couldn't find a particular area for boom lifts and thought could use some collective knowledge, have a JLG 450 aj series 2, machine has been a pain but getting it back working, had recently had to pull basket to get some cylinders resealed, got back together and worked great, went out for a rental (joys of rental fleet) and came back with a intermittent issue with the platform tilt, rotate and jib, boss unloaded and couldn't get those 3 controls to work from the basket, by the time he passed on to me I can always get the basket side to work but I cannot get the same controls to work from the ground controls. brought into our small shop to get out of the snow and tried this morning and got the controls to work from the ground controls briefly then stop and can't get them to work again. everything is still working from the platform. controls still giving some signal as unit will ramp up from hitting the controls so load sense seems to be working but getting no movement. JLG manuals and tech support are all about their analyzer which as we only have the one unit boss doesn't really want to buy if don't need to, still digging into the machine but thought someone out there may have an idea or come across something similar
My first thought is bad wiring somewhere.
thats about what I am at but trying to trace it down is proving interesting, seems to be a canbus set up (JLG is not helpful ie here is a link to buy a analyzer) but if the canbus wiring was broken should have an issue either way, not only loose a few functions on one operation station, a control board maybe but that's an expensive option and don't want to just load a parts cannon
For any communication problems scanner is a fastest thing. ( You can find JLG scanner pretty inexpensive). If you suspect communication problems, first thing with CAN BUS is check the network impeadance ( I know it is DC circuit, but that’s what network people call it). It should be around 60 OHM. If it is 120 Ohm - you lost one of the resistors. But usually it will cause weird operation, and not intermittent shutdown. With intermittent lost of functions or control from one of the stations on network controlled machines, if lift dies altogether, it means main feed, main feed return or emergency button switch problems. If rest of the machine is functioning, but you loose all the controls from platform - it’s just an intermittent loss of continuity of network wiring. But first and foremost - I would check loss of the ground to a platform. Suggest doing it under load. If you loosing a communication with a few network controllers, the system will operate rest of them with no problems. To check the CAN BUS signal you would need two channel scope, or go off of the scanner data.