Specifications
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SECTION 5 MACHINE TESTING / TROUBLESHOOTING / SERVICE
5.13 Shunt (31488)
The Feedback shunt consists of a .001Ω resistor that feeds back a 0 – 100 mV signal to the PCB control
module on P6-10 & P6-11. This voltage is input to the shunt amplier on IC4 and a positive voltage is out-
put to the error amp section of IC5 pin 9. This is compared to the reference signal entering the circuit on
Pin 6 of IC5. The negative output of this op amp, on pin 7, is sent to Pin 9 of IC5 where they are summed.
Any voltage dierence here results in an error signal being generated from pin 8 of IC 5 and sent to the
PWM chip, IC 6 on pin 2. This will increase or decrease the Duty cycle of the PC650 accordingly until the
current level is corrected.
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