I seem to have one of my PQ controllers (the main lift control) on my jlg 50ht going bad on me. sometimes it doesn't work at all and other times it works flawlessly. if it makes any difference I think at this point it might be related to outdoor temperature since it seems to be working fine when it's warmer and not working when it's cold....havn't tested that a lot yet though. all other functions work fine. my current work around is to get the lift in place then swap the harnesses between the drive and lift controls and use the drive control to lift the boom. I tried replacing the potentiometer just to see if that made any difference (something I could do easily enough) and it didn't change anything. I had looked up the price of a replacement controller and about had a heart attack but also saw I could have one rebuilt for around $360....still pretty expensive. I was wondering if anyone out there had a cheeper alternative than this, or if someone had some pointers on how I could rebuild it myself? I tend to be pretty good with taking things appart and fixing them as long as I know what I have to replace/fix while I'm in there. I had looked into taking it appart before but couldn't quite figure out how it was supposed to come appart. didn't want to break it then be forced into buying a new one. any ideas? thanks, Mike
I have replaced several of these. I dont bother to even try and fix them. I just buy remanufactured ones. Try Equipment parts wholesale or Hendley electronics in Bowling Green Ohio. I believe they are about $175 with core charge
Same here barklee, I just get re-man PQ cards from Hindley Electronics. As long as the body, lever, and lever lock is still in good shape, all you need is replacement circuit card with pot.
Ya atco, seems like everyone we have had go bad will stop all the sudden and you can adjust the pots back to working order but they never have that proportional ability to them. I tried to rebuild one with old parts and it was never right, but got through the job. Do you specialize in man lifts? I have read several of your posts, seems like youve been around them a time or two. Ever have a wheel just lock up on a 600s? Just one wheel very strange. I removed the hub and didnt see any metal or dirt, all the gears looked ok. Got me stumped
http://www.ctech-ind.com/Default.aspx Just type in the JLG part number. Bobby
Yep, they either loose their proportional ability or crap out alltogether, time for a new circuit card. Haven't worked on many 600S machines. Will the machine still drive with one wheel locked? Could have blown seals on brake piston, won't release that brake. Try disconnecting the hub on locked wheel, then disconnect brake hose from brake assy. Fit a plug in disconnected brake hose. See if machine will drive. You may still have problem with that motor trying to turn with brake engaged affecting other motors. If so, remove motor from brake. Motor will now spin free, but transmission valve (flow divider) should apply oil to other motors and make machine drive. Try this out, I'm curious about the results.
We pulled the drive motor and wired it up out of the way and ran the machine around for maybe 5 minutes. Seemed like it was a little hot but not really out of hand.
Wait a minute, what was a little hot? The motor, or the brake? Did you disconnect and plug the brake line to that motor as well?
Didnt remove the brake just the motor. It spun freely as it should. The motor was to the touch maybe a little hotter than the others. Is there a brake on each wheel?
Hmm, trying to noodle through what you've described. You said you had one wheel lock up, I figure that meant the machine wouldn't move. You took the planetary hub apart on suspect wheel and found no issues. Then you unbolted the drive motor on that wheel, pulled shaft free, and tied motor back, and did not disconnect brake hose. Machine would now drive, being driven by opposite side motor, and suspect wheel motor had shaft turning while you were driving. That pretty much sum it up? Each drive wheel would consist of three components. 1) the planetary hub, which bolts to the machine axle frame, wheel bolts to hub. 2) the brake assy, which bolts to the backside of planetary hub assy on inside of axle frame, then 3) drive motor, which bolts to the brake assy. If you were able to drive it with motor pulled back and brake hose connected, I think that tells us your brake and planetary hub is working ok. You said the suspect motor got a little warm, not necessarily burning hot. Was the oil in the hyd system this warm, or is the heat isolated more to the suspect motor? You can view the parts manual for your machine at the JLG website: http://www.jlg.com/en-US/Home.html Click "Services" in the left column of home page, then click "Parts and Service Manuals" below the "Services" tab. Then just click the links that apply to your machine, JLG...JLG Boom Lifts...600 S SJ.
Ya that sums it up. We put the hub and motor back together and ill be damned if it doesnt work fine. I dont know if there was a piece of crap inside the hub that was caught? It was strange because the wheel would hang up in the same place (one full revolution of the tire). Motor was just a little hotter than the others, system was warm. I dont recall seeing the brake on this wheel, it is four wheel drive and this was on the non trurning wheels. Would it look the same as the swing brake? I have replaced one of these.
Just that tidbit of info indicates you may have a motor problem. Find the case drain line on that motor. Disconnect it, plug the hose fitting, leave the case drain fitting on motor open, and drive machine. A normal motor would have maybe a small amount of oil coming out of that case drain fitting. If you have a fair stream of oil coming out of that fitting, you probably have a failing motor. BTW, it helps if you have an additional hose that you can connect to case drain fittting and run hose into a bucket while testing. Less messy. Yes, there is a brake assy on that wheel. It may be similar to the swing brake assy. Go ahead and find you parts manual at the JLG website and download/save it to your computer. Your going to find it handy to have for your machine.
Ok I will do that. Its back at the shop now. Never noticed the parts manuals on JLG website, thats going to be very helpfull. Thank you If you want to keep testing your skills i also have a Snorkel pro 126 that the axles wont extend on. They go out about 2" and stop. Also it seems like the throttle wont go high enough.
Follow the instructions I posted at post #10 for finding your manual at JLG site. The parts manual has your hyd and elec diagrams as well. PRO126! Your killing me! We have one that was doing the same thing. Been sitting on yard for couple months and can't raise that long boom out of way because axle won't extend. A couple weeks ago, I determined I was going to check it out and find what the problem is with axle. The damn thing shot axle out like there was never a problem. :beatsme Stupid machine! :Banghead Can't remember what kind of throttle control the PRO126 used, but if it throttles up even a little, just not enough, probably just an adjustment problem. Have you had any problems with the EMS system and have to calibrate it?
I am guessing the EMS needs calibrated. It will kick on once in a while when you know it shouldnt. You have to turn the lift off and restart it couple of minutes later. No experience doing it. You?
Calibration might help it. The EMS on those machines is quirky. Way more quirky than the systems used on 110 and 120 JLG. The calibration procedure isn't really as complicated as it looks on many pages of paper. I worked on one that had issues with the EMS a couple months ago, I got to where I could practically go through the whole process without looking at paper. You need the calibration harness for the control valves to do the whole procedure. I got one from Snorkel, can't remember what it cost, maybe 50 - 70 bucks, just can't remember for sure. They also have test harness's for the length and angle sensors, I didn't buy them. I may have the procedure on my computer at work, I'll have to look. You can contact Snorkel USA and get info directly from them. The guy who knows most about the PRO126 is Gary Wampler, hard fellow to get a hold of though, busy guy.
Thanks, i will do that.
what all machines do you guys have?
2 38 ton altec boom trucks, pro 126, terex tb110 (this is a sweetheart, even though terex sucks) 86hx, 4 genie s60, 2 600s, 1 snorkel tb60, 1 genie s65, terex tb60, terex tb44, jlg400s, jlg 460j, genie s45, genie s40, two genie scissors, 25mrt scissor, 2 lull 1044c, terex ss1048, mustang 1155, cat 246c, case 420, cat 246b, bobcat 334, takeuchi tb180, 2 roll off trucks, pete semi, two lowboys, 3 bucket trucks, two dumps. Thats why i cant get enough of this site.
That's a nice fleet of stuff! You mean 80HX+6? Those are tough machines. Never worked on an Altec boom truck. Worked on plenty of Altec digger derricks and bucket trucks. Your small Terex TB lifts, are they the models that require the "optimizer" to adjust controllers? We have a TB42 that the swing needs adjusting. I found out you need that 800 some dollar optimizer to make adjustments. Man...that BS!
thanks, We have that optimizer what a pain in the @ss. We bought the tb44 new and it was still plugged into the port! The 110 uses this as well. Alexander equipment in Chicago has them. Have you had to get parts for these machines lately. They are getting to be a expensive as Grove lifts. Plus nobody at Genie wants to deal with you on the terex lifts. We replaced the boom cable in the 110 footer (bird nested inside the boom and trashed the cable) ended up getting it from Cetex because Genie couldnt even find the part we wanted.
also, Genie cant find the hub seals in there system (i have the part numbers!) so i dont know what to do about that short of going to bearing dist. and matching them all up
Yeah, Genie is getting a little goofy since they merged with Terex. All the Genie guys I used to deal with have moved on. The guy who knew the most about the Terex unit, name was Marty something, has since retired. I like Genie units, their wiring and schematics are top notch, but they are getting a little strange to work with. JLG sucks in that you can't deal directly with the factory anymore, but JLG supports their machines really well. If you have a good dealer to work with, it's far easier to work with a JLG machine than a Genie seems like nowdays. I called an outfit called aerial service and parts in Shippensburg PA for years about aerial parts. They're not far from JLG factory. They have since been bought out by Best Line Equipment in PA, but I still deal with same parts folks, Eric and Jeremy. They are really good to work with. Bummer is, Eric is nearing retirement age. Uggg!
Marty Visser.... he is freakin terex genious. You work at a dealer or are you a dealer? I had a aerial mechanic friend that was working on all my stuff and he was fired for it! I felt really bad and still do. Ruined the friendship, but now i have been dealing with United rental in Cincinnati and they are very good. Found a mechanic im comfortable with on his billing hours and there rates are a bit better if you are a repeat customer. My skill level is a parts changer with a very little bit of trouble shooting ability. I just found that i wasted so much time trying to figure out whats wrong with this junk and not always getting anywhere. Seems to work out better if i cant figure out whats wrong right away or if i know whats wrong and dont think i can do it. I really enjoy working on equipment (better than working on the jobs) but its tough when you have downtime and need the stuff working now.
Yep, that's him. Last I heard, he has retired and no longer with Genie/Terex. :Banghead Sounds like you are working on a good relationship with United Rental. If they have some good aerial mechanics, keep using them, and pay your bills promplty. If you do this, as time goes by, you'll be put at the top of the list when you ring their phone, sort of a preferred customer. As for simple stuff, the more you work on your machines, the more familiar you get with them, learn their quirks and traits. For the hard stuff or repairs needed in a hurry, call United. I have been working on aerials for different companies since the mid 80's. Haven't worked on every model out there, but enough of them to know how they work. Went through the JLG factory, that was a blast! Anytime you have a problem with one, start a thread about it. There's a handfull of us here that have experience with aerial lifts, might be able to help you out. Aside from all this, sure with I could get back to Cincinnati, I'd love to have some ribs from Walts Hitchin Post.
Willie I seen your front Tennessee was wondering if you know of any boomlift mechanic in tn