B&K Precision 1794 - Manual - Manual (Page 20)

( B ) UNREGULATED O/P VOLTAGE
UNREGULATED O/P VOLTAGE
Is IC LM324 OK ? Replace the IC.
Is Voltage Pot Open OR Replace the Voltage Pot and
Pot Wire is Reaching PCB ? Ensure proper continuity
with the PCB
Are Mosfets OK ? Replace the Damaged
Mosfet.
Is Gate Wire of Mosfet Ensure proper continuity of
Reaching PCB ? Gate Wire and PCB.
Are Diodes D3 and D4 on Replace the Damaged
Front Panel PCB OK ? Diode.
Is INT & COM Terminal on Back Panel Short ?
Short INT COM Terminal when
External Programming
is not in use.
1. Check IC LM324 on Front Panel PCB (L1791-FP-CNT0603).
It might be damaged.
2. Check Voltage Potentiometer (5K Pot), whether it is open or whether the
wires associated with Voltage Potentiometer is reaching the Front Panel PCB.
3. Check the Mosfets and Zener Diodes across Mosfet.
It might be Short.
4. Check Diodes D3 and D4 on Front Panel PCB.
It might be Leaky or Short.
5. Ensure proper continuity of Gate Wire on Front Panel PCB and Mosfet module.
6. Ensure INT and COM Terminal at Back Panel are short when External
Programming is not in use.
Y
N
Y
Y
Y
Y
N
N
N
N
N
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