Fabtek 4 Roller Issues Again

[Corley5]

Got the machine running again and everything seems well with the engine's fuel system.  A problem has started with the head.  The bar doesn't always return home.  It'll be fine for a couple hours and then without warning it quits going back reliably.  It doesn't start gradually it's all at once.  I can blip the saw button and get it to return and one day if I sat in the cab looking at it long enough it would all of sudden go back on its own.  Sometimes it will work fine for a couple cycles but a couple cycles only.  It seems to start when the hydraulic temperature gets into the mid 120s.  We replaced the bearing behind the saw sprocket which was bad but not terrible thinking that might be binding and causing the problem.  Didn't make any difference.  I switched the relays around in the computer box and that didn't help.  So I'm thinking the problem maybe in the manifold block on top of the saw motor.  There's some debris in there that starts to float around when the oil thins out...  Maybe  ???  Any ideas  ??? 

[snowstorm]

or the spool is sticking when the oil gets warm. electric valve? weak magnet?

[deastman]

Is the accumulator pressure up to spec?

[lopet]

I too would bet on a weak magnet, but only saying that could be  a problem. ;D

[Corley5]

  We pulled the manifold off the top of the saw motor today to take to the shop tomorrow.  I think it's where the problem is  ??? but am not sure.  I ran the machine a couple hours today watching the hydraulic temp and it was at 133 degrees that the problem showed itself again.  No warning, nothing gradual.  Once it starts that's it until the machine cools off.  I don't know how cool it has to be before it will work properly.  Overnight is what I've tried  ;) ;D
  The manifold is fed by two 1" 4 wire hydraulic lines.  The saw motor, feed and return for the saw bar, and chain tension are all controlled from this block with the oil from the two large lines.  Two lines go out to the cylinder for the bar, two for the tension and there's a 5th line that I think is pilot pressure  ???  The pilot line ??? comes from a block at the bottom of the head which has two lines that go to the roller motors.  One goes to each roller motor.  There's a manual flow control to set the saw feed speed, and what appear to be three relief valves.  Anyway it's off and going to see the Dr. in the AM.  I'm not sure it's the problem but it's as good a place as any to start.  Someone has had it apart in the past judging from the wear on plugs maybe several times.   
  There are no wires going to the block.  The only wires in the area are for the proximity switch but they have no connection to the hydraulics in the head. 
  The valve that controls flow to the saw manifold is on the carrier and controlled by the switch on the joystick.  I think it's working fine as the circuit is complete when the saw is running and the saw works fine.  The power and speed are what they should be and the oil is going back to tank.  The only accumulator on this head is for the third or independent measuring wheel and there's no connection to it from the saw circuit.  The accumulator is clamped at the bottom of the channel of the main frame of the head opposite the saw.   
 

[1270d]

I had this same problem happen but on an H480 head.  It had a pilot valve to control bar feed that would get very small pieces of metal stuck inside occasionally.  The problem seemed to crop up after blowing a hose on the head, which must have put a few wire fragments into the valve block.  It would sometimes fix itself by blipping the saw button a few times.   Otherwise the valve had to be pulled apart and cleaned.  Let some oil flow out to help flush the block, and if there is a vacuum pump, don't use it.

[lumbertick]

Mine started doing the same thing today... One of us will find the problem

[Corley5]

  Dropped the block off at the shop this AM and it was done after lunch.  Scott put all new seals and backers in it and thinks he found the problems.  The flow control that controls the bar's feed speed was missing all its O-rings and nylon backers.  A jam nut was also missing on a relief valve and it had backed out and was loose.  The concern now is where is the debris from the missing seal parts going to end up and what problems might they cause down the road  ???  We'll put the thing back together in the morning and see if the problem is fixed  :-\
  Hope this works Lumbertick  8)  

[BargeMonkey]

  Dropped the block off at the shop this AM and it was done after lunch.  Scott put all new seals and backers in it and thinks he found the problems.  The flow control that controls the bar's feed speed was missing all its O-rings and nylon backers.  A jam nut was also missing on a relief valve and it had backed out and was loose.  The concern now is where is the debris from the missing seal parts going to end up and what problems might they cause down the road  ???  We'll put the thing back together in the morning and see if the problem is fixed  :-\
  Hope this works Lumbertick  8)

I hope you get it fixed, but the problems i see you guys have with the harvester's / heads kind of scares me sometimes.    spend a pile of money quickly.

[lumbertick]

Corley5 let me know when you get it going thanks

[Corley5]

After exchanging messages with another member I just ordered a new proximity switch.  It'll be here UPS tomorrow.  I won't know for sure what fixed the problem if one of these measures does fix it but it's easier to do it all now.

[lumbertick]

Did you check the electric sylinoide on the valve bank? I just plunged mine manualy and it is working fine now

[Corley5]

We got it all put back together this afternoon and will give it try tomorrow.  All the functions work as they should but we won't know until it's hot whether it's fixed or not.

[Corley5]

Ran five hours today with no issues.  I'm willing to bet that the culprit was the proximity switch but can't be sure.  Nothing got fixed that wasn't in need of fixing and one of those fixes fixed it  ;) :D ;D  I've got some hydraulic leaks that need attention now.  That's never ending ;D

[lopet]

Good to hear you're cutting wood again.

[lumbertick]

Put the new saw prox on mine this morning and it fixed the problem.

[monkeywrench]

fabtek2000 harvester ; seem to have computer problems will cut a few trees then will stop measuring turn computer off and on will be ok for another while before it happens again. any help will be appreciated.

[Firewoodjoe]

Independent wheel? Does the numbers just stay 0? Mine does to once in a while. But if I switch between presets it will work again. I don't have to shut the computer down. Glad I don't because I have to turn key off (shut engine down) to do that. I only have a on button. 

[Corley5]

Bad wire. Mine would be compromised between the junction block on the boom and the one on the head. Less often between the block on the head and the third wheel. But it could be anywhere. Start checking with a multi meter.

[Firewoodjoe]

A bad wire will work on and off just from moving the machine. Or won't ever start back up again until you fix the wire. Or would even stop measuring while measuring. Mine will measure the full piece every time but when I cut it off re zeroing the computer it won't start back up again. But if I switch from say 0100 to 0120 and back to 0100 it will work fine again. I've heard of lots of glitches. They're old style technology. Mine is a 2005 system with the screen and one box. I'd like to buy the new version. One screen and no boxes. But it's over $5k. I just keep putting it off. 

[Riwaka]

Might do a price check on the feasibility of running the Cypress 6 generation electronics on a Fabtek head. 
Might get the $5K option over the line.

The Making of The Rebel T22HD | New Logging Processor - YouTube

[Firewoodjoe]

Some one out there should have something cheap and simple. I only need to run one encoder and one proximity switch.