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woodmizer forward control trouble

Started by sandmar, May 27, 2008, 10:05:39 PM

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sandmar

Hey, I figured some of you might have had this problem also. 2004 LT 40 HD-Forward speed control acting up. The  idiot lights on the control board in the back of control case keeps showing OV-over voltage. The only high voltge I can find is on the square silver box on the other end.......don't ask me what it is.....I almost had to call it a doohickey  ;D It shows about 18 volts on its terminals,everywhere else I get about 14.5volts. It the doo hickey my problem? and what is it really? Thanks for your help!

sandmar

MartyParsons

The Voltage seems HIGH. What is the Alternator putting out? should be 13.8 to 14.2. Volts DC. I am assuming the power feed is not working at all?
Marty
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

MartyParsons

There is a good trouble shooting information in the operators manual. The aluminum doohicky is a Mosfet module or solenoid with no moving parts works on the ground circuit. There is also anothe doohicky that has only one wire and a diode in the center.
M
"A pessimist sees difficulty in every opportunity; an optimist sees opportunity in every difficulty." -Winston Churchill

sandmar

Hi Marty,the aluminum square with the diode in the center is where I get the 16-18 volt readings.Everywhere else seems to be around 14-14.5 volts. Is this box my problem? Is diode bad and needing to be replaced? Thanks for your time.

sandmar

Just so you know: per woodmizer: replace whole new back panel to the tune of $314  :o
what caused this problem?: per woodmizer: they just burn up,new panel has resistor to help prevent this ::)
My mill was bought in march 04 and has 187 hours on it, and is stored in barn,did anyone else go through this?

sparks

The overvolt condition is caused by the voltage from the power feed motor. The voltage it is seeing is a kick back voltage from the motor not the alternator. Most likely the suppresor failed which cause the free wheeling diode to allow to much to kick back to the board which in turn can fry the mosfet. We have added an additional suppressor on the power feed module to block these spikes to protect the board better.
The spikes are usually caused by the motor working harder to move the head back and forth. Definitly check the rollers the head rides on as well as the chain sprocket and roller. Spin them with your fingers and if you feel any roughnes or tighness replace the rollers. We see this more on mills that sit alot and are not used often. The grease in the rollers have a tendency to drain to the bottom side of the roller and the exposed inner bearing rollers can begin to rust. As the mill gets used again it takes quite a few passes to get this grease spread around the internal parts causing the motor to really work harder.
It's a long explaination but I hope it helps. It is worse on the mill to sit than it is to run it every day.    Thanks all and be careful out there.
\"America will never be destroyed from the outside. If we falter and lose our freedoms, it will be because we destroyed ourselves.\" Abraham Lincoln

Bibbyman

Quote from: sparks on May 28, 2008, 04:53:28 PM
The overvolt condition is caused by the voltage from the power feed motor. The voltage it is seeing is a kick back voltage from the motor not the alternator. Most likely the suppresor failed which cause the free wheeling diode to allow to much to kick back to the board which in turn can fry the mosfet. We have added an additional suppressor on the power feed module to block these spikes to protect the board better.
The spikes are usually caused by the motor working harder to move the head back and forth. Definitly check the rollers the head rides on as well as the chain sprocket and roller. Spin them with your fingers and if you feel any roughnes or tighness replace the rollers. We see this more on mills that sit alot and are not used often. The grease in the rollers have a tendency to drain to the bottom side of the roller and the exposed inner bearing rollers can begin to rust. As the mill gets used again it takes quite a few passes to get this grease spread around the internal parts causing the motor to really work harder.
It's a long explaination but I hope it helps. It is worse on the mill to sit than it is to run it every day.    Thanks all and be careful out there.

That's the conclusion I came to also.  Just Sparks tells it much better. 

Well, not really.  That's why he's in there telling people how to fix them and I'm out here breaking things. ;D
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

sandmar

Thanks sparks and bibbyman! 8) Those are the answers I was looking for! I know I sound like a noob calling things a doohickey,but a proper explanation goes a the comfort zone. Being told they just burn out,gave me a real uneasy feeling  :-\ I knew I could count on this forum to set things straight....THANKS GUYS! ;)

sandmar

New control board installed,mill purring like a kitten..................making sawdust again  8)

Thanks to everyone again!  ;)

78NHTFY

Hello Sandmar
Had same problem & your post showed me how to solve it--thks.  Guys @ Woodmizer walked me thru & my LT 40 manual now has fwd!  So far, at 300 hrs, that's been the only real problem.  Time to make some sawdust, again....
If you have time, you win....

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