B&K 1794 instruction manual Unregulated O/P Voltage

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( B ) UNREGULATED O/P VOLTAGE

UNREGULATED O/P VOLTAGE

Is IC LM324 OK ?

N

 

Y

 

Is Voltage Pot Open OR

N

Pot Wire is Reaching PCB ?

 

Y

 

Are Mosfets OK ?

N

Y

 

Is Gate Wire of Mosfet

N

Reaching PCB ?

 

Y

 

Are Diodes D3 and D4 on

N

Front Panel PCB OK ?

 

Y

 

Is INT & COM Terminal on Back Panel Short ?

N

Short INT COM Terminal when External Programming

is not in use.

Replace the IC.

Replace the Voltage Pot and Ensure proper continuity with the PCB

Replace the Damaged

Mosfet.

Ensure proper continuity of Gate Wire and PCB.

Replace the Damaged

Diode.

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.

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Contents BK Precision Limited Two Year Warranty Table of Contents Output ON/OFF Switch Limit SettingSection General Information Description Remote Programming With External 5K PotSection Specifications Section Installation Input TAP Selection for 230V Operation Repackaging for ShipmentSection Operating Instructions Readjust the current limit in the remote sensing mode Reverse Current Loading Output CapacitanceReverse Voltage Loading Terms in this Manual Terms AS Marked on Equipment Operators Safety SummaryUSE the Proper Power Cord Servicing Safety Summary For Qualified Service Personnel onlyDo not Service Alone USE Care When Servicing with Power onServicing shall be done only by Qualified personnel Section Service Instruction GeneralTrouble Shooting Techniques Repairs & Maintenance Page REF. PCB no PIN no Parts Ordering & ReplacingPage Page Fuse Blows Fault Finding ProcedureFuse Blows Unregulated O/P Voltage Unregulated O/P VoltageNo Output Voltage No O/P VoltageNo DPM Indication No DPM IndicationDPM not Read Unit not Take Current Unit not Take CurrentUnit Directly Goes to CC Unit Directly Goes To CCNo Current Control Poor Line RegulationNo Current Control Poor Line RegulationPoor Load Regulation Poor Load RegulationCV, CC, LED not Glow External Programming Not OK External Programming not OKRemote Sense not OK Section Part List & Schematics L1791-FP-CNT-0603 PCB Assy1KPF/100V, Disc 2P2W SW Push ButtonSW1 Grey Colour CAP for Push Switch SW2 SW3 PS-PREG-1791-0503 PCB AsslyDPM/01 REV 01 X PS-AUX-DC-L1791-0503 PCB Assly PS-PWR-L1791-0703A PCB AsslyBack Trough Assly Front Panel AsslyMain Chassis Assly Front Panel Layout Back Panel Layout TOP View Bottom View of Model 1790 Front Panel Control PCB of 1790 Power Module PCB of 1790 PRE Regulator / AUX. P/S PCBs 1790 Service Information Precision CorpPrecision Corp