# Scissor Lift Troubleshooting



## derit

Welcome to the forum!


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## dmxtothemax

Put a DC volt meter on the batteries
What happens to the DC voltage
When you engage the hydralics ?
How far does it drop ?


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## lford250

dmxtothemax, I haven't put a meter on the batteries yet. I will try to do that tomorrow. I had the charger plugged up yesterday and according to the gauge on the charger, the batteries seemed to be charged up fine. But, I will double check them with a meter. It has done this in the past, but seemed to just go back to working on its own. I'm not sure if a relay is coming and going or not. Thanks for your advice.


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## backstay

trouble shooting is not hard. If the hyd won't run, what makes it run? Is it a solenoid? What's the voltage at the solenoid, what should it be? Keep working backwards from there.


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## lford250

backstay thanks for your reply. It appears that the solenoid is clicking, but the motor is not running. How would I know what the voltage should be at the solenoid since I don't have any paperwork on this thing? Thanks again.


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## sparkywannabee

You have a bad motor. Is it a JLG. what model and year.


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## lford250

sparkywannabee, I'm not sure what brand or model that it is. I bought it used a long time ago and have never known what the brand or model is. It was painted yellow when I bought it, but I'm not sure if that was the original color or not. I bought it from an equipment rental place. If it does turn out to be a bad motor, do you have any idea how much a new motor would cost? Thanks.


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## sbrn33

There is a nameplate somewhere. Find it.


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## telsa

The usual clicking is the solenoid// relay cycling in and out of contact.

The batteries are the problem.

You screwed up.

Never let your lead-acid batteries go that long without being recharged.

They will ALWAYS internally discharge. 

This is inherent to wet cell batteries -- in particular.

To top that off, scissor lifts ALWAYS have conducting solutions coating all over the battery tops. 

You need more than a bare bones charger to bring them back up.

There are a lot of videos on battery 'games' on YouTube. Take a peak.

Your terminal posts are also in a serious need of PM. 

Pull all cables -- clean -- re-secure. You're dealing with lead -- not copper.

&&&

Failure mode #2. You've got a dead spot on the armature of your DC pump-motor.

Failure mode #3. You've worn through your DC to commutator brushes. Yes, they wear out. 

I'll bet that you've never, ever touched them.

That also goes for the prior owner.

So now they make feeble contact. The lift gets 'twitchy.'

Solution: keep the motor -- replace the brushes. They cost peanuts and for such a motor are easy to swap in the field.

&&&

A robust -- high end -- battery charger can be used in "motor starting mode." Yes, these are the roll-around chargers you've seen at service stations across the nation.

You can hook that puppy up and then crank the lift -- just up and down, please.

This step eliminates the batteries as an issue. ( Leave them hooked up )

For ANYONE with a scissor lift -- get such a charger -- and never leave it at the job.

Such chargers make it possible to entirely recharge your scissor lift -- during the work day -- during lunch and breaks.

So, you're NOT dependent upon having your critical machine getting a charge over night. 
( When your machine gets unplugged so that the other guy's lift gets a charge. )

Such chargers can be 'buddied up' -- if you know how to wire DC circuits -- so that you have either 24 VDC or paralleled 12 VDC charging systems. 

If you tinker around, you can convert a 12 VDC charger into a 24 VDC charger. 

Yes, play with a transformer swap out // re-wire a center-tapped transformer.

:thumbsup: 

Do relabel such a modified charger. ( I'd go with a two position relay, myself. )

I leave the details up to you. :whistling2:


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## Rns

Just went through this in the summer on an old lift. Had the same issues of just a solenoid clicking. Instead of scraping it after failed attempts with some new parts, it was decided to spend a little more money. Called the service tech and he came out. It was a pleasure watching him tighten the battery cables another turn and a half. Fixed! 

The tech said these lifts are super sensitive to voltage and to keep the cables cranked down.


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## lford250

Thanks Telsa and Rns. I really do appreciate all of your information. I am going to check the cable connections and the voltage on the batteries tomorrow and hopefully find out what I need to do from there. Telsa, if its determined that I need to get the batteries charged back up properly, do you know where I could take the batteries to have them recharged since I don't have one of those super chargers that you are talking about? Thanks again.


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## sbrn33

Is there not an onboard charger? most lifts are 24 volt and use 4-6 volt golf cart batts. If you don't have one go to ebay and get one. You need to charge batts and check water at least once a week wether you use it or not.


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## lford250

sbrn33, thanks for the information. My scissor lift is set up just like what you are talking about. It does have the onboard charger for the four 6 volt batteries. I just thought that Telsa meant that I needed a super charger to get the batteries back up to where they need to be, since I haven't kept them charged up in a while.


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## sparkywannabee

lford250 said:


> sparkywannabee, I'm not sure what brand or model that it is. I bought it used a long time ago and have never known what the brand or model is. It was painted yellow when I bought it, but I'm not sure if that was the original color or not. I bought it from an equipment rental place. If it does turn out to be a bad motor, do you have any idea how much a new motor would cost? Thanks.


You said it has stopped working intermittently for a while, this tells me you have a bad spot in the motor. Not a good idea to let any batteries go dead for extended period of time. You check them with a battery tester, put some load on it. JLG, and I am sure Genie as well, have excellent manuals online. They had different motors they used, Ohio, Leeson etc, you will have to get a number of the motor and prolly find a new one, surplus, on Ebay for under $500. I would just get a new motor.Keep the pump. There will be a plate on the lift, the serial# is critical when you look up schematics online. Also, bad idea to keep it outside if you can avoid it, Georgia winters not as bad as Ohio, but the elements are hard on hoses and such.


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## sbrn33

lford250 said:


> sbrn33, thanks for the information. My scissor lift is set up just like what you are talking about. It does have the onboard charger for the four 6 volt batteries. I just thought that Telsa meant that I needed a super charger to get the batteries back up to where they need to be, since I haven't kept them charged up in a while.


No you don't need that. Plug it in and check the voltage. It should be around 28 volts or so when charging. Water is a big deal. 
It is probably not the charger or batts but you never no and it is easy to eliminate them as a problem. It doesn't hurt to redo all those connections.


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## A Little Short

lford250 said:


> Thanks Telsa and Rns. I really do appreciate all of your information. I am going to check the cable connections and the voltage on the batteries tomorrow and hopefully find out what I need to do from there. Telsa, if its determined that I need to get the batteries charged back up properly, do you know where I could take the batteries to have them recharged since I don't have one of those super chargers that you are talking about? Thanks again.


The lift should have a charger on it.
Unless your batteries are bottomed out you shouldn't need any "super" charger.


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## lford250

sparkywannabee, thank you. When you say that it has a bad spot on the motor, what exactly does that mean? Do you mean it has a short in the windings? Or, do you mean that the brushes need to be replaced?


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## lford250

sbrn33 and A Little Short, thank you. I will load test the batteries tomorrow and see what kind of voltage that I'm getting. I will also check all of the battery connections to make sure that there is not corrosion build up somewhere and then tighten them down good.


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## sparkywannabee

lford250 said:


> sparkywannabee, thank you. When you say that it has a bad spot on the motor, what exactly does that mean? Do you mean it has a short in the windings? Or, do you mean that the brushes need to be replaced?


More likely bad insulation, scissor lift motors don't get a lot of actual run time, rental places don't hang on to them too long, brushes last forever. I have worked on big DC motors that ran 24/7 and did'nt have to change brushes for 10 years.


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## lford250

sparkywannabee, thank you. I appreciate it. I will get it checked out. I've never changed the brushes, but the lift has not had much activity in a good long while. So, maybe it is the insulation in the motor.


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## sparkywannabee

BTW, it could very well be a 48V system, they are most common. Check the main fuse right by the contactor, if its totally quit working now it might be blown, which would also indicate bad motor. I think its the motor cause I had the exact same thing happen on a 40' boom. When I come across old, wore out stuff, i usually just replace it. Helps I have a credit card with a $15000 monthly limit, I am the only maint. guy and don't have a lot of time to waste trying to nickel and dime.


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## lford250

sparkywannabee, thank you. I will check the fuse if I can find it. I'm pretty sure that I have a 24 volt system, but I will double check that tomorrow also. I wish I had that same credit card that you have. lol


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## telsa

The, so-called, super duper chargers are imported these days from China.

A small one cost me $45, IIRC... just killer expensive, when you think about it.

You want one that's beefier - that rolls - the last one I bought for my boss cost $190 -- thirty-years ago. ( made in America back then )

The typical 12VDC battery charger uses a center-tapped transformer, and in the bigger sizes simply uses paralleled full wave diode bridges. 

These exotic beauties go for about $8 a pop at Fry's. Heh.

The PRIMARY reason to get the big charger is because it will have a high output setting that permits:

1) Instantly replaces the batteries for testing purposes. 

This is a huge labor saver. Instead of ^&&% around with the batteries -- just figure out which is 'sick' - the system or the cells.

2) Such chargers can take a battery up from dead flat. 

Your on-board battery charger is not designed to do that. 

It's a bare bones full wave rectifying circuit. 

My DeWalt 'exotic' can de-sulfinate a battery. It has the electronic logic to do that.

No lift ever made has that trick circuit. The manufacturers are in the lift biz not the battery-charging biz.

3) But, more important than the above, It stops you from stopping work... because your lift will need a full night's charge -- or a total battery swap. ( Is IF. )

The rolling units can toss 80 amps at 24 VDC. ( don't hold me to that -- just a ball park.

[ If you sent line voltage through the diode bridges they'd crank out 80 amps at 108 VDC... if the conductors were big enough. It's the amps, not the volts that limits them. -- and heat dissipation, too. I've got bridges rated up to 600 VDC. ]

As for sources.

http://www.northerntool.com/shop/to...eries-chargers-jump-starters+battery-chargers


 Schumacher Wheeled Starter/Charger — 200/100/40/10/2 Amp, Manual, Model# SE-4022  







(66) 
Was $179.99 
Sale $159.99 
Save
$20.00

Poke around that web page.

So, you see, brutally expensive -- compared to a service call -- or a lost man-day... or NOT. 

You can re-wire this puppy into cranking out 28VDC. 

( Actually, 27.6 VDC is the peak ideal 

( Play transformer games... use a relay to maintain the original outputs.

( I presume you know how to run wire... etc. :laughing:

As for the number of times I've seen 'sick' lifts // dead batteries... I can't count that high. :no:

All it takes is a forgetful employee -- or a rude mechanical contractor -- who steals your power connection. 

&&&

Thirty-years ago I stuck my boss with a $190 tab for a brand new deluxe roll-around charger. Within the week, he used it three-times to rescue his own car, the Post Office's truck (!) and his own forklift. He never questioned that tab afterwards. A single service call for his ancient forklift was costing him $500. Those calls ended. They were resultant from its weak DC charging circuit. ( It had lots of starts -- with so little run time it could never recharge itself. Heh.

No-one ever complains about being able to service their own batteries. The bare bones units we all know are not sufficient to the task.

Once fully discharged, lead-acid batteries 'sulfonate' -- ie get coated internally. They can be rescued -- but only with the 'trick' battery chargers. ( Like my DeWalt -- see Walmart// Big Box Hardware. It's in limited production, only 50,000 units per month. ) 

So, you see, your headache is unique. :no::laughing:


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## telsa

lford250 said:


> sparkywannabee, thank you. When you say that it has a bad spot on the motor, what exactly does that mean? Do you mean it has a short in the windings? Or, do you mean that the brushes need to be replaced?


Bad Spot = a defective segment in and at the commutator.

This will also tend to chew up the DC brushes as fast as a T. Rex eating a carcass. 

Never buy a new DC motor without inspecting the brushes.

Contrary to prior advice elsewhere, *all* such motors provide instant access to swap out replacements.

Why is that? It's because they wear out, that's why.

You are not dealing with locomotive DC traction motors with brushes the size of your tush. 

The brushes within such a pump-motor get HEAVY use -- as they surge current with every motor start. There are _gazillion_ motor starts in a production work-day.

Its such surges that lead to commutator abuse -- and failure. These are the primary failure mode in automotive starters, too.

Do note the brushless DC motors that Milwaukee has brought to the mass market.

Why? It's because brushes are the weak point in a DC motor, that's why. :thumbsup:


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## wendon

Check voltage coming from battery bank.
Check voltage at motor when solenoid is engaged.
If the voltage is correct at the motor, try tapping on the motor.
If that doesn't work, get a bigger hammer.....


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## John Valdes

I go through this it seems almost every summer with my lawn tractor.
Since I started removing the battery, checking the liquid level and putting it on slow charge now and again for several hours, the problem has seemed to indicate terrible battery maintenance.
My bet is the batteries or battery.


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## dawgs

Check the motor brushes. Try tapping on them with a screw driver handle or something while engaging the handle. See if it will make a connection. Sitting that long maybe acquiring rust spots on the armature.


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## 3DDesign

Disconnect all the batteries and load test them individually like you would a car battery. If you have to, take them to someplace like Interstate Battery and have them test each one.


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## John Valdes

An ignored battery outside in the elements is going to be a bad battery before to long.
The comment "clicking sound" indicates it is the batteries.
3D is correct. Take them to Advance Auto or Auto Zone or similar and have each one checked.
I wonder if they will test this type or multiple batteries?


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## John Valdes

This thread reminded me to go down to the basement and remove my tractor battery from the machine, check the fluid level and put on trickle charge.
Thanks OP.


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## Helmut

sparkywannabee said:


> BTW, it could very well be a 48V system, they are most common.


Mine is. MEC 3030 Never seen anything but 48V units




sparkywannabee said:


> Check the main fuse right by the contactor, if its totally quit working now it might be blown, which would also indicate bad motor..


Maybe, Maybe not. Sometimes it's the cord that they run up to the platform. If that gets pinched, it'll blow the fuse. You gotta look at the wiring.


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## Helmut

If your chargers screwed up, and you don't have a smart charger installed, you can boil the batteries if you keep it plugged in.


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## degupita

Don't they normally keep scissor lifts inside? 
They don't seem like they are set up to be left out doors in the weather.

The first job I got a chance to use them, was good, because pretty much every scenario for riding and working with them came up. As we were running and installing the main service cable in the lower level parking area.

After that at other jobs, leads would let me do most of the work with them, because I could steer through pretty much anything.


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## John Valdes

Helmut said:


> If your chargers screwed up, and you don't have a smart charger installed, you can boil the batteries if you keep it plugged in.


Yep. Even a trickle charge with auto shut off should not be ignored for long periods of time.
A couple years ago when I first started addressing spring starting issues I bought an automatic trickle charger.
The instructions said it could be left connected for "long periods of time".
It did not say how long the periods were to be. 
That first spring, I found the battery dry and i had it leveled out before I put it on charge.
So, no matter the charger, you must pay attention.

BTW. I was able to resurrect that dry battery, but only got one season out of it.


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## TBinKC

*Motor check verified*

I have a similar issue with a Skyjack 3219 and after tightening up loose connections in the joystick, cleaning and zip-tying the joystick plug I was able to identify the motor as the source of the intermittent failure. Power was obviously getting to the solenoid since it clicked. It turns out that the motor has an exposed fan between the motor housing and the hydraulic pump. I was able to turn the blade with my finger then retry the controls. The motor functioned normally. I tried over and over until it once again failed. I turned the motor fan a little bit, tried again and it worked again. I hope this process can save someone a little time in fishing through all the other issues. I will take the motor out tomorrow and see if I can do anything to remedy the issue.


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## vunchan01

Hi all 
I have an old Upright scissor lift model 65600-000 serial 6674 will not move forward or backward but it goes up and down fine.
anybody know this kind of troubleshoot . thank advance


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## wcord

vunchan01 said:


> Hi all
> I have an old Upright scissor lift model 65600-000 serial 6674 will not move forward or backward but it goes up and down fine.
> anybody know this kind of troubleshoot . thank advance


First. Is thw charger still plugged in?

Some lifts won't drive if you are hooked up to 120


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## vunchan01

wcord said:


> First. Is thw charger still plugged in?
> 
> Some lifts won't drive if you are hooked up to 120


No plug it was work fine a few day a go. it is 4 battery


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## wcord




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## thejasonlee17

sbrn33 said:


> No you don't need that. Plug it in and check the voltage. It should be around 28 volts or so when charging. Water is a big deal. It is probably not the charger or batts but you never no and it is easy to eliminate them as a problem. It doesn't hurt to redo all those connections.


 Where do you ckeck this ? On one of the battery terminals?


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## Wardenclyffe




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## LGLS

thejasonlee17 said:


> Where do you ckeck this ? On one of the battery terminals?


Are you lost? Did you read the warning "For electrician PROS only and related" and thar doesn't mean forklift mechanics iy ya get my drift? If not no insult or harm intended... Welcome to the board if you are, but you may want to ask this over at WWW.diychatroom.com, our sister site, this is for pros only and... no electrician would ever ask that question... IRL. 

Nice "dad bod" BTW.... WOOF!


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