HP (Hewlett-Packard) 6269b Computer Accessories User Manual


 
TM 11-6625-2958-14&P
be set much closer to the operating
output voltage of the supply.
5-109 MAXIMUM CROWBAR TRIP VOLTAGE
5-110 To adjust the maximum voltage at which the
crowbar trips, proceed as follows:
a. Rotate A5R125 (OVERVOLTAGE ADJUST)
and CURRENT controls fully clockwise.
b. Disconnect either end of R72 (TP70 or
TP71; see Figure 7-10).
c. Connect decade resistance box in place
of R95 (mounted on standoffs on main circuit
board).
d. Turn on supply and adjust VOLTAGE con-
trols for output voltage shown below:
Model
Value
6259B 12Vdc
6260B
12Vdc
Model
Value
6261B 23Vdc
6268B
45Vdc
6269B
45Vdc
e.
Adjust decade resistance box until crow-
bar trips (amber OVERVOLTAGE lamp lights up).
f.
Replace decade resistance with appro-
priate value resistor in R95 position and reconnect
resistor R72. Maximum crowbar trip voltage is
now set at voltage given in Step (d).
5-111 CROWBAR DISABLEMENT
5-112 To disable the crowbar completely, discon-
nect either end of R98 (TP97 or TP98). This resis-
tor is mounted on the main circuit board (see Fig-
ure 7-10).
5-22