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Hydro Ax 670 Cutting Head not working

Started by TFordALA, September 14, 2020, 06:15:04 AM

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TFordALA

 

 I have a 2002 Hydro Ax 670 with a Feller Head on it...Everything works fine on the cutting head but the cutting wheel motor..I have found a switch with 3 wires cut off and they are Red Green And Yellow..The head is a Blount Model # 22BSAWSC and Serial # SA14962..I cannot find any thing on this cutting head to tell me the name of the switch or a wiring diagram..I will insert a picture of machine and switch..its located just behind the cutting head motor with the main feed line running to it..

 

 

 

mike_belben

Praise The Lord

kiko

That plug on the head is the wiring for the saw speed sensor.  Completely unnecessary. The control to turn the saw on is located behind the cab.

 

 

kiko

Correction , that switch in saw head is related to the side cut door. Still not necessary to operate saw disc.

TFordALA

Do I need to jack the cab up to find the control for the saw? Im not to sure on what im looking for.

TFordALA

When I flip the switch to kick on the saw head..it pulls engine way down..I can then click on the hydraulic button and motor evens out. If i click off the hydraulic button it pulls the motor right back down but head wont turn at all.

kiko

The saw solonoid is behind the cab mounted to the support


 
It accessed from the engine cover closet to the cab left hand side. One of the hoses from the solonoid will go directly to the saw pump compensator. The saw pump will be on the bottom of the gear box on the  same side.  The saw circuit and the hydraulic circuit are seperate each with its own pump.  And when I say saw it means only the saw motor that spins the disc. The clamp and accumulator arm work off the hydraulic pump same as the boom and tilt. I don't know the your history with the machine, but it seems some lines are crossed going to the head.

TFordALA

I found that and when I click the switch in the cab..the 1 line going to pump attached to bell housing makes a crazy noise like gears slipping...I hit the hydraulics button inside and the noise stops..the pump and lines get hot real quick as well.

kiko

I don't have a factory diagram so I drew this . I am not an artist.  Is it the saw pump that gets hot . Or is all if them?  The pumps are not actually attached to the flywheel housing but rather the pump drive gear box that is attached to the flywheel housing. I don't think that low oil in the gearbox is your issue but is very important to check oil regularly as that gear box is supper expensive and hard to come by.  Uses 90w gear oil should be a dipstick to check.  It is odd that pilot button makes the noise go away. 


 

TFordALA

Just the pump and lines the control switch is running to..the other pump stays cool but the 1 for the saw will be real hot to the touch and lines as well...

mike_belben

Something is deadheading and going over a relief. 
Praise The Lord

kiko

^^^^^ , the saw works off the setting on the pump compensator but has a main and port relief

 

kiko

Try this one

saw pump is called attachment pump 

mike_belben

I think you have a valve spool on there that is bent, broken or otherwise hung up.  Something seems to be not making a full shift.  


If its open centered the path to tank gets blocked and path to saw motor should simultaneously be revealed but part 2 is not occuring and all flow is forcing the relief open, that is your crazy noise and source of heat.

If its closed centered with a piston pump then i think a swash plate is tilting as it should to turn the pump output flow from no to whoa, but somehow the flow path to saw motor is unavailable.  If you acquired the machine like this or some "mechanic" fooled with something and this was the outcome, suspect incorrect hose routing.  Any other malfunctioning circuits?  Make absolutely certain that the flow has not been routed to a case drain port on the hydraulic motor.  


If it was working and then this change happened on its own, start looking at all valve spools in the saw circuit.  If they are servo controlled figure out what the voltages should be vs what they are.  If its magnetic coils that pull spools, pull the end coils off and check the voltage, resistance and magnetism.  You may have a dead solenoid coil or failing wire that cant carry sufficient amps to generate the necessary volume of magnetic flux to shift the spool over. Look for any [safe] way to manually shift the spool.  Little shifter buttons or holes intentionally there by the manufacturer for a screwdriver or allen wrench to change the spool position for troubleshooting arent uncommon in solenoid hydraulic valves.


If the spool is spring centered/returned, pull the backcap or solenoid endcaps and be sure it isnt a bungled spring, rust ball, frozen detent or dirt dauber nest inside.


If this is a hydraulic pilot control look for leaking in the control pilot side and check pressure, stroke and return of control piston and so forth.


Hope this helps you get some general ideas anyway.
Praise The Lord

kiko

I think figured it out.  There are multiple issues. There is an electrical problem. You should never be able to turn the saw on prior to turning the hydraulics on. There is a malfunction or someone has bypassed some wires. The hydraulic button only turns on the pilot pressure. The spool on the valve is activated with pilot pressure, so if you engage the pump with hydraulics off the valve spool is centered thus the deadhead.  However, the pump is internally regulated piston pump so even if it went against a dead head it should destroke to minimum displacement and not load the engine. The pump could be hung on displacement as Mike said. For now the hydraulics need to be engaged first then the saw on and diagnosis can be done. Gotta get a guage and caps and plugs.

TFordALA

Today we cleaned it up alot so we could see stuff better..the saw pump gets hot within a few seconds of running..Flip the switch and the control switch for the saw pump comes on..Small Hyd line goes from it to the Saw pump and 1 coming from main line feeds the control switch..its vibrates real bad and boggs the engine down..so I can flip the Pilot switch inside and turn on Hyd's..and the control switch for the saw pump cuts off..thus letting engine come back to normal idle. You 2 guys have a real help and thank you both..

mike_belben

Are there any check valves in the saw circuit @kiko ?   Any chance the saw hoses are backward and flow is hitting a directional check?
Praise The Lord

kiko

There is a check valve in the circuit. It is only used to create a loop when the saw is turned off so it can coast to stop, other wise cutting off the saw momentum  would turn the motor into a pump which would have to vent at the port relief. Violent and bad on the motor esp shaft seal.  If this check was stuck open the saw would not work at all because oil sent out of port A would be open to port B.

mike_belben

I gotcha.. So its sorta like a motor spool center to allow the rotor inertia to wind down. 

Well i hope the OP gets it sorted soon and makes some chips. 
Praise The Lord

TFordALA

 
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I need to find the red switch. They have a piece of tape holding it in the "On" position and its for the Hydraulics. Where can I buy this switch and can fix 1 problem easy I hope.  Thanks again..

kiko

The hydraulic switch is made to return. In normal operation hitting this switch one should reset the pilot. Holding it down is just a built in bypass mode.  You need to check your door switches and the door switch relay


 
These relays are located behind the right hand door. Door switches are located at the bottom of each door. 

TFordALA

I have got the head to working by putting a jumper wire on the pilot switch from the Pink Wire to the Yellow Wire..I have cleaned and checked all switches for the doors and they all working.Could the switch be bad and not sending current to the yellow wire somehow? 

kiko

Jumping the wires has done nothing more than bypass the door safety switches, just like holding the switch down with tape.  Under normal operation, the pilot switch would be pressed once and the pilot would lock the door relay. In the event that the door came open during operation the hydraulics would stop.  Have you swapped the door relay with another and have you tried to see what would happen if you unplugged both the door switches ?  

TFordALA

I havnt swapped relays to try that..I unplugged both door switches and tried that..Ill try swapping replays tomorrow and see if that does anything.. No wires are cut and wiring harness seems in good shape..Ill keep trying stuff and putting it on here and hopefully the ideas you passing along will finally find it..thanks for all your help so far..

TFordALA

Swapped out the relays with door and still same thing..have to hold the button down for it to move..I have the jumper wire from the Pink to Yellow wires on the pilot switch and I can click on the button on the dash for the cutter head to come on and everything works way its supposed to..I dont have to hold the pilot button down for it to move..turn that switch off and then you have to hold the button down for it to move...we cant get the pins out to raise the cab so I can   check the wiring under it...this machine has has a rough life.

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