BrownBear
Member
Hi, I just bought a 1997 JLG 40H that operates normally from ground controls, but the engine dies when switched to platform controls. It has spent a lot of time sitting outdoors in extreme weather so I am bracing myself for finding a variety of issues in the controls and boom wiring. The machine is in a remote location so I am trying to make sure I have all the necessary tools when I show up for an extended troubleshooting session.
It looks like that vintage of 40H uses P-Q Controls joysticks. The thing I am unclear on is whether these emit Pulse Width Modulation (PWM) signals, which would mean if I find an issue with one of those controls I'll want an oscilloscope to examine the output waveform. I have seen conflicting information in the forums about whether this generation of 40H uses PWM in some of the control lines, or some simpler all-on or all-off signaling that I can troubleshoot with just a multimeter. Does someone know for sure?
Related question: I have found PDFs of the general service and parts manuals but apparently there is technical publication supplement (JLG part number 3120351) with detailed information about adjustment and troubleshooting of the P-Q joysticks. Does anyone know if a digital version of this exists?
Thanks! - Tim
It looks like that vintage of 40H uses P-Q Controls joysticks. The thing I am unclear on is whether these emit Pulse Width Modulation (PWM) signals, which would mean if I find an issue with one of those controls I'll want an oscilloscope to examine the output waveform. I have seen conflicting information in the forums about whether this generation of 40H uses PWM in some of the control lines, or some simpler all-on or all-off signaling that I can troubleshoot with just a multimeter. Does someone know for sure?
Related question: I have found PDFs of the general service and parts manuals but apparently there is technical publication supplement (JLG part number 3120351) with detailed information about adjustment and troubleshooting of the P-Q joysticks. Does anyone know if a digital version of this exists?
Thanks! - Tim