35
Input:
NODE ( + ) MEASUREMENT SOURCE
A2U4 (IN), A2C16 (-)
≈ -24Vdc
A1U1, AlC1 ( + )
Outputs:
NODE ( + ) N0DE ( - ) MEASUREMENT
A2U4 (ADJ) A2U4 (OUT) 1.25Vdc
A2VR2 (cath.) A2VR2 (anode) 11.7Vdc
A2R33, A2R34 A2VR2 (cath.) 2.05Vdc
To check if load on -15V is shorted, remove jumper A2W3.
Refer to Down Programmer, page 39, for the + 8.9V bias supply, and refer to OVP Circuit, page 39, 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 1.0 seconds and DROPOUT goes high at 1.1 seconds after 20V (5V UNREG) reaches about 11Vdc.
DROPOUT high enables the PWM if OVERVOLTAGE, and OVERTEMPERATURE are also high.
Circuits Included. AC-Surge-&-Dropout Detector, Bias Voltage Detector, U11A, 1-Second Delay and Relay Driver--all
on A2 control board.
Setup. The Main Troubleshooting Setup, page 29. Apply the ac mains voltage to the bias transformer, and set the external
supply to 0Vdc.
Inputs:
NODE ( + ) * SETUP MEASUREMENT SOURCE
A2J3-1 wait 2s 5.0Vdc A2Q3 (emit.)
A2J3-22 20Vdc A1CR6, AlCR7
A2U20-8,10 f.w.rect.,1-2Vpk A1CR8,AlCR9
A2U22-13 TTL sq wave, 20KHz A2U22-6
Outputs:
NODE ( + ) * SETUP MEASUREMENT
A2U20-5 cycle power transition 0 to 13.5Vdc
A2U20-2 cycle power transition 0 to 1.4Vdc
A2Q6-1 cycle power transition 0 to 5.0 to 0.3Vdc
A2Q6-9 cycle power transition 0 to 0.3 to 5.0Vdc
A2U20-6 wait 2s < 0.25Vdc
A2U20-1,14 wait 2s hi (5Vdc)
A2U11-3 cycle power transition lo to hi to lo
A2U18-10 cycle power burst 1.25 KHz sq. wave 1.1s
