# Harbor Frieght 10" miter saw stopped turning on



## timcsi (Jun 10, 2009)

hello,

Harbor Frieght 10" miter saw stopped turning on. I've checked and the brushes look fine. Several videos mentioned to check for "continuity" on the switch and I'm not very clear on how to test it. See below multimeter screenshot - do I set it to that setting to test continuity ?









Below is the switch screenshot. On the switch where exactly should I touch with the red/black leads ? where the black/white wires are ? Not clear on this....


How do I test the continuity ? I assume there should be no power to the saw and then I depress the switch to see if the resistance goes down to zero ? Is that how to tell a bad switch ?

Some vides mentioned a lose wire inside the motor housing. On this saw i'm having a hard time pulling off the red motor housing so I can inspect the inside. I have taken out the 4 screws as below and the red housing is loose and I can wiggle it. But something is locking up the housing and I'm able to pull it out. I tried depressing the blade lock but still couldn't pull it out :









What else to check ?

Thanks !


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## timcsi (Jun 10, 2009)

Here is the switch screenshot photo. The page keeps saying "thumbnail uploading, refresh page to view" but the photo is so small. So re-posting here :


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## DexterII (Jul 14, 2010)

First, yes, power off, unplugged when checking continuity. At the switch, I assume the black wire and the white wire next to it both come from the plug? Then no, you should not have continuity between them, but with the switch depressed you should have continuity between each of them and the wires directly across from them. As far as the red housing, I believe that you would first have to remove the brushes, and those are what's preventing it from sliding off. And reinstalling the brushes can be a bit challenging sometimes so if you do end up removing them pay attention to the process in order to reverse it when it goes back together. I'd be more inclined to suspect the switch though, in which case there is no need to remove that housing.


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## Half-fast eddie (Sep 19, 2020)

If you put the meter on those 2 terminal with the saw plugged in, you should be measuring 120v. Have you tried removing the black plug to get to the brushes?


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## mark_kershner (Mar 11, 2017)

Look on the switch covered by the yellow trigger. There may be a diagram indicating connections for the switch. The terminals should be marked accordingly. Here’s a recap of a solution that has worked for others. Read the reviews related to the ebay listing. Good luck. 


“98199 Miter Saw 10" by Chicago Electric Harbor Freight Tools damaged Trigger Switch (part 116 on diagram).
Needed to replace JIABEN FA1-10/2 or DA1-10/2W trigger switch, which is 10A rated switch with one Normally Closed contact and one Normally Opened contact.
Can't find exact model from JIABEN on the web.
Instead bought on EBAY 'Aftermarket Trigger Switch Eaton Style Overhang rep Dewalt 153609-00 1/pk SW38D' from 'toolmart750' user for about $10 with free shipping.

Actually its even better part since it rated 12A instead of original 10A rating.

Or similar can be bought for about $10 on Amazon 'Superior Electric SW38A Aftermarket Trigger Switch (Eaton Style) Large Button 24/12A 125/250V:”

Link. Aftermarket Trigger Switch Eaton Style Overhang rep Dewalt 153609-00 1/pk SW38D


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## timcsi (Jun 10, 2009)

Took apart the plastic handle so I can take a detailed photo. There are 3 wires from power cord :
1. black wire goes into the motor housing instead of the switch and there's another black wire coming out of motor housing that connects to the switch
2. white connects directly to the switch
3. ground wire
There are also two unknown white wires coming out of motor housing that connect to the switch. Please see below photo :









I'm not clear - How exactly do I test the switch ? (where to touch the red/black dial on my multimeter). Do I connect power to the saw ? Am I testing continuity or 120v(what setting to test this) ? Is this the multimeter setting I should use ? I have the Centech multimeter as shown below :









The black plug and the brushes have been removed, I still couldn't pulled apart the red motor housing :










Thank you


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## DexterII (Jul 14, 2010)

No power to the saw. Unplug it. Yes, the dial on the meter is fine where it's at. When checking continuity you are reading ohms, which is denoted by the omega symbol. Not sure if the picture of the meter is from the web or you chopped it yourself, but pretty sure there is another hole for the leads, and you want the leads in the bottom two holes. With the leads in those holes and the dial on the meter in that position, touch the leads together and the meter should indicate continuity. Now, on the switch, touch one lead to the terminal on the switch with the black wire and the other lead to the terminal directly across the long way from it. Then do the same thing with the terminals next to those. If the switch is good, I believe that on both sets of terminals you will have no continuity with the switch in the open position, and continuity with the switch closed, or depressed.


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## mark_kershner (Mar 11, 2017)

The switch maybe one NO and one NC as letting off the trigger indices braking. OP needs to see either a diagram on the switch or dissect it. 


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## DexterII (Jul 14, 2010)

Yup, good point. I was in bit of a hurry to get some boards cut and make sure everything was going to fit the way I wanted but kept thinking there might be more to it than what I indicated and that's it. So yes, OP, you're going to want to know what is supposed to be open or closed and when, and a schematic is the best place to start.


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## Mordekyle (Dec 3, 2020)

timcsi said:


> hello,
> 
> Harbor Frieght 10" miter saw stopped turning on.. . .
> 
> ...


Craigslist. 

Used miter saws are cheap.

Never buy electric or electronic items from HF.

Buy once, cry once.


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## Half-fast eddie (Sep 19, 2020)

Mordekyle said:


> Never buy electric or electronic items from HF.


Disagree. HF tools certainly have their place, if you recognize the limitations they can be very good starter tools.


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## timcsi (Jun 10, 2009)

DexterII said:


> ......... With the leads in those holes and the dial on the meter in that position, touch the leads together and the meter should indicate continuity. Now, on the switch, touch one lead to the terminal on the switch with the black wire and the other lead to the terminal directly across the long way from it. Then do the same thing with the terminals next to those. If the switch is good, I believe that on both sets of terminals you will have no continuity with the switch in the open position, and continuity with the switch closed, or depressed.


Yes I put multimeter in this position and touched black/red leads and it went from "1" to some numbers so I assume the continuity test is working. Here's a view of my multimeter :










Do you mean to do below Test #1 and Test #2 with and without depressing the switch ?









Some more views of the switch. It has some diagram indicating 1,2,3,4 - I assume some sort of circuit diagram but not sure what it means :

















Thanks guys


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## HuckPie (Nov 15, 2020)

Did you try hitting the handle with a
rubber mallet while pulling on the trigger?
That would have been the first thing I tried.


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## mark_kershner (Mar 11, 2017)

You are on the right track. If I read the diagram on the switch correctly, The switch will have numbers (1, 2, 3, and 4) by each wire. Without pulling trigger, check continuity between 2 & 4. Should read similar to the number you get when you touch the meter leads together. Now check 1 & 3. The meter should not change. Now, while keeping the leads on 1 & 3, pull the trigger. Number should change to the number you get with leads touching. With trigger still pulled, check 2 & 4. Number should be the number you see when leads don’t touch anything. 


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## DexterII (Jul 14, 2010)

Might be, and markings on switches can sometime be less than clear, particularly those made on the other side of the Pacific, so hard to say for sure without a schematic for the saw, but I suspect that 1 & 3 and 2 & 4 should have no continuity regardless of whether the switch is open or closed, and that 1 & 2 and 3 & 4 should read open, or no continuity when the switch is released and should read closed, or full continuity when the switch is depressed.


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## mark_kershner (Mar 11, 2017)

The OP contact sketch is not correct from what I can see from the diagram on the switch. It is missing the contact bridges. 


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## timcsi (Jun 10, 2009)

Better view of the switch circuit diagram :











mark_kershner said:


> You are on the right track. If I read the diagram on the switch correctly, The switch will have numbers (1, 2, 3, and 4) by each wire. Without pulling trigger, check continuity between 2 & 4. Should read similar to the number you get when you touch the meter leads together. Now check 1 & 3. The meter should not change. Now, while keeping the leads on 1 & 3, pull the trigger. Number should change to the number you get with leads touching. With trigger still pulled, check 2 & 4. Number should be the number you see when leads don’t touch anything.


I did the following tests according to your instructions. 

First of all, showing multimeter leads not touching, shows "1" :









Multimeter leads touching shows "0.01" :










Now touch 1 and 3 on the switch :

without pressing switch shows "1" - same as multimeter leads not touching
with switch pressed nothing happened, still shows "1"











Touch 2 and 4 :

without pressing switch shows "0.01" - same value as multimeter leads touching each other
with switch pressed nothing happened, still shows "0.01"










Basically pressing switch is not changing anything in any case. Does that indicate the problem of this saw not starting is due to a broken switch ?


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## mark_kershner (Mar 11, 2017)

The switch is bad. Check a previous reply to get a link to a switch others have used from ebay. You will need to make minor changes to the the area where the switch fits to install the switch. I have not found a source for the direct replacement switch. Good luck. Sounds like you are on the way to a working saw. Wire the new switch so existing 1-3 is open (1 on meter) and 2-4 is closed (0.01 on meter) with trigger not pulled. 


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## timcsi (Jun 10, 2009)

mark_kershner said:


> The switch is bad. Check a previous reply to get a link to a switch others have used from ebay. You will need to make minor changes to the the area where the switch fits to install the switch. I have not found a source for the direct replacement switch. Good luck. Sounds like you are on the way to a working saw. Wire the new switch so existing 1-3 is open (1 on meter) and 2-4 is closed (0.01 on meter) with trigger not pulled.
> 
> 
> Sent from my iPhone using Tapatalk


Thanks so much !


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## Mordekyle (Dec 3, 2020)

Half-fast eddie said:


> Disagree. HF tools certainly have their place, if you recognize the limitations they can be very good starter tools.


$150 for a used Dewalt is pretty common. We wouldn’t have this thread.


HF tools do have their place, that’s for sure.


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## timcsi (Jun 10, 2009)

mark_kershner said:


> The switch is bad. Check a previous reply to get a link to a switch others have used from ebay. You will need to make minor changes to the the area where the switch fits to install the switch. I have not found a source for the direct replacement switch. Good luck. Sounds like you are on the way to a working saw. Wire the new switch so existing 1-3 is open (1 on meter) and 2-4 is closed (0.01 on meter) with trigger not pulled.


Just received "Superior Electric SW38A Aftermarket Trigger Switch (Eaton Style) Large Button 24/12A 125/250V" from Amazon. Not sure how to connect the wires to this switch. Below is the switch and its circuit diagram. It doesn't have 1,2,3,4 instead it has 1,1,2,2

I can see from circuit diagram that 1-1 are open circuit(Checked with multimeter showing 1) , so are 2-2. If I press trigger and check multimeter on 1-1 it goes to 0.00. Same with 2-2. So that's good I assume. But how do I wire the original 1,2,3,4 to this new switch ?
Thanks


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## mark_kershner (Mar 11, 2017)

The switch you received is not what is advertised on Amazon. You need a switch that has one No and one NC contact as shown on Amazon










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## timcsi (Jun 10, 2009)

I see it's the wrong one, learn something new everyday
Thanks


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## ratherbefishing (Jan 13, 2011)

I'm thinking the NC contact is for the brake. Is my reasoning correct?


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## mark_kershner (Mar 11, 2017)

Yes. That is my opinion as well. The saw could run without the NC set but it would allow the blade to spin way too long after letting go of the trigger. 


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## timcsi (Jun 10, 2009)

Thanks ! Today I finally got the correct switch and I wired the original 1-3 wires to the 1-1(NO) then 2-4 wires to 2-2(NC) and the saw turns back on !

The correct switch is "Superior Electric SW38D Aftermarket Trigger Switch Eaton Style Overhang Trigger REPLACES Dewalt 153609-00" :
Amazon.com: Superior Electric SW38D Aftermarket Trigger Switch Eaton Style Overhang Trigger REPLACES Dewalt 153609-00: Home Improvement

There are many reviewers In the Amazon comment sections talking about it working for Harbor Frieght saw.

BTW you are right, the other wrong switch will still work but there is no braking.


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## ratherbefishing (Jan 13, 2011)

Thanks for "closing the loop" with an update.


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