Ericsson 19A149978P1, Maintenance Manual

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FUSE REPLACEMENT
To replace a defective fuse, perform the following pro-
cedure:
1. Place ON/OFF switch to the OFF position.
2. For fuses F1 (F1 & F4 on 978P2) or F3, remove cap
from fuse holder and replace fuse with a fuse of the
same type and rating.
3. For fuse F2, remove two screws holding fuse cover
to front panel. Remove defective fuse and replace
with a fuse having the same type and rating. Replace
fuse cover and secure using the 2 screws.
TROUBLESHOOTING PROCEDURE
Table 1 - 60 Hz Power Supply 19A149978P1
SYMPTOM PROCEDURE
No output voltage at J801 Check the following:
1. Open F1, F3 or S1.
2. AC voltage on W801.
3. Open D1, D2 or D3.
No output voltage at F801B Check the following:
1. Open F1, F2 or S1.
2. AC voltage on W801.
3. Open D1, D2 or D3.
Low output voltage on F801B or J801. Check the following:
0 < Vo < 12.5 Vdc
1. If one of the dual diodes on D1, D2 or D3 is shorted.
NOTE: All three diode packages contain two diodes each.
2. Line frequency < 60 Hz.
High output voltage on F801B or J801. Check the following:
1. Spade jumper is connected between pos 2 and 3 on
F801B. (Rev. A and earlier).
Vo . > 16.7 Vdc Plug P802 is connected to connector J802. (Rev. B and
later).
2. R1 not connected between pos 1 and 3 on F801B.
3. Line frequency > 60 Hz.
No one should be permitted to handle any portion of
the equipment that is supplied with high voltage, or to
connect any external apparatus to the units while the
units are supplied with power. KEEP AWAY FROM
LIVE CIRCUITS.
WARNING
To avoid possible electric shock, DO NOT operate
this power supply with the fuse cover removed.
WARNING
LBI-38550
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