Dc Power Supply Fuse - Printronix p300 Maintenance Manual

5–40. DC Power Supply Fuse (Figure 5–39)
NOTE: For floor cabinet (XQ) models, refer to Figure 5–22
a. Removal
High electrical potentials may be present at the power supply even with
power disconnected. Exercise care; electrical shock hazard exists. Before
handling any parts, allow at least 10 minutes after power–down for capaci-
tor C1 to bleed off any remaining voltage.
1. Disconnect power cord (1). Wait ten minutes before continuing.
2. Loosen two fasteners (2) and allow rear door (3) to swing open. On floor cabinet (XQ) models, do
the XQ steps of paragraph 5–18a.
3. Swing out card cage (4).
4. Check capacitor C1 for a 1K, 10W resistor between C1+ and chassis ground. If resistor is not
present, temporarily install a 1K, 10W resistor between C1+ and chassis ground.
5. On capacitor C3 (6), temporarily install a 1K, 10W resistor between C3+ and ground.
6. Inspect fuses F1 (7), F2 (8), and F3 (9) on power supply PCBA (10).
7. Remove and inspect secondary fuses F4 (11) and F5 (12) if present.
b. Installation
1. Replace any blown fuse with fast blow type. See below.
FUSE TYPE
F1 8AFB
F2 3AFB
F3 3AFB
NOTE: Secondary fuses are not present on all units.
F4 15AFB
F5 5AFB
2. Remove temporary bleeder resistors installed on C1 (5) and C3 (6).
3. Swing card cage (4) back into place. On floor cabinet (XQ) models, do the XQ steps of paragraph
5–18b.
4. Close rear door (3) and tighten two fasteners (2).
5. Reconnect power cord (1).
5–88
WARNING
– –
VOLTS (P600)
+36
+5
–36
P300/P600 Corrective Maintenance
VOLTS (P300)
+8
–30
+28