Hitachi M12V Owners

[BradTheNailer]

My M12V has a mind of it's own. I pretty sure the variably speed controller is on the blitz but thought I'd check and see if anyone else has had this problem...

Damn thing sounds like a Bee! I $hit you not! It's kinda funny. it's all over the place with RPMs. I know it's equipped with some sort of enhanced speed control so it speeds up a little when you start cutting wood to keep a constant speed, but this dude has lost it's mind.
I don't even have to be cutting wood and it'll go up and down the RPM scale. 14,000 to 20,000 20, to 10, 10 to 15... hell sometimes it just outright STOPS! brushes check out ok. Blew it out with air...cord isn't loose. moving the variable dial doesn't change things.

Was wondering if anyone else has come across this, and what you replaced to fix it?



"you needn't troll the experts ..just come straight to the source" - Limey aka:Robert Bolton

[link:www.mgsawmill.com|M&G Sawmill]. Makers of the finest sawdust in Texas.
Oh, did I mention we have hardwood as well?

http://www.mgsawmill.com/images/flag.gif http://www.mgsawmill.com/images/texas.gif

[stretch2187]

The only time I've had tools do that when the brushes were worn or there was a short in the cord so I'd have to agree that the speed controller might be going out. I'd try to bypass it's wiring and see if that fixed just to try to rule it out.

[Jim_J Lazy 3]

Brad, 1 of my M12V's that's dedicated to a cope cutter in a small router table started the same thing a couple of days ago. Mine seems to be in the variable speed dial. I was in the middle of making some intricate cabinet end frames for a closet system I'm building, and just didn't have the time to really check it out thoroughly, so my "fix" was to wedge a small shim against the dial to keep it one place, so's I could finish and get on with the rest of the project.
I suspect a new variable speed is in order, or, bypass that and run a direct drive single (fast) speed. Let me know what you discover. ..........Jim@JLazy3

"The only thing certain in life ...is uncertainty!"

[arcticfox46]

Mine has not given me any trouble yet, but I expect it to do the same thing some day. That is one of the things I saw in the reviews when I bought it.

I am just waiting for the excuse to get the Porter Cable 7518 into the router table, and do a couple of table upgrades.

Of course I will get the M12V fixed in that day and have it as another router.

[niki]

Go to this site and click on the "Parts List" and down load it. it's a small PDF file.
http://www.hitachipowertools.ca/en/Products?cat=46&pid=108

Remove the back cover and slowly remove item # 3 it's a computer chip ("controller circuit") that controls the speed.

You don't have to disconnect it from the wires, just lift it up to reveal what's under

Now, look at Item # 4...it's a magnet that rotates with the motor shaft...it's actually a speed sensor that has an inside thread that screws over the motor shaft.
It's an aluminum hex with a round magnet on top.
If this part is loose the "controller circuit" does not know what is the motor speed and the speed goes up and down.

I had the same on my M8V, I called Hitachi (Japan) and they sent me 2 of them.
In my case, the thread inside the "magnet" was totally worn-out . I changed it and everything is ok now.

I would suggest that when you tight the "magnet" on the motor shaft, use some kind of locking liquid or past to prevent it from getting loose again.

Regards
niki

[BradTheNailer]

Thanks for the help.

I tried all the suggestions, none worked. I'm guessing the controller is the problem. $111 for a new one. Looks like I'll be bypassing the controller and adding a speed controller from HF. That's ashame, such a work horse of a router yet the electronics are junk (as usual).



"you needn't troll the experts ..just come straight to the source" - Limey aka:Robert Bolton

[link:www.mgsawmill.com|M&G Sawmill]. Makers of the finest sawdust in Texas.
Oh, did I mention we have hardwood as well?

http://www.mgsawmill.com/images/flag.gif http://www.mgsawmill.com/images/texas.gif