Fabtek Computer

[deastman]

Ever since I've had my processor it hasn't been measuring right in reverse about 90% of the time. I put a new encoder in it when I got it so I don't think that's causing the problem. I'm thinking it must be in the computer but I'm not sure where and what to check, and I don't want to damage it. Anybody else ever had this problem?

[Southside]

Deastman,
I am still learning about mine, so I can't offer much help.  Could it be log slippage?  Do you have one encoder or two?  According to my wiring diagram I should have two, but the head only has one.

[deastman]

Mine is supposed to have 3 encoders but I only run one in the independent measuring wheel, I don't have the feed wheel encoders hooked up. I think the problem may be in the computer because it seems to measure ok forward. I've never done any repair work on the computer yet so I'm tryin to figure out where to start.

[leeroyjd]

Is your spring broke on the measuring wheel? I think I noticed more measuring backwards when it was broken.

[jdament]

My guess would be that if it reads good forward and not in reverse that the computer is ok, or it would read wrong both ways.  The computer doesn't care whish way the wheel goes it is just looking for the encoder pulses.  I would check the independent wheel bearings.  In forward the wheel trails so there is little drag but in reverse you push up on the wheel and if the bearings are bad the wheel will skid on the tree.

[deastman]

I rebuilt the whole independent measuring wheel when I got it. New encoder, new bearings, put on the new style measurin wheel, new spring and linkage, resealed the cylinder on top, and a  new pin and bushing for the arm itself. A couple months ago I noticed the spring was getting a little soft so I shimmed it with washers to stiffen it back up. I just checked it and everything is still ok, spring isn't broke and the bearings are all good, that's why I'm thinking it may be in the computer. Sometimes it doesn't measure right in forward but that doesn't happen very often.

[Southside]

Have you checked the wires and actual voltage pulsing through them?  I had a low voltage situation shortly after I got my machine, the alternator had died and the batteries were slowly draining, it did some very, very, strange things, voltage was down in the low 20's, after the charge was back things were back to normal. 

Where did you find your parts for the independent?  I would like to add that to my machine. I stopped into the local Deere dealer Friday for some seals for the rotary manifold and asked about the Fabtek components - they had no idea what I was talking about. 

[deastman]

I havnt checked the voltages yet, that'll be a good place to start. Caterpillar bought out Prentice, who had bought Fabtek, so Cat owns the head now and you can get any parts you need thru Cat.

[jdament]

I suppose it could be the chips in the computer. Mine would lock up but now after I pit in the memory chips it reads better than it ever has.  Amazingly it is even more accurate now.

[deastman]

That sounds like what might be my problem. Do you get the chips thru Cat or do you get them aftermarket? Looks like mine has three white chips and four red ones.

[jdament]

My machine is a 2000 fabtek and I have the older computer.  My keypad did not have a dial on it.  I replaced what they call the Dallas chip which also works as a battery for the computer and I replaced the other memory chip.  You have to get them from Cat.  I would think if your local Cat dealer is a forestry dealer they would have them.  I figured they must go bad if the dealer actually stocks them.  They were a pain to put in.

[deastman]

Thanks for the help,  I changed the Dallas, memory and Fabtek 4.0 chips and that solved my problem. It measures right in both directions and is also more accurate now. You weren't kidding about them being a pain to install, very aggrevating and time consuming.