Filter
Top Products
45
Circuits Included.
Constant Current (CC) Circuit on A2 control board.
Setup. The Main Troubleshooting Setup, page 33, except connect the external supply with polarity reversed to the unit's +
OUT ( - ) and - OUT ( + ) terminals. Apply the ac mains voltage to the isolation transformer. Set the external supply to
3.0Adc constant current with a voltage limit in the range 5 to 20Vdc. Set mode switches B1, B2 and B3 to 0. Set IP to 0Vdc
by connecting to
P or set IP to + 5Vdc by connecting to A2J7-24 according to SETUP below.
Outputs:
NODE ( + ) NODE ( - ) SETUP MEASUREMENT
IM A2J7-4 IP = 5 (6015A) 0.125Vdc (0.88Vdc, 6015A)
A2U4-8 A2J7-4 IP = 0 -14Vdc
A2U4-8 A2J7-4 IP = 5 +14Vdc
If the failure symptoms include output current oscillation, check if the differentiator circuit is at fault by removing resistor
A2R35 ( 1M ohm) (3.3M ohm, 6011A). If oscillations stop, the differentiator is probably at fault.
Troubleshooting OVP Circuit
Flip-flop A2U8A-A2U8D is set by comparator A2U8C and reset by PCLR . TTL low at A2U18-12 inhibits the PWM.
OVP Program Voltage on A2J7-7 is equal to Eout/10.
Circuit included. OVP Circuit and 2.5V bias supply on A2 control board.
Setup. The Main Troubleshooting Setup, page 33, except connect the external supply to the unit's + OUT ( + ) and - OUT
( - ) terminals. Apply the ac mains voltage to the isolation transformer. Adjust the unit's OVP limit to 10Vdc. Set the
external supply (EXTERNAL) as instructed below.
Outputs:
NODE ( - ) = A2J7-4
NODE ( + ) SET VOLTAGE
EXTERNAL (Vdc)
SETUP MEASUREMENT
A2U7-2 - 2.5Vdc
A2J7-7 - 1.0Vdc
≈2.2Vdc (6015A)*
A2J7-13 5 hi
A2J7-13 15 lo
A2J7-13 5 lo
A2J7-13 5 cycle power hi
* Front panel OVP control turned fully cw.
Note Connecting a test probe to either input of either comparator in the OV Flip flop (pins A2U8-1, 6, 7, 10, 11
or 13) may cause the flip flop to change states and cause the probed input to be low.