Filter
Top Products
Service Addendum16
OV at Turn-On Troubleshooting
Figure 3-7. OV at Turn-on Troubleshooting
"OV at Turn-On"
Start
Check that the supply is not programmed to OV at
turn-on. Ensure that the voltage setting is not greater
than the OV setting. Program 0V and Max. OV, then
save the settings in Register 0 (press shift, save, 0
and Enter key). Turn the supply off then back on.
Connect a DC coupled scope across the output
terminals. Turn the supply on and check that the
output does not momentarily go higher than the
voltage setting.
Momentarily goes high
?
Yes
OV still ocurrs
?
Output high
?
Yes
Check voltages at A1U405-7 (TP44), U603-5 (TP17,
U405-5 (TP42) and U405-3 (TP41) to Common
(TP9). See Table 6-3.
A1U405-7 approx 5V
?
Check A1U411.
Replace A5 DSP board
Caution: During
these tests, the
output may be at
hazardous levels.
Turn off the supply and remove the top cover.
Disable the OV circuit by lifting A1R447. Turn on
the supply and check the output voltage.
Yes
Go to "Output Held High"
Troubleshooting
Check A1R447,
R446, C417
Yes
Yes
A1U405-7 approx 5V
?
A1U405-7 approx 5V
?
Check A1U405.
Check A1R644,
C417.
Yes
Yes
Yes
No
No
No