Supply Board - AEMC 5600 Repair And Calibration Manual

MODEL 5600

SUPPLY BOARD

1) Operating:
a) Protections against overloads 110/220V
In case of error 100-200V, voltage at transformer secondary is exceeding zeners
conduction level, it triggers Q301 that closes itself. Secondary being short-
circuited, current in primary increases quickly, CTP RT301 overheats until it
opens itself, disconnecting main supply primary at the same time.
Processing delay: approx. 2 sec.
Wait until CTP is cold before using charger again.
b) Load
Once rectified and filtered, load current goes in battery through regulator Z301.
Current limit is defined by both Q302 and R303 to R306. (I = Vbe = 0.8A)
CR306 limits voltage +Batt in case of loading attempt with no battery. V limit = 9V.
CR304 keeps regulation steady even in case of disconnection to CR26 (signal
changes).
2) TROUBLESHOOTING:
• First check programming of main supply voltage (S301). In case of bad
programming, wait until CTP RT301 gets colder.
• Even if programming of voltage is right and CTP opens each time the instrument is
plugged in, check Q301 that may be short-circuited, or CR301 diodes or level is
not right (BZX 55 C 20V).
• If there is no more load current, make sure that the battery is working. If
necessary, replace the battery by a resistor (7.5Ω/5W) and check if charger is
operating.
• Make sure that CR304 is not disconnected.
• Check VR308 = 1.25V ± 0.05V. If not, change Z301.
• Load current value is: Ich = Vbe (Q302)
HEAT SINK PLATE
1) Operating:
a) Principle
When overload occurs, once zeners conduction level is exceeded, triac transistor
is triggered and then puts itself into short-circuit, this way helping F1 or F2 fuse to
melt.
10/27/99
REPAIR & CALIBRATION MANUAL
Req 303 to 306
16
REVISION 7: June 11, 1999
FILE LOCATION: E.F. Disk - Manuals - Cal. Man. - Model 5600.DOC
That is to say = 0.8A
CAT# 1431.01
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