40
Input:
NODE ( + ) NODE ( - ) MEASUREMENT SOURCE
A2C55(+) A2C55(-) ≈ 27Vdc A1U4, AlC16 ( - )
A1U4, AlC18 ( - ) (6011A)
Outputs:
NODE ( + ) N0DE ( - ) MEASUREMENT
A2J7-21 A2U12-3 (ADJ) -1.25Vdc
A2J7-21 A2VR4 (Anode) -12.9Vdc
A2C54 ( + ) A2C54 ( - ) 13.8Vdc
To check if load on -15V is shorted, remove jumper A2W3.
Refer to Down Programmer, page 42, for the + 10.6V bias supply, and refer to OVP Circuit, page 45, for the +2.5V bias
supply.
Power Section Blocks
This section contains the blocks referenced in Tables 3-2 and 3-5.
Troubleshooting AC-Turn-on Circuits
Relay A1K1 closes at 2.5 seconds and DROPOUT goes high at 2.9 seconds after 20V (5V UNREG) reaches about 13Vdc.
DROPOUT high enables the PWM if OVERVOLTAGE, and OVERTEMPERATURE are also high.
Circuits Included. AC-Surge-&-Dropout Detector, Bias Voltage Detector, Delay Circuits, and Relay Driver--all on A2
control board.
Setup. The Main Troubleshooting Setup, page 33. Apply the ac mains voltage to the isolation transformer, and set the
external supply to 0Vdc.
Inputs:
NODE ( + ) * SETUP MEASUREMENT SOURCE
A2J7-24 5.0Vdc A2Q9 (emit.)
A2J7-22 ≈ 21Vdc A1CR2,AlCR5
A2U11-16 f.w.rect.,0.8Vpk A1CR3,AlCR4
A2U20-13 TTL sq wave,20KHz A2U20-6
Outputs:
NODE ( + ) * SETUP MEASUREMENT
A2U17-9 cycle power ≈ 13.5Vdc
A2U17-14 cycle power ≈ 1.4Vdc
A2Q11-14 cycle power transition 0 to 5Vdc at 2.5 sec
A2Q11-4 hi (5Vdc)
A2U9-10 cycle power 2.9 s burst 1.25KHz sq. wave
A2U9-15 cycle power one 840ms pulse then hi at 2.5 sec
A2U9-14 cycle power three 420ms pulses then hi at 2.9 sec
A2U9-1 cycle power transition lo to hi at 1.7 sec