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DeWalt 733 planer died today

10K views 46 replies 14 participants last post by  JFPNCM 
#1 ·
I bought it new in 1997 and used it off and on for the first 17 years but in the last 3 I have used it a lot, sometimes daily. It has always run fine but today I turned it on and it ran for 1/2 a second then quit. Here's what I know:

1) It is getting power, I even switched to different circuit altogether
2) I pulled the switch out to verify that it is good
3) The brushes, though original, are still 1/2" long and show no signs of chipping or abnormal wear
4) The wires on the brushes are intact and the springs have plenty of tension
5) The motor is easy to spins (took the side covers off to verify)
6) The 18 amp built-in breaker on the top of the motor is in the position it should be in
7) In shining a light onto the commutator I see no chips or bridged arcs between segments

I don't really want to spend the money on a new planer and would rather get this one running again. I can order new brushes just to rule that out but again, the current ones look fine to me.

Ideas?

David
 
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#6 ·
do that to the breaker too...
 
#3 ·
With me it was a drill press. Replaced the switch and that was all it took to fix it. Still going strong.
 
#4 ·
That's what I don't understand. It has never given a hint of trouble and ran fine yesterday. When I turned it on today and it ran for a 1/2 second I thought it must have tripped a breaker. But everything else plugged into that same circuit runs fine. So I plugged it into another one with the same result. Then I pulled the switch completely out, plugged it in again, and checked power on both sides of the switch and there's a full 120 volts on the motor side of the switch.

This is the position of the breaker switch, looks to me like that's where it's supposed to be. And it doesn't want to move at all other than a slight rocking back and forth but it's always been like that. And it has never tripped.

Yellow Vehicle Bumper Automotive exterior Hood


Yellow Technology Electronics Electronic device


David
 
#8 ·
That's what I don't understand. It has never given a hint of trouble and ran fine yesterday. When I turned it on today and it ran for a 1/2 second I thought it must have tripped a breaker. But everything else plugged into that same circuit runs fine. So I plugged it into another one with the same result. Then I pulled the switch completely out, plugged it in again, and checked power on both sides of the switch and there's a full 120 volts on the motor side of the switch.

This is the position of the breaker switch, looks to me like that's where it's supposed to be. And it doesn't want to move at all other than a slight rocking back and forth but it's always been like that. And it has never tripped.

View attachment 300066

View attachment 300074

David
I would get to the switch, detach some wire(s) and check the switch continuity when in ON & OFF positions...

Do the same thing to the Breaker / Fuse IN THE Machine... The Breaker could go bad... and if the breaker went bad, there is probably a REASON for it... ergo, another problem somewhere... (??)

Those two items should shed some light on it...
You have to check each one on it's own, NOT connected to the machine.

Let us know what happens, OK?

Good luck...
 
#5 ·
Jumpering a wire across the breaker contacts will prove if that's the problem at least. Just do that and turn it on. Be prepared to turn it off quickly too. It doesn't sound like a burned armature and you say it shows no signs. Usually there is a drop in power and rpm just before it quits if that is the problem. About the only other thing I can think of is a broken wire.
 
#11 ·
I'll have to do a complete breakdown to get to the wires past the switch, Tom. I can see about 3" of wire and that's all. It's getting power, tried two sources. The blades spin easily by hand, no resistance above what it should be with the drive belt still attached.

Thanks!
David
 
#14 ·
I thought about that but not being certain I didn't want to break it. I may dive into the motor breakdown PDF and see if I can tell. If so that would be MUCH easier! Thanks!

You did check the brushes, right? DeWalt brushes only last about 100 hours on their handheld tools.
I thought about that, too, but when I talked to DeWalt they told me the OEM replacement brush is only a tiny bit longer than mine at 1/2". The manual says there's a line on the brush and when that line is reached it's time to change them. This model doesn't have the line but when I look at a photo of the replacement brush that line is about 1/8" from the spring. If that's the case then these are lifetime brushes, for me, anyway. Thanks!

David
 
#15 ·
Thing that gets my attention David, is that it started then stopped. I'm assuming you hadn't actually started running a board through when it quit?
It really sounds like there's a break in the cct. somewhere(?). As others have said, if it were a motor issue you should have had some kind of indication before it died.
You're getting power on the load side of the switch so that (probably) eliminates everything between the load side of that switch and the panel.
Are there any safety interlocks of any kind, other than the breaker?
 
#18 ·
Correct, Dan, it didn't run long enough to even get my hand off the switch so no boards went through. I don't see any interlocks other than the 18 amp built-in breaker (overload).

Did the motor 'wind down" when it quite or did it suddenly STOP?
No, Bill, it spun down but never even got up to half speed. Well, maybe a better way to say that is it wound down from whatever speed it attained in that 1/2 second, which may have been more like 1/4 second. And the motor is very free to spin by hand.

Thanks, Guys!
David
 
#20 ·
switch/cable/brushes sound good. Doubt that the breaker is at fault, since its never tripped before...sounds to me like a wire come loose/broke at the motor...thats where I'd be heading
 
#26 ·
I can measure voltage to the motor side of the switch so something is open between the switch and the motor (brushes).

I got to thinking that maybe I can see the breaker through the switch opening if I remove the switch and I can see it just fine, no disassembly necessary. And the good thing is that the breaker is closed so I can rule that out. I still don't really have time to break the unit down to get the motor out so that may have to wait.

Yellow


David
 
#27 ·
I can measure voltage to the motor side of the switch so something is open between the switch and the motor (brushes).

I got to thinking that maybe I can see the breaker through the switch opening if I remove the switch and I can see it just fine, no disassembly necessary. And the good thing is that the breaker is closed so I can rule that out. I still don't really have time to break the unit down to get the motor out so that may have to wait.

View attachment 300162

David
OK, it sounds like you have voltage coming OUT of the switch... BUT cannot measure voltage AT the motor... which is the key question... You MUST be able to measure voltage AT the Motor...
 
#28 ·
I took the time to take the motor off after I figured out that I didn't have to disassemble the entire unit (makes sense that it would come off without that...).

So here's what I have:
1) The two white leads in the photo are open and show no value.
2) There is no short or value between either lead and the commutator.
3) I went through the brush openings and checked resistance across the commutator segments 180° apart and all read the same.
4) It appears that going much further in this disassembly may require special tools, puller, etc. I can get the gearbox off but that's not going to do much for me at this point.

David

Machine Construction equipment Wire Vehicle
 
#29 ·
I took the time to take the motor off after I figured out that I didn't have to disassemble the entire unit (makes sense that it would come off without that...).

So here's what I have:
1) The two white leads in the photo are open and show no value.
2) There is no short or value between either lead and the commutator.
3) I went through the brush openings and checked resistance across the commutator segments 180° apart and all read the same.
4) It appears that going much further in this disassembly may require special tools, puller, etc. I can get the gearbox off but that's not going to do much for me at this point.

David

View attachment 300290
If those are the ONLY two wires coming from the motor... and there is NO continuity between them, to me, that indicates the circuit is OPEN where if voltage were applied, NOTHING would happen... ergo, Bad Motor.

It's nice that it should not be too hard to replace it!

Also looks like a lot of carbon around everything, etc.

You would have nothing to lose by taking the motor apart (so you could put back together) looking for disconnected wires, etc. (which could easily be fixed with a little solder, etc.)

Are the Motors still available? At what cost?

I think you really Found the problem... Finally! :)

Good Luck!
 
#35 ·
Well, I thought I was through with this topic but when I saw the blades I had to post a photo. I have not sharpened or replaced blades in the entire 20 years I've had this planer. This is the first time I've even seen them except to take a glance from the working side on occasion.

Not too bad after 20 years -
Bumper Automotive exterior Machine


David
 
#36 ·
Well, I thought I was through with this topic but when I saw the blades I had to post a photo. I have not sharpened or replaced blades in the entire 20 years I've had this planer. This is the first time I've even seen them except to take a glance from the working side on occasion.

Not too bad after 20 years -
View attachment 300370

David
... maybe they put an extra Drag on the motor... (?) :) :D
 
#39 ·
Hi Guys, I have had a similar problem. Motor was not running good so
I replaced the brushes(old ones were worn out after inspecting them) and when
I hit the power switch nothing!!! Power switch was good as well as the breaker.
The last thing I did was(with the power off of course) spin the motor a bit by pulling
on the belt(did not have to take the case off as you can find a small opening that will
let a couple of fingers in to advance the motor by pulling on the belt).

MUCH TO MY SURPRISE BAM!!!! I pulled the switch She is up and running again.

After all that it was a 5 second fix...LOL!
 
#42 ·
Welcome to the forum, Will! There's no way I could have done that with mine. 'Cause if I had done that I wouldn't have ended up with a veneer press and a new DeWalt 735! :no: :laugh:

David
 
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