# Upper Controls won't rotate boom Altec am600h



## tylerk (May 30, 2018)

Hello guys, I've done quite a bit of googling and research on the topic, and after being unable to find someone with my exact or similar problem I felt I would ask the question directly. All the forums I could find the issues were quite similiar, sluggish controls that stopped working, or the upper boom raising but not lowering. My issue is only with the rotation of the turret from the upper controls. It will not turn clockwise or counterclockwise even a smidge from the upper controls, however from the lower controls it works just fine.

The truck is a 92 Gmc Topkick with an altec am600h overcenter boom around 55ish feet. So all the controls in the truck work fine from the lower controls, and both booms also raise and lower from the upper controls. The only issue is the turret will not rotate from the upper controls. I have a feeling I'm overlooking something, but I'm just generally looking to get pointed in the right direction.

It has 3 settings at the lower station, upper/lower/purge.


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## benjo75 (Jun 9, 2018)

I have almost the same unit. I had that problem early on and it drove me crazy.

Problem 1. My canvas that covers my joystick control was torn. That allowed sawdust to collect around the spools below the joystick. Still I have to loosen it up with a screwdriver and blow it out with the leaf blower about once a month. 

Problem 2. The set screws on the spools below the upper controls can loosen up and are not being activated by the joystick.

Problem 3. The cable in the hand grip that activates the safety will stretch and the controls will gradually get slower until one direction stops working. I replace mine with equivalent size cable from Tractor Supply. Tie a knot in one end and a cable clamp on the outer end for adjustment. In other words make sure the joystick is working the spools beneath the joystick. If it is working them then you should be able to see the lower levers moving while you're working the upper controls. The upper control actually just uses a low pressure system to work the lower controls.

Problem 4. This is what mine turned out to be. I had recently used the lower controls. To this day when I use the lower controls it can still mess up my upper controls. First rotate the three way lever to purge. While in purge, work the 3 lower controls back and forth several times each slowly one at a time. Then move the lever from "purge" to "upper control" to "lower control" several times. This is what fixes mine now. I know I shouldn't have to do this but mine is an older unit and it has some tricks to it. The first time it acted up I had to clean out the valves that the lower controls operate. On mine, they are directly to the left of the lower control levers.

This gets kinda technical. Easy to do but very easy to mess up. I had to take a couple of hoses off for clearance. Looking at the valves, there are obviously three, on the far left side, the opposite side of the actual lever there are the end caps. Mine look like the end of a bolt with a jam nut and an Allen head in the end of each and big jam nut It's best to pressure wash before removing any lines or caps. Take the cap off of the end. I believe there are 2 Allen bolts holding it on. Be very careful doing this. I lay down paper towels as best I can. Behind this cap there is a spring and a little steel ball. It's not really under much pressure. After the spring comes out the ball will usually remain about an inch inside. If you loose that little ball you will be making an order to Altec. Use a little telescopic magnet and retrieve the ball. Place it somewhere very safe. I use either brake parts cleaner or WD 40 and spray in the hole while working the lever. One tiny piece of crud will keep the ball from sealing shut. If that happens the upper controls will simply bypass and not work that particular lower control. Spray it out good then blow it out with air. When clean, reinstall everything. I do one at a time, from top to bottom. I've only had to do this twice. Once I saw how it worked I realized that setting the lever to purge and working the lower controls does the same thing so try that first. I know this sounds complicated but it's what I went through the first time I used my lower controls then tried to use the uppers next. Took about a week and several calls to Altec to figure this out. Hope this helps.


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## tylerk (Jun 11, 2018)

benjo75 said:


> I have almost the same unit. I had that problem early on and it drove me crazy.
> 
> Problem 1. My canvas that covers my joystick control was torn. That allowed sawdust to collect around the spools below the joystick. Still I have to loosen it up with a screwdriver and blow it out with the leaf blower about once a month.
> 
> ...



Thank you very much for all the information, I will try some things out and post the results.


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