Grove AMZ-66 manlift--looking for help troubleshooting basket controls

Hi,

I have an older Grove AMZ-66 two wheel drive manlift. It has problems with the basket proportional controls where moving the joystick in either direction gives you movement in one direction only. The movement is a little slower when the joystick is in the opposite direction from what you are trying to command. This odd action does not stay there 100% of the time. Sometimes the joysticks seem to work for a short period of time but invariably go back to the one way operation.

The machine has an "OEM Controls" controller that seems to multiplex the proportional controls into one cable pair to transmit the command down to the receiving controller on the machine. The transmitter has the keypad and plug-in jack for earphones.

I have a service manual for a newer machine...mine is a 205XX serial number and the manual is a 836XX serial number. It was an eBay manual and so I got what I paid for...someone had removed the hydraulics/proportional section that had all the explanations I think I need to troubleshoot this puppy.

I can get everything to work from the controls on the base of the machine. All of the "on/off" controls in the basket work, too. I did notice that occasionally I had to mechanically poke a proportional valve up the butt with a screwdriver to get it to work...so they must be a little sticky.

I checked for a manual with the local Grove dealer in my area (Coast Crane) and they in turn checked with Minnpar....sure, a manual can be had for $499.95. Seriously. This is a "stump ranch" machine, not one that has to work in downtown NYC!!

I'm looking for either some kind soul with a manual who might be willing to photocopy or scan the manual section I am missing (for $) or to make suggestions and help me work to a solution.

Thanks,
Jon.

Success....

Hi,

I have a bit of good news to report on the problems I have posted above. I found a description of how to set up the joysticks in a Grove manual I had which, while not fixing the problem, allowed me to troubleshoot the problem and zero it in to the lower multiplex receiving box on the machine.

I'm posting this note so others who may have the joy of trying to fix a Grove AMZ or related model may find a little help here.

The service manual seems to be scared of these two transmit and receive boxes and for any problems they only say, "replace the box".

Yeh. At Grove (now Minnpar) prices. un-hunh. I'll be sure to order two of each.

I removed the lower box and opened it up. It had a couple of circuit boards covered in conformal coating, a clear silicon seal-like crap that makes working on anything in there the shzts. However, I noticed that the proportional part of the circuit had 5 small relays in it. The only moving parts in the whole box. I wonder...? Peering at the copper traces in the circuit board around the double pole relays suggested that they were set up as a reversing switch of some kind. EUREKA!!!

These little relays reversed the signal to each valve so that when you wanted to change direction with the joystick, the opposite side of the valve was energized...via the relay. They are standard Omron 5 amp relays so I had replacements ($9.00 each) in a couple of days from Digi-Key, a big electronics parts supplier in Minn.

Changing them out was no picnic, everything was covered in that infernal conformal coating and trying to get the 8 pins of each relay out of the soldered holes in the circuit board....well, it took some time and lots of solder wick.

But, once back together, the odd behavior of a joystick only moving an axis in one direction no matter what way the joystick was moved, WAS GONE. It now works correctly.

I pulled the old relays apart and was able to observe a very small area of arcing and pitting on one of the contacts on each of the 4 relays. I presume that this was the culprit in causing my particular set of symptoms.

Jon.

I'm still hoping that someone out there might have a wiring diagram for a Grove AMZ-series machine. I don't need a diagram for my machine exactly, (AMZ-66) but one for a AMZ machine that has the multiplexing transmitter and receiver. I'd be happy to pay for you to take it to a copying place to scan and email it to me...

Thanks,
Jon.

Hello,


I have a crane AMZ66XT. I do not know which are the differences from AMZ66.
My problem is that the crane was stored outside and the moment when I wanted to start, I noticed that all the cables from the terminal block connections from the control panel of the basket are removed. Looks like someone made ​​a really bad joke.
After the I said I do not know the differences between AMZ66XT and AMZ66, but if you can look at your crane and make a plan as cables are connected to the terminal block.



Maybe a picture inside the operator panel could complete this little scheme.
In preparing the scheme take great care of the 6 diode polarity

What is your e-mail address to be able to send diagrams that I have. Unfortunately for my model is not good.

I have several Grove manuals, including the AMZ66, and they do not seem to include wiring diagrams. At least nun of mine have them, the electrical section is 16 pages with very little info. In my opinion, Grove manuals are some of the worse written manuals out there. $500.00 +/- per machine and they tell you almost nothing.

Hi,

The difference between the AMZ66XT and AMZ66, to my knowledge, is that the XT has 4 wheel drive.

I think someone played more than a bad joke on you....I don't see the electronic transmitter box in there....my machine has the transmitter located beside the terminal strip. Does your machine have the transmitter and receiver boxes...? It seems to me that some models of the AMZ may have some electronics built into each joystick and don't use the transmitter/receiver setup. I'll take a photo of my layout and post it here so you can see if my machine is set up similar to yours.

If my setup can help you I have no problem making a listing for you of the wire numbers and where they are connected.

Excavator, you say a mouthful... my manuals aren't so useful, either. I have a manual I borrowed from a friend with an AMZ-50. He has a whole bunch of electrical drawings in 11 x 17 size but I think he asked for them from a Grove dealer here in BC, and since he has several cranes I think they pulled the stops to help him. They aren't much good for me because they are for a unit that is not blessed with the electronic transmitter/receiver box.

Jon.

Hi, I'm new here, we have an AMZ-50 with electrical issues, none of the boom controls work from the basket. Was wondering if sawmilleng still had access to the AMZ-50 manual, and if he could share any info with me. Thanks

Hi, Limorsteel,

I'll see what I still have of the AMZ-50 info. I'd be happy to scan anything I have and email it to you. I can only scan 8.5" wide and I think the drawings are 11 x 17 so I would have to either get them scanned by a commercial place at a few bucks a copy or see if I can scan sections that you would have to paste together...

From what you are saying, if NONE of the boom controls work from the basket you might have a problem where the entire cable is either unplugged or severed somewhere within the boom.

For your information, I managed to purchase a "hydraulics and electrics schematics" set of drawings from Minnpar for my AMZ-66 for $160 or so. It was 3 pages each of hydraulics and electrical schematics in 11 x 17 size. It illustrates all the wiring on the machine EXCEPT for any details of the upper and lower transmitter/receiver boxes. But if your AMZ-50 doesn't use these two boxes you will have the complete wiring diagrams. And since they will ask for your machine serial number, you will get the exact wiring diagrams that are for your machine. Worth considering.

For others looking at AMZ-66 problems, my issues have not disappeared. In posting #2, above, I said that changing some little relays in the lower electronics control box made my problems disappear. Yeah, for a day. The same symptoms came back and are still there. I've been busy as heck on other things and cannot dedicate time to thoroughly troubleshoot the problem. I need to use the machine on the farm nearly every day so have to have a groundsman around (my wife) to help-- from the ground controls-- with movements that the machine won't cooperate with at any given time.

Working at troubleshooting this has been kinda fun in a perverse way... I'm a mechanical engineer and one of my sons is going to college for electronics technician so we are getting loads of quality time discussing the issue and coming up with ideas for troubleshooting to try to narrow the problem down. While avoiding putting the machine fully down for any length of time! That's the one bright side to this machine's problems.

Gads, I can't begin to imagine the frustration of someone who was trying to keep this machine running for a real business, where downtime is critical. It would have been shipped to the scrapyard and turned into Toyota hubcaps years ago!!!

So I'll have a look tomorrow of what I have and get back to you.

Jon.

If you have not done so, clean all of your grounding points. On my MZ145, grounds are inside upper control box, inside lower control box and there are a few grounds to the frame bundled on a starter bolt (these may be the most important ones). Your ground points may be in a different location but find them, remove the lugs, file the grounding point clean and file the lugs. Look for loose crimp fittings in the lugs. Use dielectric grease when putting it back together.

The MZ145 has a signal led on the lower control box that indicates there is comm with the upper control box. It flashes. If your model has this, does it flash? If so, cabling is probably not your issue unless it's intermittent.

Again, if your control box is like the MZ145 and I think it is, there is an axial capacitor on the upper control terminals. Replace it. It's a .50 cent part. Check the diodes across the terminals in the upper controls with a multimeter. With one end of the diode lifted, it should be open on one direction and have resistance in the other direction.

There is no magic bullet in fixing these things. It's more like unwinding a series of unfortunate events. Start with the grounds.

Hi, GBH,

Not sure if you are talking to Limorsteel or me, but your comments are very interesting.

I've checked the grounds on the lower control box that passes through the box to a big ground wire on the outside of the box. Changed the bolt, sandpapered, used Penetrox on it because of the steel/copper/aluminum joint. We'll chase down the other grounds you mentioned and deal with them.

I've had a look at the voltage at the upper control box. It seems to be kind of low--11.5V or so when the lower box voltmeter is reading 14V (while the engine is running and the alternator is charging). So--even more important to check all the grounding.

The comm link flashes--I'm pretty sure the two boxes are communicating. I've tried a separate cable for the comm link to see if anything changed. No joy.

I've looked at the capacitor and diode on the upper box power supply and wondered if that old electrolytic capacitor could be contributing to our problem.... Now that you pointed it out, we'll cover that point off.

I picked the machine up out of a boneyard in a big plant in Ohio. I'm guessing that they had the same problem as I'm working on and finally tossed it, out of frustration.

Is your MZ-145 a 145 footer? Pretty big machine! My knees would be knocking when passing 60 feet going up!! It would make one heck of a fine elk blind here on the farm! You could just drop rocks on their heads when they were grazing on the hay under you!!

Jon.

My MZ145 is 45 feet. The vertical reach is fine for what I do but the horizontal reach can be a bit limiting when I can't get the lift close to whatever I'm working on.

Let us know what happens after you chase the grounds.

Grove AMZ-66 basket control issues

I am pulling out my hair with a 1992 Grove AMZ-66 manlift which the controls from the basket do not work. Only the emergency stop, starter switch and choke switch operate from the basket. Yesterday, I had all of the lower control functions working and today only half of them are operational. On the low side, the steering works, the boom in/out works. I can operate the boom lift, swing and fwd/reverse by pushing in on the solenoids.
Now on the lower controls, when using the basket tilt, it pressurizes the hoses but doesn't move. (it did earlier in the day)
I'm no electronics expert but have a meter and know how to use it. I cleaned a few connections but overall the wiring and boxes appear to be in good order. The lift functioned about a year ago and has been sitting since. No rodent damage and it has been sheltered.

I found a little "lunar lander" device under the engine next to an alarm horn that had some nasty wires on it. What does this device do?
Any ideas? I have a parts book but no manual.

Fear,

If you can't get any action by poking the valves, then your problems are not electrics.

I'd start by ensuring that your oil tank is full on the sight gauge. Don't ask me why I know this is important!!

Then get a hydraulic gauge good for 3500 psi and plumb it in on the pressure line from the pump. There's a spot for it under the electrical control box, right by the emergency electric pump. It's an o-ring face seal type of fitting so you'll need an adapter to fit your guage, which will likely be 1/4" pipe threaded.

The pump is a pressure compensated pump where it adjusts the flow to a set pressure. You should see this pressure once you start up. I'm not exactly sure but I believe it should be around 3000psi.

If you can get the boom in/out to work but none of the other ones, it sounds like you may have low pressure, since the boom in/out doesn't take much pressure to operate. Low pressure may also be your problem with the basket tilt, since pressure has to overcome the cross port relief valves to move the cylinder.

Another angle to check would be to try using the system with the emergency electric pump. Will it make any or all of the functions work?

Hope this helps!

Jon.

The electric aux pump does make the functions work for the most part.
The boom in/out isn't the only thing that works. The boom lift works with manual stimulation, the wheels drive, the boom swings, etc.
There is absolutely no hydraulic actuation from the basket. (Not even trying)
I can check the pressures but pretty sure this isn't the issue unless it has to be at a higher value for the basket controls to work than the lower controls. Yesterday, I had every control working from the lower panel and gradually things have deteriorated from there the more I've tried to "fix it".
Even when all the lower controls were working, there was NO actions from the basket (other than engine related)
None of the circuit boards look like the magic smoke got out. Just don't know how to go about troubleshooting this...
I'll try to come up with a gauge and tap in somewhere...
I appreciate your input.

I've got similar problems to you with my AMZ-66.

With the exception that all of my lower controls work. The valves are sometimes sticky but with a few manual pokes up their butts and with warmer oil the lower controls work.

The upper controls operate the same valve coils except that on the proportional controls the current is pulse width modulated. The lower controls just turn the valves on, to the level set by the lower potentiometer.

So if you can't get the lower controls to work I wouldn't worry much about getting the upper to work. Do you have the upper and lower transmitter/receiver setup? My AMZ is mid 1980's and I think they may have toasted that control setup in later models because it was hard to troubleshoot. It used a single twisted pair of wires to send the switch commands from the basket down to the lower controls. It could handle something like 13 or 14 on/off switch commands and 4 proportional commands from the upper basket.

I believe a few of the upper controls were hard wired on different wire pairs...for example, the e-stop is hard wired and likely your starter and choke are, too. I'll bet your emergency hydraulics button is also hard wired from the basket.

If your lower control electronics box is the same as mine it has a test lead and a red light on the box. You can check to see if the box is outputting power to the appropriate solenoid terminal when someone is holding the basket control on.

There is also a red LED on the front of the box that shows if the box is receiving a signal from the upper. It should be flashing if it thinks things are OK.

Jon.

I picked up a hydraulic gauge today 0-5000psi and will try to get that plumbed in to check pressures. It will have to wait a bit as it's too stinking hot to be outside this afternoon.

Went back at the Grove AMZ66 today and here's what took place:
1. I couldn't figure out where to tap in for a gauge. Guess I need more specifics.
2. I cleaned the hydraulic filter (looked good) but in reinstalling the canister, it must have shaved the large o-ring as it leaks now.
3. I checked the aux controls (the ones that run off just the battery and drives a starter motor turning a separate hydraulic pump. All of the functions worked with that system.
4. I fired the unit up and was experimenting with labeling solenoids to try to isolate why I lost some functionality of the lower controls. I finally figured out that if I turned the rate control up more, I got those functions back. So with the control dial up towards the higher side, I now again have all the lower controls functioning. So hydraulics probably isn't my issue.
5. The exception to "everything functioning" is the basket tilt. This was working a couple sessions ago but it is either seized up or something is stuck. When I try the tilt mode in either direction it loads the engine and I can see the hoses flexing as they're pressurizing but the basket doesn't move. It is almost like pressure is being applied to both sides of the actuator cylinder at once. At this point, while it will need to get resolved, that isn't my top priority.
6. The indicator light in the lower control electronic panel which is supposed to be flashing if the basket is communicating wasn't. I messed with a bunch of wires unplugging and plugging in connectors and generally inspecting them. I checked the light and it seemed to be flickering. Not really "flashing" but more like vibrating if that makes sense. At any rate, it looked different so I went into the basket and lo and behold, the basket controls worked. I was in there testing different functions and then nothing was working again. I checked the indicator light and it was steady again. Rats! So I started messing with wires again and found a few that didn't look all that great. Wish I knew which "pair" of wires supply the signal to the lower panel. I was unable to get the light to flicker again but quit as I was getting overheated.
So I made two steps forward and one step back but at this point I think I have a wiring issue and not some electronic issue so that is somewhat encouraging. I need to solve the hydraulic leak created at the filter but in a worst case scenario I would let this leak if I could get everything else functioning.

Hi, Fear,

Sounds like you had a productive, if a little frustrating, day.

I agree with your conclusion about probably not having hydraulics issues. And you probably don't have electronics issues, either.

I read your comments about just how the flashing led works with some interest, since my issues are very similar to yours. I have been working under the assumption that the faster the led flashes, the better the signal. Anyway, my led has been flashing very fast, almost steady. So your saying that your system quit when the led was steady has me scratching my head.

To find the twisted pair of wires that is the communications link between upper and lower, take a look at the wire numbers on the comm terminal strip along the bottom of the box in the lower. It is right beside the power supply terminals. Those same wire numbers will show up in the upper box on the terminal strip. My drawings, which are specific for my machine, suggest the numbers are 37 and 37A. It shows a shielded twisted pair is used for this link.

I tried bypassing the comm wire pair on my machine by pulling off the wires on the upper and lower and taking a long chunk of 16 gauge "extension cord" type of cable. There was no change for me...the led blinked at about the same rate and no changes were seen when trying to use the upper controls. This could have been a bad test...I didn't use a shielded cable for the comm line.

You might have a close look at post #9, from GBH, where he suggested cleaning all the grounding points. I have not tried that yet on my machine. I did take a look at the voltage available at the power supply for the upper and it wasn't the best- around 11 volts when the machine was running, with 14.4 volts coming off the alternator. However, there are some power resistors in the dc supply to the upper so I'm not sure if the lower voltage is a problem or not.

Regarding your basket tilt issue, do you have an 8' basket? If so, it has an additional electrically-actuated lock valve on it. If not, the hydraulic schematic is pretty simple and I can scan it to you. If you can feel the hoses stiffen under pressure then it sounds like there's a bad counterbalance valve or like you say, something is seized or plugged.

Jon.

I'm about ready to call the scrap man on this unit. Seems like I just keep going backwards...
The latest issue is that I lost electrical to the ignition system. ie, when I turn the key on, it doesn't register on the voltmeter and there seems to be no power to the coil. However there is when I push the aux controls button. Must be a relay somewhere that packed in. I just don't have the time to spend on this unit and am going to give it one more go and then I'm gonna quit. Grrrr!

Fear,

Calm down... Its only a machine...! But I would be there with you if you decided to shoot the engineer who designed the electrics on these machines with balls of his own shzt! :Banghead

I think you might benefit from getting an electrical schematic. At least you can then go over what you've done and see how it fits in the big picture.

I'm wondering if you might be fighting with grounding issues...

Jon.