Hello, new to the forum for posting but have been lurking around for a bit. I have a 1996 Genie s40 gas boom lift, I have some issue to work out. It currently has a turntable rotation issue, it will rotate from the ground control just fine, but from the basket the rotation is only max speed not matter how little you move the stick. Speed from the ground is normal. I tried adjusting the trim pots but there was no change in voltage so I assumed they were bad and replaced the joystick and control boards. The new one does the same thing. I am starting to test grounds and potential power issues at the basket but if anyone has any ideas hit me up!! Thanks!!
Update on what I have tried to solve this. I have ran a temporary power and ground supply from the battery to the basket to see if there was a voltage drop issue in the boom harness, this made zero difference. Still no change to the output of the control. Not sure what else could be causing this. I have made a temporary solution to the fast rotation of the turntable by installing an adjustable dc to dc converter before the flow control solenoid and dropped the voltage down to slow turntable rotation at the basket controls. This will allow me to use this unit safely to complete the job I need it for. I would still prefer to solve this issue. But time was running short. Please if anyone is familiar with this system and had any ideas that would be great. I am at the point of having to pay for a genie tech to come and diag.
I'm not familiar with the S40 and the components that they used. You need to download the service and parts manuals for you machine serial number from the Genie website, the service manual has the procedure for adjusting the joysticks. As for voltage output, can't rely on that because the proportional output of those joysticks is Pulse Width Modulation, can't see that with a volt meter.
I have the service manual, and the adjustment procedure calls to use a multimeter to read the voltage output at a specific terminal and adjust a potentiometer to set it to a specific voltage. This is what doesn’t change. So something is going on to stop this voltage from changing. This was the same with the old joystick as well. I thought the pot was bad which is why I got a new joystick. The joystick will read correctly on the boom up and down side. That’s what is stumping me.
Yes, with the old OEM style controllers the procedure was to adjust to a certain voltage output because that's really the only way to adjust them, but what you can't see on voltage is the actual proportional output of the controller, which is PWM, can't see that on a volt meter. Typically, you back out the Ramp adjustment screw several turns, 10 to 15 turns, then you adjust the Threshold, which is the point a function reacts when you move the joystick off center. Then, on some controllers, you adjust the Max Output, controller fully stroked. On others there's a Low output and a High output to adjust. The last adjustment is the Ramp, which is actually more like an "off ramp", like, engine running, engage boom lift fully and release the control lever so it springs back to center, the Ramp adjusts how quicky the boom up, in this case, comes to a stop. Abruptly and it will bounce you out of the basket, properly adjusted the boom will stop raising in a controlled and smooth "off ramp" speed. But back to the speed adjustment, wheter it's just Max or Lo and Hi, you should see a change in the volt meter when you're turning the trim pot screws making the meter go up or down to hit the spot Genie recommends.
Yeah that’s the strange part I get no change on the voltage no matter what I do with the pots.
And the voltage is way higher than the manual calls for, manual calls for 2.5v when just engaging the joystick and 5.5v at full left or right and I have 8.5v. Just engaging and no change a full left or right.
Yes, I get that. I'm asking do adjusting the trim pots make it drop? If not, you have a faulty controller. Those things can be easy to adjust or if the trim pots are way out of sync, they can be a PITA. That 2.5V sounds like threshold. On old style OEM controllers, which is what I assume you have, there are LED light on the circuit board that light up as you move the joystick away from center. The very moment you see the LED light come on as you move the stick, hold the stick right there and adjust the threshold trim pot to 2.5V. If you don't get that, you have a faulty controller.
That was my concern even though I had a brand new joystick and control boards. So I swapped the board that doesn’t change with the boom up/down that I know was working and I get the same result. No change when moving the pots. Is it possible that I just wasn’t making enough of an adjustment to the pots? I didn’t want to just keep turning them as I didn’t want to damage them.
The only other thing you mention is that when steering the drive axle it moves really slow like non existent movement unless you boom in or out while trying to steer. I also noticed that the flow control solenoid for the turntable rotation has 12v whenever the key switch it on basket controls. When on ground control it only has 12v whenever the rotation switch is activated.
You should only see voltage at the proportional flow control when you work a function, that's not right. What's your machine serial number?
Serial is 610
Wow, she's an old one. LoL. What engine? 2wd or 4wd?
Yup 1996
So something must be back feeding that solenoid.
What engine? 2wd or 4wd?
4wd with the ford engine
Got it.
I need to clarify post #9 where you swapped the circuit board with the boom up/down board. Did that make the boom up/down full speed as well?
No I took the old board that I knew was working in that function and put it in place of the new one to see if there was any difference. Was worried that I got a bad card.
That's what I wish to clarify. What I'm reading is you swapped the board for swing with the board for boom up/down. If I'm reading that right, what was the result?
Same no change in voltage when moving the pots.
You've stated that, but that's what I'm not clear about, did the suspect faulty board make the boom up/down wonky once you made the swap? Or was boom up/down working normal like it was before you made the swap?
And what about the swing, what change happened there?
Swing was still full speed, boom functioned as normal as it still had a new board. So all I did was replace just the swing board with the original boom up down board. At this point I have two sets of cards. Not sure there was anything wrong with them. If that solenoid isn’t supposed to have power till you activate a function then that is probably my main issue.
Ok, that's what I needed to know. You have swing that is full speed in either direction, no proportional control. You have boom up/down that works normal, proper proportional control. You swapped the boards for swing and boom, boom still worked proper, swing was still nuts. Is that about right?
Yup
I am going to go over the wiring schematic today and see if I can trace the supply to that flow solenoid to see if there is something causing it to have power all the time.
Good news! At some point a prior owner had done some repair work to the wiring at the basket and had a wire on the wrong terminal of the boom in/out switch, this was back feeding 12v to the flow solenoid when the switch was on basket controls. I moved the wire back to its correct location and now I can adjust the pots and rotation functions as it is supposed to. The only question is why the steering is behaving weird. But I can work with that for now. I do suspect the joystick on that as it’s very corroded in places. But the manual doesn’t go into much troubleshooting for that issue. Thanks for you help.
Well, I was headed that way but had to log out last night. According to the schematics for your machine there's two proportional flow control valves, one for boom up/down, the other for swing, but the flow control valve for the swing is also shared by the telescope to provide oil for that function. Of course the telescope is a toggle switch, which would give full power to the flow control. And yes, incorrect wiring at that switch is going to be a problem. Glad you got it sorted out, and learned a little more about your machine in doing so.