JLG 60HA Boom Problem

[Rick Rowlands]

I'm using a friend's 60HA for a couple of weeks. It has developed a problem where the boom doesn't always want to lower. Sometimes I need to either jump up and down in the basket or quickly raise the boom then put the PQ controller in the down position for it to start to descend. Its a real pain and I am afraid that whatever isn't working is going to stop responding to the "jumping jacks" treatment one day and leave me high and dry.

The problem seems to me to be related to a solenoid valve, and the jolts caused by jumping in the basket may be enough to get a valve to fully open or close. Problem is I don't know what valve it might be or even if that is the problem. Any ideas?

BTW it works fine from the ground, and all of the other functions work great. Just the boom lowering function has the problem.

[ATCOEQUIP]

LoL...yep, I'd say you better get that fixed before someone takes a pic of you doing jumping jacks in the basket of a 60HA and posting them on Heavy Equipment Forums. :D

It's unlikely to be the coils on the hyd control valve since it works fine from lower controls. It can, however, be a problem with your PQ controller or wiring going down boom is not applying proper voltage to the coil to make it operate. Open the upper control box and see if you have plug connections for the wires coming from controllers. If so, unplug your boom lift controller and switch with a different controller, telescope, swing, doesn't matter. Now use that controller to see if the boom up/dwn works properly. Try that first.

[Rick Rowlands]

Already tried that and it didn't change anything. The wiring harness is a real mess between the basket and the cable trough on the boom with lots of butt splices and such. It makes sense that with so many splices there would be additional resistance in the circuit dropping the voltage. The owner is planning to replace that section of cabling when it gets back to the shop.

http://inlinethumb15.webshots.com/44686/2146505370033749120S600x600Q85.jpg (http://good-times.webshots.com/photo/2146505370033749120JhNIQu)
Here is a picture of the JLG lift and the building that it and the mighty Insley K12 is constructing. Actually we've made the last lift with the Insley, it has accomplished what I bought it to do. The big green thing is a 260 ton stationary steam engine, the Tod Engine.

[ATCOEQUIP]

Ok, then there's one thing we can try to check if it's the cable going down boom. JLG usually has extra wires not being used, but what I'm seeing on the schematic is that they use all the wires on the 16/30 cable on the 60HA. If that's the case, let's switch two wires. You stated it doesn't have a problem with boom up, only boom down. Open your upper control box, switch the yellow/orange wire at terminal #25 of the terminal strip with the brown/orange wire at terminal #26. Then open your lower control box and switch the same two wires on 25 and 26 of the terminal strip. Now, the wire that was operating boom up flawlessly will be operating boom down. If the boom cable is the problem, it should now cause problems with boom up. Which is not as bad as not being able to come down.

[Rick Rowlands]

OK I'll give that a try. Thanks.

[ATCOEQUIP]

OK I'll give that a try. Thanks.

Hey, I hope that does the trick. Otherwise, things get more complicated. ;)