be caused by R60l and C602.
U603
-----+27V
U603/11
----.Qv
-----+27V
U603/14
----·N
_----+7V
T601l6
-----+3V
I
_----i-7V
T601/8
-----+3V
LTriggerA
T601
LTriggerA
f--t--t--t--t--t--t--t--t---t---!
2usIDIV
Figure 4-4. Pulses trom U603 and T601
Troubleshooting 4-7
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