Author Topic: Dewalt 735 switch short  (Read 484 times)

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Offline ear3

  • Posts: 4200
Dewalt 735 switch short
« on: April 07, 2021, 08:14 AM »
Fried my Dewalt 735 last night.  It tripped the fuse on the panel once (in my house, not the breaker on the machine), and then after I reset the breaker, as soon as I engaged the switch on the machine there was the tell tale glow from a short and the machine died. 

Opened it up and found this pretty brutal failure, where it looks like one of the wires split as a result of the short.







I've had to replace the circuit breaker before on the machine, but I've never messed around with the wiring on the switch, so I don't know how this happened -- maybe when I replaced the breaker last year I loosened something that started it down the path towards failure? 

Anyway, was wondering if anyone has ever had this kind of failure before on their 735, and if so what's involved with the fix.  At minimum I would have to get a new motor cord and presumably, also a new switch.  But could there be damage to the motor as well?  I'm not well versed in wiring, and so I don't know the cascade effect these sorts of shorts have on a machine.

It looks like I would actually have to unseat the motor assembly to replace the motor cord, since it runs inside the motor.  Is this something someone like me, who has no intuitive feel for electrical work, and outside of swapping out plug assemblies on my tools, and some very basic wiring of home lighting, has little practical experience with this kind of thing?  There is fortunately a Dewalt service center not too far from me -- the tool is not under warranty, but presumably this is the kind of repair they could handle?

 

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Offline Cheese

  • Posts: 8353
Re: Dewalt 735 switch short
« Reply #1 on: April 07, 2021, 10:11 AM »
Edward, I think I'd look at the motor first, you have what I would consider to be a major meltdown.  [sad]

I've never seen a connector shredded like that before and the black/burn mark at the bulkhead where the wires travel to the motor, also gives me pause. It wouldn't surprise me if you found that there may be some welding of the 3 wires that pass through the bulkhead.

If you own a multimeter I'm sure there are some initial tests you can perform on the motor armature & coils.

Perhaps @Alex has some input on the proper testing procedures.  [smile]
« Last Edit: April 07, 2021, 10:19 AM by Cheese »

Offline Alex

  • Posts: 7349
Re: Dewalt 735 switch short
« Reply #2 on: April 07, 2021, 04:49 PM »
Sorry, I don't really have much useful to offer here. I don't know this tool and I don't know your 110v system.

It seems like a situation of an electrical overload, the wires got too hot, which made them melt and fuse together so Edward got his first fuse tripped. Then with the wires fused together he reset the breaker and started the tool again so now you have a short circuit again, where the current got so high that it melted the wire.

I think it would be best for Edward to let DeWalt sort this out. It is important to find out WHY the overload happened. 

Offline ear3

  • Posts: 4200
Re: Dewalt 735 switch short
« Reply #3 on: April 07, 2021, 06:00 PM »
Thanks guys.  Sounds like this is definitely beyond my skills then.  I'll see if Dewalt can do anything about it.  Unfortunately there's no warranty (got it used 4 years ago), so I would be eating repair.  If it were just the tool it would probably be worth it just to get a new one, but I have the Shelix installed as well.  Presumably the Shelix can be swapped into a new machine -- though I'm not looking forward to the deinstall given how much banging it took to get it into place on the current unit.
« Last Edit: April 07, 2021, 06:16 PM by ear3 »
Kapex KS 120 w/UG Cart and Extensions • CXS Set • T 18+3 w/Centrotec Installer's Set • PDC 18/4 • TID 18 • TS 75 • TSC 55 • HKC 55 w/250, 420 and 670 FSK rails • Carvex 420 w/Accessory Kit • Domino 500 Set • Domino 700 XL • OF 2200 w/Base Accessory Kit • OF 1400 • OF 1010 • MFK 700 EQ Set • LR 32 • MFS 400 w/2000, 1000, and 700 extensions • Rotex 90 • Rotex 150 • LS 130 • ETS-EC 150/5 • ETS-EC 150/3 • Pro 5 LTD • RTS 400 • RAS 115.04 • RS 2 • HL 850 • Vecturo OS 400 • AGC 18-115 • CT 26 w/BT module • CT Sys w/Long-Life Bag • CT-VA 20 • MFT/3 • STM 1800

Offline FestitaMakool

  • Posts: 921
Re: Dewalt 735 switch short
« Reply #4 on: April 07, 2021, 06:17 PM »
I fear the same as Cheese suggests.
If you have an electrician that can measure motors resistance you may well determine if the motor is ok or not, and presume to exchange wiring and switch (to a better one)

Looks familiar?:
I just had my Metabo chip collector give a short mrmm then silent when I tried to switch it on [sad] I’ll do some measuring when I have an electrician who knows motors give me some data to look for (It has a capacitor which may have faulted too)

“The Stig” Yes, it is true, at least some part of it..
“If you have an old Land Rover and a fit wife, you’re most likely always busy”

Offline ear3

  • Posts: 4200
Re: Dewalt 735 switch short
« Reply #5 on: April 07, 2021, 08:11 PM »
That sucks @FakitaMastool I'm sorry.

Speaking of Shelix though, does anyone have any experience DEinstalling the Shelix cutterhead? I assume it's just a matter of reversing the steps,  but I'm curious if there are any bumps along the way.
Kapex KS 120 w/UG Cart and Extensions • CXS Set • T 18+3 w/Centrotec Installer's Set • PDC 18/4 • TID 18 • TS 75 • TSC 55 • HKC 55 w/250, 420 and 670 FSK rails • Carvex 420 w/Accessory Kit • Domino 500 Set • Domino 700 XL • OF 2200 w/Base Accessory Kit • OF 1400 • OF 1010 • MFK 700 EQ Set • LR 32 • MFS 400 w/2000, 1000, and 700 extensions • Rotex 90 • Rotex 150 • LS 130 • ETS-EC 150/5 • ETS-EC 150/3 • Pro 5 LTD • RTS 400 • RAS 115.04 • RS 2 • HL 850 • Vecturo OS 400 • AGC 18-115 • CT 26 w/BT module • CT Sys w/Long-Life Bag • CT-VA 20 • MFT/3 • STM 1800

Offline Banana

  • Posts: 72
Re: Dewalt 735 switch short
« Reply #6 on: April 07, 2021, 08:19 PM »
A casual observation (or a captain obvious observation) just looks like there may have been some abrasion between the load side hot and line side neutral of the DPDT switch from possible vibration.  Though vibration as the cause seems like would have played a minor role.  But because the melting looks like it happened over a long duration I would lean more towards a contaminated crimp from the factory that only became more resistive / hotter over time eventually becoming a resistor and finally melting both jackets of the line hot and load neutral allowing copper in each to touch. 
In between ordering a new switch I would test operation by simply trimming wires way back and wire nutting connections see if motor responds.  I bet it’s fine.  (this is just a temporary test of course).
Any superheated copper wire can turn brassy even at a distance from the original short / burn and is no longer as conductive, but if you cut it back and see nice red copper it’s fine and can be spliced if appropriate or just shortened if it will still reach connection comfortably.

Offline Bob D.

  • Posts: 2008
Re: Dewalt 735 switch short
« Reply #7 on: April 07, 2021, 10:10 PM »
Looking at the photos I was thinking the wires were maybe jammed in there sort of tight and maybe the one that fried was bent hard. I see some smoke on the back panel so that severed wire must have been close to there. Those connectors create a high resistance area especially if they are loose.

Your motor and maybe even the switch are fine, might just need to replace some wiring. Document what you have with a sketch and as many photos as you need to before taking anything apart.

If it's not something you want to tackle just about any place that works on small electrical appliances should be able to rewire this for you. No rocket science involved here.

The switch shows as in stock as the DeWalt parts site.

 Item: #63 - SWITCH
 Part No.: 5140010-63
 Description: SWITCH
 Availability: In Stock
 List Price: $32.08

I think this is the wiring harness, but not sure.

Item: #220 - MOTOR CABLE
Part No.: 5140011-79
Description: MOTOR CABLE
Availability: In Stock - Limited Quantities
List Price: $13.98

https://www.toolservicenet.com/dewalt/en//Dewalt/WOODWORKING/PLANERS//p/DW735_1?documentID=145345
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It's a table saw, do you know where your fingers are?