ESAB LTR 160, Service Manual

Page: 15 / 46

-- 15 --
cltr0de2
LTR 160/200, new HF generator and recifier unit
New HF generator from ser. no. xxx--006--xxxx. See the description on page 18.
New design of the rectifier unit from ser. no. 011--xxx--xxxx. See C10, L04 and L05 in the
component description and items 430 and 530 in the spare parts list.
DESCRIPTION OF OPERATION CIRCUIT BOARD AP01
This description refers to the wiring diagrams and to the components layout diagrams.
Only those items that are connected to the inputs and outputs of the circuit board are
described here.
If there is a fault on the circuit board, the whole circuit board must be replaced.
After replacing the board, the machine must be soft--started, as described on page 33.
1 +30 V +20 V
±
10 V Power supply
+30 V
Power supply to the gas and HF relays.
±
10 V
Voltage tolerance
±
5%. The power supply from transformer TC01 is protected by
two 1.25 A slow--blow fuses.
+20 V
Power supply to the control amplifier, the pulse width modulator and the gate
circuits.
Voltage tolerance
±
5%. The power supply from transformer TC01 is protected by an
800 mA slow--blow fuse.
Capacitor C93 slows the rise time of the 20 V supply at power--on, which delays the
gate pulses to the MOSFET transistors.
HL01 is an indicating lamp on the front of the machine, lighting to indicate that the
main power switch is On.