Cadac F-Type - Manual (Page 100)

APP-IV
F-Type Revision F2005-2
2. Turn on the PSU and press the START button.
3. Put probe on the 13V O/P cap and adjust the O/P adjuster on the 13V block until
the meter reads 13.00V ±0.05V.
4. Move the probe either to TP1 and TP2 (0V) on the front panel mounted control
card 8023, or to PIN 8 and PIN 3 (0V) on the ‘D’-connector on the front panel.
Adjust the front panel mounted “offset adjust” pot (see figure 1-19) as close to
0.00V as possible.
5. Connect a load to the 48V O/P pins capable of drawing a current of 600mA.
6. Locate the 5568 BOARD, There is only one 5568 board used in the 48V PSU,
and this is mounted near the middle of the left hand side.
7. Connect a digital volt-meter between the -V and +V terminals of the output
capacitor.
8. On the 48V regulator card 5813, increase the output by turning the “O/P Voltage
Adjust” potentiometer, until the volt-meter reads 50V. Note that when the PSU
“trips”, the power switch must be turned off immediately. Turn the “O/P
Voltage Adjust” potentiometer on the 48V regulator card ‘down’ a few
turns, before you try again.
a) If the PSU “trips” at 50V (±0.5V), the 5568 is set correctly and no further cal-
ibration of the 5568 card is required.
b) If the PSU “trips” before you get to 50V, the 5568 card is set too low.
c)
If the PSU does not “trip” when you measure 50V, the 5568 is set too high.
Re-calibrating the 5568 Over-voltage Protection board
9. 5568 set too low.
i) Adjust the potentiometer on the 5568 card by a few turns clockwise.
ii) Increase the “O/P voltage adjust” potentiometer on the 48V regulator, until
there is 50V across the O/P capacitors.
iii) If the PSU “trips” before 50V is reached, repeat sub-procedures (i) to (iii).
iv) When the voltage across the O/P capacitors stays at 50V, very slowly turn
the potentiometer on the 5568 card ‘anti-clockwise’ until the PSU “trips”. The
card is now calibrated.
10. 5568 card set too high.
i) Check that you measure 50V across the O/P capacitor. If not, adjust the “O/
P Voltage Adjust” on the 48V regulator card until you get 50V across the O/P
capacitors.
ii) Very slowly turn the potentiometer on the 5568 card ‘anti-clockwise’ until the
PSU “trips”. The card is now calibrated.
11. With the power OFF, turn the “O/P Voltage Adjust” potentiometer on the 48V reg-
ulator card ‘anti-clockwise’, by a few turns so that the 5568 card does not “trip”
the PSU when the power is turned ON.
12. Turn on the power and reset the “O/P Voltage Adjust” potentiometer on the 48V
regulator card so that you measure exactly 48V across the O/P capacitor.
Fault-finding tests
13. Check the green LEDs (Mains OK and O/P OK) on the power blocks. These
LEDs should light when the push to start button is pressed.
14. If either of the red LEDs “over-voltage” or “current limit” are illuminated, return
the power block for replacement (NOTE: DO NOT attempt to service the blocks.
Lethal DC-voltages are exposed underneath the cover.)
15. If MAINS OK LED does not come on, check the fuse. The fuse should only be
replaced with a 10A HBC TYPE T fuse.