Drum switch - no forward feed

[WV Sawmiller]

   Used my mill a few minutes yesterday to split a log to make a couple of benches. Cut the legs, mortise and tenon and glued and let the glue dry overnight. This morning I put the benches face down on the mill and set my height to 17" to cut perfectly straight/level legs. Cut about 3' and had to back my mill head up and my forward feed stopped but reverse worked fine. I could move the mill by hand so I finished both benches then checked my WM manual and opened the control panel. I could not find a loose connection or other cause so called WM in Indy. Got Mike on the line and we talked a bit about what I was seeing. I thought a piece had broken off the "axle" of my drum switch but evidently that is the normal shape. Anyway while we talked about the contacts with the fingers I guess I jiggled the right one and everything resumed working as normal. Either the forward finger had slipped or gotten a tiny piece of sawdust under it and I bumped it free.

   Mike gave me a good description of what to look for and how to adjust the contacts periodically as they wear when needed. Was pretty clean in there but I can see it is another area I need to add to my periodic maintenance and maybe keep a can of canned air or small vacuum handy to use there too.

   Anyway everything is back to normal with another lesson learned and a little better understanding of how my mill works and what to look for in the future.

[Magicman]

I hate problems that fix themselves.  They usually have a way of resurfacing at a very inconvenient or inopportune time.   :-\

[Sixacresand]

Had same kind of problem on the LT40 and turned out to be a bad electronic module.  The WM tech on the phone walked me through the diagnostics.   

[Jim_Rogers]

Most mills come with a small tub of lube kept inside the control box to lube the drum switches with.
Did you lube your switch?

Jim Rogers

[WV Sawmiller]

Most mills come with a small tub of lube kept inside the control box to lube the drum switches with.
Did you lube your switch?

Jim Rogers

Jim,

   Mike asked the same question and I did not have a tube in there but discussed using it regularly in the future as part of my maintenance routine.

MM,

   I agree - sort of like an intermittent water leak. If leaks all the time can find and fix it. In this case the problem was fixed when I moved one of the bottom fingers so at least if it shows up again that is where I will start. I'm confident it was a foreign object as it happened instantly and not over time and fixed itself when I moved the right finger/contact. I hope I turn out to be right.

[POSTON WIDEHEAD]

I hate problems that fix themselves.  They usually have a way of resurfacing at a very inconvenient or inopportune time.   :-\

[WV Sawmiller]

I hate problems that fix themselves.  They usually have a way of resurfacing at a very inconvenient or inopportune time.   :-\

MM,

   I think you hoodooed me. Loaded a small ash log on the mill this morning and no forward feed. Opened the cover and it worked. Put cover back on and it didn't work. Opened again, moved the wires over and buttoned it up and it worked. Started the mill and would not work. Opened the panel, it worked, started with the panel open and would not work. At least that was consistent. Finally linked up with Mike again and talked me through a couple more tests and I gave him the results and now he's sending me a new control module. I hope that is all it is as that looks pretty easy to install. We should know Monday.

   In all fairness to WM I did not do a thorough function test yesterday after I got it running again yesterday or we'd have noted these issues then I am sure. I'm just glad it was here at home and not on a distant client site.

[Magicman]

I didn't do it, but hopefully you are now on the right track.   :P

[Cazzhrdwd]

Several times I've had the fingers of the drum switch actually break but stay in place.

[Jim_Rogers]

There was a thread around here somewhere that told how to drill out the finger rivet and replace it with one from another broken switch.
I have never tried that but I figured I would if I had too...

Jim Rogers

[Chuck White]

There was a thread around here somewhere that told how to drill out the finger rivet and replace it with one from another broken switch.
I have never tried that but I figured I would if I had too...

Jim Rogers

Yes, I had a broken up/dn) drum switch finger a couple of years ago, then I had one on the feed drum switch last Summer!

I had to get a new one to replace the up/dn side, but I kept the old one and used a finger off that to fix the feed switch last summer.

Just got to remember that they won't bend very far before they snap off!  Don't bother asking how I know!   :

[WV Sawmiller]

   Its looking likely that the drum switch is not the problem. The black box/controller is the current suspect component. We will see real soon.

[WV Sawmiller]

   Got the new part today as promised by WM and installed it. Only problem other than my fat fingers not liking small screws was all three of the male end spade connectors broken when I tried to disconnect the old part. Must be a trick to uncoupling them I don't know. I had new ones available and put them on and taped good with electric tape to help seal out any moisture. Everything seems to be working properly but I have said that before so I will run a couple of logs through it tomorrow morning just to be sure.

   There are 7 screws that hold the cover in place. Had Phillps head fitting that wanted to slip and booger up the head so I replaced all of them with hex head screws so I can use a nut driver to take them in and out so I can be more diligent about cleaning in there during my regular services.

[Bluejay27]

I had an issue where I would intermittently lose power feed and it turned out to be the positive motor terminal had loosened up and the brush holder wasn't making a good connection. This was on an '08 LT40, the new "current applications" motor looks good, easy to service brushes at least :)

Just as a quick primer on the feed system issues, losing both directions should mean an issue with the motor or wiring, just reverse is always the drum switch, and just forward is either the drum switch or module, although if it lurches forward as the knob is turned, it is likely the potentiometer. Or of course any issue could be mechanical (i.e. bark in the chain).

And the super or better mills buffer the drum switch from the motor current by having it switch on those big solenoids instead, so those can fail while the drum switch looks perfect (no arcing wear).

[barbender]

If I remember right, a bad MOSFET will give you just reverse as well, because the current bypasses the board in reverse.

[WV Sawmiller]

Bluejay,

   That tracks with my issue as reverse worked fine. Just forward did not work under certain conditions (like with the motor running).

Barbender,

   Forgive my ignorance but what is a MOSFET.

Anybody have recommendations on disconnecting the spade connections without breaking them? Since all three broke I suspect technique was an issue and not just a single bad connection.

[Ga Mtn Man]

MOSFET = Metal-Oxide Semiconductor Field-Effect Transistor

In this case we are talking about a circuit board that has several MOSFETS on it, typically referred to as a "MOSFET module".  It is used to switch the current to the motor ON and OFF very rapidly to control the speed of the motor.

In what way did you break the QDT's(spade terminals)?

[Chuck White]

Bluejay,

   That tracks with my issue as reverse worked fine. Just forward did not work under certain conditions (like with the motor running).

Barbender,

   Forgive my ignorance but what is a MOSFET.

Anybody have recommendations on disconnecting the spade connections without breaking them? Since all three broke I suspect technique was an issue and not just a single bad connection.

I took my "feed" drumswitch out yesterday to rebuild the leg (almost worn through on the first finger) that engages the 2 right hand fingers when you return the sawhead to the front of the mill.

Didn't have any trouble with breaking any of the spade lugs, only issue was WHY isn't there an extra inch or so of wire in there so it would be easier to work on the drum switches.

I've been thinking of ways to move both drum switches "outboard", and mount them in a box on top of the operators console!   :P   

[WV Sawmiller]

GMM,

   So I guess the MOSFET is the white connection panel at the top of the panel between and connecting the control module, drum switch and power.

   When I tried to pull the spade connections apart the male end broke back where the wire was crimped onto the spade connection. I had some spares so just cut the wire and crimped a new one on. Only issue was did not have the nice watertight connection under plastic like before so I taped it good with electrical tape when done.

Chuck,

   I had to disconnect the drum to make the connections there. The hard one was the one lug with the 3 half ring red wires. My fat short fingers weren't made for working in such tight spaces.

I took it out for a quick test run using 5 small ash logs. They only yielded about 120 bf of 1X6X8s and a few dozen tomato stakes but the mill had 1.3 hours on it with no more feed problems so I hope that everything is back to normal.

[barbender]

     WV, sorry for the not very detailed comment.  What I was really referring to is the control circuit board, which is known as a PWM (pulse width modulator). This is what allows you to vary the speed of the forward drive (I don't completely understand, but if I remember correctly, by modulating pulse width, you can vary speed without dropping voltage). Power goes through the PWM and on to the feed motor in forward, but in reverse, the power bypasses the PWM because it is not needed, because reverse has a single speed- full speed.  I fried a circuit board, and had reverse but no forward. Hope this helps.

[Chuck White]

That red connection is in a tight/tough enough spot, but then when you add the extra wire it makes it even tougher!

Glad you got it going again!   8)

[Kbeitz]

You can't beat liquid electrical tape for water tight connections.

[POSTON WIDEHEAD]

You can't beat liquid electrical tape for water tight connections.

Where do you buy that?  say_what

[Jim_Rogers]

You can't beat liquid electrical tape for water tight connections.

Where do you buy that?  say_what

From the liquid electrical tape store, where else? ;D

I got mine from Napa I think, but it may have been another auto parts store.

Jim Rogers

[POSTON WIDEHEAD]