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Woodworking Discussion Forum
lacks focus
Member since Jan-22-07
810 posts |
Apr-11-09, 03:39 PM (EST) |
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"table saw troubleshooting"
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I could use some troubleshooting advice for my table saw. I was in the middle of making a number of small cuts this afternoon, and apparently I turned the saw on and off one too many times. Now it won't turn on at all. There were no odd noises or smells or anything the last time it was on. The motor hasn't seized up - you can turn it by hand easily and smoothly. The circuit breaker hasn't tripped - in fact it's on the same circuit as some of the shop lights and they're all on. The breaker on the motor hasn't tripped, either - the little reset button hasn't popped out, so it doesn't need to be reset. The switch itself now feels a little funny, like it's got a minor hitch in its gitalong (as Andy Griffith used to say). I've disassembled the switch plate assembly to the point where it's obvious there are no loose plug-in/crimp-on connections inside it, though the innards of the actual little switchbox with the terminals on it remain invisible to me - I think I'd have to break it to get it apart (part no.72 in the attached pic). Before I do that, or try to order a replacement, does anyone have any further troubleshooting suggestions to try to make sure the switch is where the problem is? I'm blanking on other things to try. BTW, this is Delta's entry level contractor saw, model 36-978. Craig in Indy "Ubi amici, ibi opes" - Where there are friends, there is wealth. |
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Sawduster
Member since Sep-2-04
15642 posts |
Apr-11-09, 04:21 PM (EST) |
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2. "RE: table saw troubleshooting"
In response to message #0
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I'd say chances are very good that the switch has gone south, but you can check that out by bypassing the switch in the circuit using a jumper. If you've got a multi-meter or even one of those little circuit testing lights, you could check for power in the wires at the motor with the switch in the on position or simply check continuity of the switch itself. If the switch has a different "feel" to it when you flip it, then that's another sign it has gone bad. Jerry 
A "Charter Member" before the crash of '04.
"If politics wasn't built on careful deception it wouldn't need its own word and techniques. It would just be called honesty, education, and leadership."
Bob "Phydeaux" Stewart one day on Woodnet Visit my woodworking website:
http://www.sawdustersplace.com
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TDHofstetter
Charter Member
17010 posts |
Apr-11-09, 05:02 PM (EST) |
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3. "RE: table saw troubleshooting"
In response to message #0
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#77 leads to the motor, true? And... from the power cord there are three wires - green, white, and black? And in the cord leading to the motor there are also three wires - green, white, and black? And... the greens connect to each other and also connect to the machine's iron someplace? They're ground wires. Protective. No other purpose. And... the white connect to each other but to nothing else? And... the black wires duck into the switch? Both of 'em? And... the back of the switch has two connectors on it, and the wires plug onto those connectors with what's commonly known as "quick disconnects"? Shaped like a little flat fist that wraps around a blade on the back of the switch? Cool. Thought so.  So... leave all the wiring alone except for those two black wires with their quick-disconnects (QDs). UNPLUG THE HECK OUT OF THE SAW. Now unplug those two QD connectors. It won't ever matter which terminal they go to, but it can't hurt to remember which went to which. Fit one QD onto the other QD, so the two black wires are connected together. If they won't go because they're covered with rigid insulation, go find a little short length of some sorta' wire that'll fit into both of 'em. A paper clip will probably do just fine. Now... don't let those suckers touch any metal on the saw or anywhere else in the shop. Just kinda' prop 'em away from everything. Cardboard shield if they wanta' spring back & touch something. Ready? Plug the saw in. You've just wired past the switch, so it'll start the instant you plug it in (if the switch is bad). That's what I expect. If it does start & run when you plug it in... then you've ruled out everything except the switch. Unplug the saw again & plug the two black wires back into the switch. We're going to verify, just in case something ELSE was the problem & self-fixed. Switch off, plug the saw in. It won't run. Try to switch the saw on. If it doesn't work, then the switch is definitely your gremlin. Replace it & leave a check on the counter. -- Tim -- Member of the
Robert "Limey" Bolton Memorial
International
Volunteer Mentorship and Assistance
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lacks focus
Member since Jan-22-07
810 posts |
Apr-11-09, 06:12 PM (EST) |
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4. "RE: table saw troubleshooting"
In response to message #3
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>#77 leads to the motor, true? Yes. >from the power cord there are three wires - green, white, and black? And in the
>cord leading to the motor there are also three wires - green, white, and black? Yes. >And... the greens connect to each other and also connect to
>the machine's iron someplace? Sort of. They don't actually connect directly to each other, but they both connect to the metal plate that attaches the switch assembly to the frame of the saw. >And... the white connect to each other but to nothing else? Not quite - both sets of blacks and whites are wired to female "quick disconnects" that are plugged onto the male prongs/blades/spades on the body of the switch. See the attached pic I took of the switch assembly's guts. The wires on the right go to the motor, and the ones on the left go to the AC plug. Given all of that, should I jump only the blacks as you suggest, or is my assumption that I need to jump both blacks and whites correct? Your check's in the mail, BTW.  Craig in Indy "Ubi amici, ibi opes" - Where there are friends, there is wealth. |
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TDHofstetter
Charter Member
17010 posts |
Apr-11-09, 06:20 PM (EST) |
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5. "RE: table saw troubleshooting"
In response to message #4
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Aha. That saw's set up so it can be run on either 120V or 240V without changing the switch wiring. Good - very good. Since it's that way, jump the blacks to each other, and also jump the whites to each other. Now... if the saw's running on 240V (I think it is), and if ya got lucky & only one half of the switch has gone away on ya... you can still use the half that's working for the interim, while you wait for the replacement. The trick will be finding which half (if either) is still working. In such a case, you'd leave the white wires connected to each other and only switch the black ones. -- Tim -- Member of the
Robert "Limey" Bolton Memorial
International
Volunteer Mentorship and Assistance
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lacks focus
Member since Jan-22-07
810 posts |
Apr-11-09, 06:39 PM (EST) |
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6. "RE: table saw troubleshooting"
In response to message #5
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That did it, Tim. When I jumped the black-to-black and white-to-white, and then plugged it in, the saw came to life. I unplugged it (quickly - no point in having glowing-hot paper clips), reconnected the switch, plugged the saw in and switched it to "on" and nothing happened. No self-healing going on in this house. Guess I'll be ordering $20 worth of a new #72. Thanks for the help! Craig in Indy "Ubi amici, ibi opes" - Where there are friends, there is wealth. |
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rrich
Member since Sep-3-04
9002 posts |
Apr-11-09, 08:59 PM (EST) |
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7. "RE: table saw troubleshooting"
In response to message #6
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If you're running on 120 volts try this. Connect the two whites together and tape them up to insulate the connection. First try the switch to turn the saw on. If this works, close everything up and continue making sawdust. If the saw still won't turn on, move the black wires to where the white wires were previously connected. The saw should work then. BTW - Usually when the capacitors fail, they bulge and it is quite obvious. The tops and bottoms are usually domed and should be flat. All,
As Tim noted, most saws come with a double pole switch. (i.e. Two separate circuits or paths through the switch.) Because 120 volt service only needs a switch in the hot (Black) wire this quick fix will work. Craig, I would still order a new switch so that it is on hand if the quick fix eventually fails.
Rich
Huntington Beach, CA USA Help! I've dropped my nail gun and can't glue up. |
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