for a non-tech zippin seems to have a good grasp on how to deal with these trucks
as he said the control handle is pretty straight forward, its mainly mechanical with 2 potentiometers that are usually the problem when things go wrong with the operation of the truck, simply relearning the system or replacing the potentiometers and then relearning the system will fix these issues.

And again on the TMM part, the truck shutting off when you 'tap' on the TMM only tells me there is a connection issue somewhere. Like zippin said, closly check the db connections and make sure they are tightened all the way and you can also remove the TMM and dissassemble it and check for loose connections inside with the ribbon cable connecting the power dist card etc.

But as been said before, if you are not familiar with this truck this will be a learning experience for you (possibly a frustrating one at that) , get the manuals if your plan is to maintain and repair this yourself, they will help somewhat.

good luck

I am not a forklift tech, but I have three of these that I service myself regularly. I have learned a lot from these forums and I have a set of factory manuals. That said, I agree that the diagnosis on these can be tricky. I have had factory trained and experienced Caterpillar technicians look at my forklifts for electrical problems and be wrong, at my expense. Following a common sense approach to these is the smart thing. Also, verify everything. I have had joystick trouble as well. The joystick as a whole is a mechanical mechanism that as you stated can wear out, but typically all that goes wrong with these is usually the Potentiometer. If your trouble is sluggish control or erratic behavior, I would do the relearn procedure mentioned first. It is not as difficult as it may seem. If the symptom persist's and the mechanical components are not worn out, I would replace the Potentiometer and repeat the relearn. On the shutting down, if you can tap the board and make it shut down, disconnect the battery, take the connections loose on the board one at a time, inspect and clean them. if you see any corrosion or damage replace the damaged component. These are sensitive to voltage variations. They may be very simple, but they are logic circuits that function on low voltage signals. A.5 volt variation from bad or corroded or even loose connections can easily confuse the system and cause it to shut down. These circuits are very expensive and I would not replace them without some guarantee that the component has failed. There are some on board diagnostics available for much of these that will help you diagnose a bad board. A board sensitive to impact or vibration suggests that a connection is the likely culprit. As previously suggestted, a bad cable is more likely than a board and if a board has failed, there is likely a reason such as a weak or bad battery or cable. I tend to analyze the problem logically and plan a diagnostic process from that. Not always successful, but more often than not I find a simple solution I might have missed if I had jumped to the quick fix part replacement. In the automotive diagnostic world the rule of thumb is that the basic or simple problem is the likeliest, so stick to the basics and look more complicated only when all else fails. Obviously the technician that has seen these problems before has the best idea where to look. I have not had the shut down problem, but the joystick troubles I have repaired every time with a relearn or Potentiometer replacement. Incidentally, all these parts are readilly available from most any Caterpillar forklift dealer and there are many forklift parts suppliers that offer genuine Caterpillar parts. My dealer is as reasonable as the aftermarket parts, so I stick to the genuine Caterpillar parts with great success.

there are "learn in" procedures for the control handle that someone with training will need to do.
It may be something you have the physical ability to do, but this is like asking a 10 year old to clean a loaded gun, or capture a live shark, rabid dog or alligator without instructions. We kill about as many people every year by animals or by gun cleaning accidents as we do with forklifts, in the USA.
This really is one of those spots that having the tech who did the diagnosis to be who is responsible to insure the job is done correctly. Since it was determined to be a 'high dollar' part, your boss would be far more penny wise (and -not- pound foolish) to expect the troubleshooter to stand behind the diagnosis.
When this truck "randomly shuts down" does it show ANYTHING in the dash? no codes? and you can always turn the key off and on again to get it running? and it runs fine after cycling the key switch?
If you had me doing this troubleshoot, and I had no idea of the history of the cable in the mast, I would suggest the most likely places for this 'Weird Intermittent Failure' (WIF) to be the mast cables, as they twist and bend more than any other cable on the truck, and can break the cable conductor internally but not break the insulation. but if you have NO codes, then I would be looking at the key switch.

We had a tech come out and he found the problem with the card. Let me just say I in know way feel qualified to diagnosis any problems with this lift. The lift just randomly shuts off so he felt the card was doing it. He tapped on it and the lift shut down so he believes thats one of the problems. The control stick is warn out and needs to be replaced also and it doesn't seem to be that difficult a fix (Im sure Im wrong probably a nightmare). If it were up to me I'd have the tech fix it but the boss feels this is something we can do. Im just looking to gather info to present to him pros and cons in doing it our self's.

first off i would like to say unless you have had experience with these trucks your diagnosis most likely is incorrect on the TMM card issue , that is unless its burned or something.

Also that TMM card assy comes in 3 parts, the power distribution board, the power supply and the logic unit. You can replace the whole thing if you like but that is an expensive replacement. Also you will need to know what software version in the TMM you have(if you replace the whole assy or replace the logic card), provide battery voltage, a truck model and serial number when ordering, there should also be a tag on the TMM assy with numbers on it. The software version can be obtained by accessing the system and scrolling to the correct menu.

on the control handle , they do offer reman control handles that are slightly less costly than the OEM new.

You can contact Wiese they are the Cat dealer in your area and will either have the parts or can get them for you.

Their website is www dot wieseusa dot com