My Excalibur EX-21 Has Stopped

[BadBob]

The motor turns freely. So it isn't bearings or brushes. There is not much left.

 

 

[BadBob]

Grand Total $296.47 for Controller Board and Motor.

 

 

Edited November 6, 2022 by BadBob

[Scrappile]

Just a Thought.  While you got that meter handy, did you do a check of your on/off switch?  I know you said you blew it out, but it could really be bad, not just durty.

[BadBob]

20 hours ago, Scrappile said:

Just a Thought.  While you got that meter handy, did you do a check of your on/off switch?  I know you said you blew it out, but it could really be bad, not just durty.

The switch works fine. Since I was measuring the output of the controller card with the switch in the circuit and I have DC volts, the switch is OK.

[BadBob]

I think one is DC ground, and the other is AC ground.

[BadBob]

My EX-21 Controller Board.

 

[BadBob]

What the saw looks like now.

[BadBob]

I did some testing using a 2.5 HP DC treadmill motor. You can run it off of a car battery, a car battery charger, and a 20V DeWalt Lithium battery. A 9V Alcaline battery also works. My DC bench power supply did not work and was overloaded immediately.

I pulled the scrollsaw motor and connected it to a battery with it on the bench. Nothing happened, so it might not have enough power to kickstart the motor, so I gave it a little spin, and off it went. Ray told me about the commutator having a dead spot, so I tested it repeatedly, starting from a slightly different position. It worked flawlessly in all positions I tried.

I remounted the motor in the saw without connecting it to the linkage and plugged it into the controller board. Now it starts, but it makes a buzzing noise that is not there when it is running on the pure DC from a battery. I think this buzzing is caused by voltage fluctuation from the controller. It sounds like 60Hz, so the DC voltage is fluctuating, and there is also a lot of 60Hz ripple riding on the DC. I don't own an oscilloscope, so I can't check this.

 

I'm going to order a controller board.

[Blaughn]

19 hours ago, BadBob said:

I did some testing using a 2.5 HP DC treadmill motor. You can run it off of a car battery, a car battery charger, and a 20V DeWalt Lithium battery. A 9V Alcaline battery also works. My DC bench power supply did not work and was overloaded immediately.

I pulled the scrollsaw motor and connected it to a battery with it on the bench. Nothing happened, so it might not have enough power to kickstart the motor, so I gave it a little spin, and off it went. Ray told me about the commutator having a dead spot, so I tested it repeatedly, starting from a slightly different position. It worked flawlessly in all positions I tried.

I remounted the motor in the saw without connecting it to the linkage and plugged it into the controller board. Now it starts, but it makes a buzzing noise that is not there when it is running on the pure DC from a battery. I think this buzzing is caused by voltage fluctuation from the controller. It sounds like 60Hz, so the DC voltage is fluctuating, and there is also a lot of 60Hz ripple riding on the DC. I don't own an oscilloscope, so I can't check this.

 

I'm going to order a controller board.

Your troubleshooting is impressive.  I hope the new controller board does the trick.  To update an old adage:  To err is human.  To really screw things up you need "technology".  

[Scrappile]

That is not a real complicated looking circuit board,, To you have anyone near buy that can trouble shoot it.. like a a electronic shop.. Mavbe a simple inexpensive component that can be replaced.

[BadBob]

22 hours ago, Blaughn said:

Your troubleshooting is impressive. 

Thanks, I wanted to share this because I found it extremely difficult to find any credible information on troubleshooting DC motors and their associated electronics.

[BadBob]

I received the controller board today. I am currently reviewing the manual to make sure I get everything aligned correctly when I put it back together.

[BadBob]

I replaced the controller board. The voltage fluctuations are now about 0.5 volts DC, and the saw runs noticeably smoother. However, after running for about an hour, it stopped while running at full speed.

Voltages are good to the brushes. The commutator looks good from what I can see through the brush hole. I connected an ohmmeter to the motor leads, slowly turned the motor by hand, and got random readings. When applying power to the motor at the slowest speed setting and turning, it would start and run for a short period and then stop. The same thing happened at high speed. I suspect the brushes and have ordered a new set from Seyco. The brushes are not listed on the parts page. You need to call and ask for them. Brushes are cheaper than a new motor.

This photo shows the controller boards with the new one on the left. Note the sealed trim pots on the old board. I had to adjust the new board to get the same voltage as the old one. The motor is a 60-volt motor, but the most I can get out of either controller board is 50 volts. I have yet to find out what the correct output is. The trim pots adjust the maximum and minimum voltage output.

 

[BadBob]

The new brushes were considerably longer than the old brushes. I installed them but no joy. There is power to the motor but it isn't moving at all. I ordered a new motor.

[Blaughn]

2 hours ago, BadBob said:

The new brushes were considerably longer than the old brushes. I installed them but no joy. There is power to the motor but it isn't moving at all. I ordered a new motor.

I feel your pain.  I hate it when a repair turns into a guessing game with a stiff price attached to each guess.  I hope the new motor will solve the problem.  Keep us posted.

Bruce

[kmmcrafts]

Well that really sucks, I admire your knowledge of the testing of the components as I don't know a thing about electronics..and would have just thrown parts at it until something fixed it, LOL.. though that's kind of where it ended up for you anyway.. maybe there was a couple different issues that shorted the motor? 

My saw has been acting up for nearly a year now.. it's the speed sometimes will go wild.. I had been playing if off to the dust in the variable switch, used to blow the air gun around the area and take care of it for a while but now it doesn't seem to matter.. I'm thinking a new Pegas or something is in order but waiting for a possible holiday deal. IF this saw was a original Excalibur I'd repair it but it's not and it's been a total headache for me since day one.. Two rebuilds and only around 500 hours on it.. I have my moneys worth from it and want a new saw anyway so.. that's what I'm going to do..  

[BadBob]

11 hours ago, kmmcrafts said:

and would have just thrown parts at it until something fixed it,

That method would work and the saw is simple enough. Using that method I would start with the cheapest part and work my way up which is kind of what I did.

The real problem with trouble shooting these is that there are no specs available for the motor or the controller board. 

[OCtoolguy]

On 11/20/2022 at 5:15 AM, BadBob said:

That method would work and the saw is simple enough. Using that method I would start with the cheapest part and work my way up which is kind of what I did.

The real problem with trouble shooting these is that there are no specs available for the motor or the controller board. 

I know you replaced the brushes but did you clean up the armature and check it out with an ohm meter for possible shorts. 

[BadBob]

9 hours ago, OCtoolguy said:

I know you replaced the brushes but did you clean up the armature and check it out with an ohm meter for possible shorts. 

As best I could without disassembling the motor. The truth is that I got tired of messing with it. I may disassemble and repair it once the new motor is here. The failure happened at the worst possible time and is the second time my primary saw fail during the holiday season. I wanted it fixed.

[kmmcrafts]

23 minutes ago, BadBob said:

As best I could without disassembling the motor. The truth is that I got tired of messing with it. I may disassemble and repair it once the new motor is here. The failure happened at the worst possible time and is the second time my primary saw fail during the holiday season. I wanted it fixed.

Been there myself.. creates a stress in life because you don't want to throw money at it if it's something simple but at the end of the day you're possibly loosing money on sales / orders that you cannot do because a machine is down.. went through this as a customer from Hawk when I bought that new saw too.. and had been there so I was more than understanding with them for that reason.. but most customers don't get that and just want their items.. I also understand that.. LOL. 

Buy that new saw and then repair the old one.. it's a tax deduction and will help you through the busy holidays.. keep old saw and fix later or keep for parts for the new one someday.

[BadBob]

The motor came yesterday. It is installed and running fine. I cut an ornament with it last night.

The hardest part of swapping the motor was reconnecting the ground wires. I kept dropping the screws and them crawling around on the floor with a flashlight, looking for them.

When I first started it, there was a terrible knocking sound. After talking to someone at Seyco and reviewing the parts diagram, I removed the motor and reassembled it without the shims (washers) on the old motor shaft. These are not on the parts listed in the manual. I'm waiting for a call from Ray to see if these are necessary. The saw works fine without them, and the knocking stopped after I removed them.

I ran great now, but the arm would not raise. I knew I should have kept the tools out. After more disassembly and poking around, I figured out the problem. I had the wrong screws in the motor mount, and one was just long enough to hit the back of the arm and stop it from moving. The screws on the access panel are the same, but the motor crews have a stack of washers on each screw to stop them from going too deep.

Good for another few years.

 

[kmmcrafts]

28 minutes ago, BadBob said:

The motor came yesterday. It is installed and running fine. I cut an ornament with it last night.

The hardest part of swapping the motor was reconnecting the ground wires. I kept dropping the screws and them crawling around on the floor with a flashlight, looking for them.

When I first started it, there was a terrible knocking sound. After talking to someone at Seyco and reviewing the parts diagram, I removed the motor and reassembled it without the shims (washers) on the old motor shaft. These are not on the parts listed in the manual. I'm waiting for a call from Ray to see if these are necessary. The saw works fine without them, and the knocking stopped after I removed them.

I ran great now, but the arm would not raise. I knew I should have kept the tools out. After more disassembly and poking around, I figured out the problem. I had the wrong screws in the motor mount, and one was just long enough to hit the back of the arm and stop it from moving. The screws on the access panel are the same, but the motor crews have a stack of washers on each screw to stop them from going too deep.

Good for another few years.

 

Good to hear it's up and running again. Tip for those screws is a magnetic screw driver or just place a piece of painters tape on the bottom of the saw to stop them from falling to the ground and then having to do a search & rescue, LOL.. 

[Blaughn]

52 minutes ago, BadBob said:

The motor came yesterday. It is installed and running fine. I cut an ornament with it last night.

The hardest part of swapping the motor was reconnecting the ground wires. I kept dropping the screws and them crawling around on the floor with a flashlight, looking for them.

When I first started it, there was a terrible knocking sound. After talking to someone at Seyco and reviewing the parts diagram, I removed the motor and reassembled it without the shims (washers) on the old motor shaft. These are not on the parts listed in the manual. I'm waiting for a call from Ray to see if these are necessary. The saw works fine without them, and the knocking stopped after I removed them.

I ran great now, but the arm would not raise. I knew I should have kept the tools out. After more disassembly and poking around, I figured out the problem. I had the wrong screws in the motor mount, and one was just long enough to hit the back of the arm and stop it from moving. The screws on the access panel are the same, but the motor crews have a stack of washers on each screw to stop them from going too deep.

Good for another few years.

 

I repair project like that is so frustrating - kinda like an itch you can't scratch.  So glad you were able to get it running again.  

Bruce

[Sycamore67]

Glad to hear you are up and running again.

I sometimes will use a small piece of painters tape to hold a screw to the screwdriver.  Works well especially if screws are non magnetic.

Edited November 24, 2022 by Sycamore67

[BadBob]

21 hours ago, Sycamore67 said:

Glad to hear you are up and running again.

I sometimes will use a small piece of painters tape to hold a screw to the screwdriver.  Works well especially if screws are non magnetic.

I finally remembered that I had one of those gadgets that you can magnetize a screw drive with. It helped a lot.