Minimax MM16 Elec Switch problem - Fixed !!!

[Doug Shepard]

I just posted this over on Minimax Yahoo user group but thought I ask here too in the hopes that somebody here has any suggestions.

Last weekend I was doing a few cuts on the MM16 (4 mos old). At one point when I pressed the ON switch the saw started then after gaining full speed it then wound down and stopped. There have been occasions in the past when due to cold hands in the shop I just didn't get the switch depressed all the way and the saw only started up momentarily, although for less time than this instance. Thinking I had another similar case I depressed the switch again and got nothing. After checking for all the normal stuff I popped the doors open and checked the micro switches. Nothing seemed wrong there other than a bit of dust so I vac'ed them out good the pulled the switch box out and vac'ed out a bit of dust in there as well. The breakers weren't tripped and I checked it in another outlet on a different breaker and still got nothing. If I plugged the saw back in, I could hear the relay tripping at the switch so there's power getting to the switch. I also noticed with the switch pulled out of the column that there was a electric buzz that I hadn't noticed before. There's also no way the amount of cutting I was doing should have triggered any sort of saw protection circuitry. I did check the voltage at the outlet with a DVM but turns out I wasn't measuring correctly.

Contacted Erik Loza @ Minimax on Monday to ask questions. He said the buzz I heard was an indication of low voltage and suggested 2 things to do:
1) Pull the switch out and remove the white plastic cover then apply some WD40 to the mechanical movement parts of the On button switch
2) Turn the small white button inside the switch from 30A down to 25A

So today (another Saturday when MM isn't open) I tried one of the fixes and am still getting nowhere. Thought I'd ask here to see if there's anything anybody can recomment to try this weekend. Here's what I've got:
1) The voltage at the outlet measure 238V. I'm real reluctant to try turning the setting on the switch from 30A to 25A based on this.
2) After lubing the switch mechanism
With the saw unplugged the button seems to have a rough spot when you depress it and I THINK it's supposed to latch and stay depressed. I can only get it to stay in about 25% of the time.
With the saw plugged in there's supposed to be more resistance, but now it's REAL hard to push in.
3) The elec buzz sound from the switch is much louder than before with the switch out of the column.

Any thoughts?? Do I just have a bad switch or ??

[Tom Pritchard]

Doug, I had something very similar happen on my MM16, and what I found was that one of the switches that sense when the doors (upper door in my case) are closed was a little out of adjustment, and when the saw began running it was just enough to kick out the power to the saw! You can check this quickly by putting some tape on the door where the switch makes contact to close the gap between the switch and the door and trying it. If it works, all you have to do is adjust the switch so it's making good contact. I bet you have the same problem! Let me (sorry, us) know what you find! Good luck, this is an easy fix!!!!

p.s. The buzzing may be caused by the switch being right at the point of being made. I've seen it at my job before.

[Jim Becker]

Doug, do check all the microswitches as they could be out of alignment as Tom suggests...including the one on the foot brake. (A common one) And in the worst case, you could have a bad switch in the column. There have been occasional failures of the particular mag switches used in the past.

[Doug Shepard]

Tom/Jim
Thanks. I'll try the switch fix scheme and see what happens. The thing that's never made me suspect they're out of alignment though is that the day this started I made 4 or 5 cuts with no problem, then got the problem on the next cut - all with the doors never having been opened in-between. So you'd think there'd be no way for them to change. But I'm desperate enough to try anything at this point.


....
p.s. The buzzing may be caused by the switch being right at the point of being made. I've seen it at my job before.
I sure hope this isn't the case because the buzzing is with no switches depressed with me over at the outlet inserting the plug. I was going to retry the switch again with it out of the column and the saw plugged in, but after hearing the loud buzz thought I'd better skip it and unplug. There doesn't seem to be any metal in the switch box housing so I don't think it's got anything to do with not grounding of the switch to the saw due to it's being outside the column.

[Doug Shepard]

Well I tried the micro switch check with no luck. Looks like I'll have to check back with MM Monday. I'm probably done fooling with it for this weekend. It's been snowing hard for the last hour or so. I had to tidy up the saw and roll it back into the corner so I could get the car into the "shop". Looks like snowblowing and little woodworking will be on the agenda for the rest of the weekend.

[Tom Pritchard]

Well I tried the micro switch check with no luck. Looks like I'll have to check back with MM Monday. I'm probably done fooling with it for this weekend. It's been snowing hard for the last hour or so. I had to tidy up the saw and roll it back into the corner so I could get the car into the "shop". Looks like snowblowing and little woodworking will be on the agenda for the rest of the weekend.

Doug, sorry the switches weren't the problem. The more I think about it, Jim Becker is probably right when he suggested the switch might be bad. One nice thing is that I know MiniMax will work with you until your saw is fixed! They have a wonderful reputation, and that's part of why we buy their saws. Let us know what they say on Monday. Take care.

[Barry O'Mahony]

Does the motor turn at all now? If not, you may have tripped the overload protection. Look for a red button somewhere, probably around the controller.

[Doug Shepard]

Well I talked to MM a little bit ago and they're leaning toward thinking I've just got a lemon switch so they're sending me one out tomorrow. Thanks for all the help everyone.

[Doug Shepard]

The replacement switch showed up today and I just got it installed. The saw now powers up and seems to be working fine. Looks like the old switch was definitely the problem.

[Jim O'Dell]

Good news, Doug. Forget the Olympics, make some saw dust!! :cool: :D Jim

[Doug Shepard]

Good news, Doug. Forget the Olympics, make some saw dust!! :cool: :D Jim

I hear that! I've been monkeying with the electrical problem for the last 2 weekends with nothing to show for it. Time to get dirty!

[Alan Tolchinsky]

Doug, I had the same problem and MiniMax told me to increase the rating on the white dial. I didn't have your other symptom of buzzing but this increase did the trick. Glad to hear all is working well. Why do these switches have to be so sensitive and trouble prone? :(

[Doug Shepard]

Doug, I had the same problem and MiniMax told me to increase the rating on the white dial. I didn't have your other symptom of buzzing but this increase did the trick. Glad to hear all is working well. Why do these switches have to be so sensitive and trouble prone? :(

Well here's the really odd thing. Back when MM thought I had an undervoltage problem they told me to dial it down from 30A to 25A. Once I discovered I had 238V I thought it best to leave it alone so I never looked that closely at the switch or dial. After getting the switch swapped out yesterday I get looking closer and realized the new switch is not the same as the old one. Of course I discover this after MM is once again closed for the weekend so I emailed them. We'll see what they say Monday.

The old switch has AEG Part Nbr 910-201-211 and says "16..20A" and the dial was set at 20A.
The new switch has AEG P/N 910-201-212 and says "20..25A". The dial came set at 20A and so far I haven't changed it. The saw now powers up but I haven't done any cutting yet to put it under load with the new switch.
So based on MM's initial advice I'm wondering if I'm supposed to have a switch that says "25..30A" ??
Any MM16 owners care to pop the switch cover on theirs and see what AEG P/N and amp range their switch is (and what it's set on)?

[Alan Tolchinsky]

Hey Doug, I looked at mine and the range of the dial is within the rating of the motor on my saw. My MM16 has 14A stamped on the motor and the switch goes from 10A to 16A. I have it set to 14 since having a problem with it shutting off like yours did. I think originally it was set to lower than that but I don't know the exact setting.

I think my voltage was too high coming into my house though when I had my problem. We had a power transformer go out the same day my trouble with the saw started. I had just measured the voltage and it had gone up to 250 or so. After they replaced the transformer the voltage is now back to 240. It seems like the higher voltage caused the problem at the lower setting on the switch but I'm speculating here. All I know is I increased the dial setting and all was back to normal.

Does anybody know if the "A" stands for amps on the plate? All the other ratings are metric so I'm wondering what this really stands for. If I recall, most motors have "amps" in the rating placard so you know what they're talking about. So what's the "A" really mean? Inquiring minds want to know.

[Alan Tolchinsky]

O.K. I reread your post.

" The old switch has AEG Part Nbr 910-201-211 and says "16..20A" and the dial was set at 20A.
The new switch has AEG P/N 910-201-212 and says "20..25A". The dial came set at 20A and so far I haven't changed it. The saw now powers up but I haven't done any cutting yet to put it under load with the new switch"

Since both switches were set at 20A I think you should be in good shape. It's just that the new switch has a higher rating that they probably use for some of their bigger machines. Make sense? But with the variable "A" switch it can be set to match several of their machines using one part instead of having to stock different ones. I'd still call them to be sure. (My lawyer told me to say that. :) )

[Doug Shepard]

Alan
Thanks for your input. I went back and looked at the motor plate later and mine says 18A, which sort of makes you wonder about my new switch that goes from 20-25. But wait - there's more. All I did yesterday after swapping out the switch was test the switch a dozen times or so - no cutting or tension on the blade. It turned on every time so I thought the problem was licked. Today I hit the switch a couple more times and all is well, so I start getting ready to cut some wood. I tension up the blade and set the fence up where I want it, then hit the switch. :eek: NOTHING.:eek: Just the terrible stench of the smoke coming out of my ears.

After calming down a bit I remembered your post and dialed up the switch all the way to 25A (this is before I read the 18A rating on the motor plate). Voila - it worked. Most of the time. I still had a case or two when it wouldn't turn on, but for the most part it was OK. At least this time when it wouldn't start there was a faint but clearly audible sound indicating it was trying to start the motor - something I hadn't heard at all with the old switch or with the new switch dialed in at 20A. This just keeps getting wierder. Apparently tensioning the blade provided just enough load that I couldn't start it up set at 20A ?? The cutting I was doing was just through 3/4 clear mahagony about 2' long - not any major resawing. But I'd do a few cuts with shutoffs in-between then get a no-start again. A couple of cycles of off/on/off/on and I could get it to start again. So my experience says I should dial the switch up even higher if I could and all would be well, but the 18A rating on the motor says otherwise. I checked the voltage again today and it was at 237V so no major change. Looks like the story on this fix isn't quite over yet.

[Jim Becker]

Startup current and running current are two different animals...hence, the necessary higher setting on the overload protection. But I do think you need to call MM again on Monday as it should fire up every time, not most of the time. Something else may be amiss that is increasing the load and shutting things down.

[Alan Tolchinsky]

Doug, So sorry you are still having trouble. I'm sure Mini Max will set you straight. Let us know what happens. It will be fixed! Alan

[David Less]

I'm having switch problems too on my new MM16. I've fried out 2 so far. The first I believe was a mechanical problem with the black button, it was frozen and I could not turn the saw off. After recieving a new coil (which did not fix it), MM sent a new swich. The switch worked for about 6 or so starts then nothing happened. I checked the voltage across each motor leg (to ground) which was 120 volts but when checking together I did not get 220v. After disecting the switch and scamatic I found that the middle contact was burnt. I checked the continuity across the middle contacts and it prooved me correct. I moved the middle connections to the far right contacts (removed the jummper, black wire) and every thing workd fine. Put back together and was able to finish up my wife's sofa table. Boy that was close. I will call MM for another new switch on Monday. T was contemplating replacing with an AB or Cutler Hammer starter but would require a lot of work to make it look stock.

David

[Mike Archambeau]

Well it looks like it is my turn to wrestle with the electrical problems on the MM 16. Great saw, but fragile in the electrical department.

My saw shut off during a cut. The motor tries to restart, but never comes up to speed before shutting itself off. This happens even when the blade is not tensioned. The drive wheel spins freely and smoothly.

My machine uses the 3.6 kw motor (4.8 hp). The motor plate says the motor draws 20.8 Amps.

My AEG switch is as follows: Mbs 25; 16......20 Amps; E-Nr. 910-201-211

For those of you that have replaced your starter switch, what is the part number for the switch that was rated for more than 20 amps?

[Sam Blasco]

This doesn't sound like a switch problem, but an electrical one or motor or both. I'm no electrical expert but you should contact tech support at SCM. Could be a bad capacitor. Most switch problems are due to the micro-switch coil that lets the main switch know if it can come on or not. If that was the problem you would have a limp "on" button -- nothing would happen. The motor wouldn't attempt to start.

[Van Huskey]

Sounds like a capacitor problem.

[David L Morse]

I agree, it sounds more like a motor problem than a switch problem. If you're lucky it'll be a capacitor.

[Mike Archambeau]

Sounds like a capacitor problem.

Just got off the phone with tech support. And that is where they are steering me. When I opened the box that contains the capacitors, I noticed that the large 160 mf capacitor had a jumper across two terminals with what looks like a resistor being used as the jumper. It looks like it got hot and burned, leaving some heat marks on the plastic insulators. The tech support team member thought my new capacitor would not need the jumper, and if it did, it would come with it installed.

Any good ideas of where to find the capacitors?

[Van Huskey]

Any good ideas of where to find the capacitors?

I buy them at a local HVAC supply house. Get one with the same capacitance in mF and equal or higher voltage as compared to the original.

[Malcolm McLeod]

Any good ideas of where to find the capacitors?
Search "Allied Electronics" (no connection) if you have limited access to local suppliers. They have a huge selection, but be careful you get correct specs - both electrical and size. It can be easy to find the right capacitance/voltage, and a real bear to find a size that will fit inside the cover on the motor.

[Mike Archambeau]

Search "Allied Electronics" (no connection) if you have limited access to local suppliers. They have a huge selection, but be careful you get correct specs - both electrical and size. It can be easy to find the right capacitance/voltage, and a real bear to find a size that will fit inside the cover on the motor.

I tried the Allied Electronics webs site but I was not able to locate capacitors with the right specifications. So I called Grainger and used the live chat function. The guy who helped me was able to locate the right capacitors very quickly. I should have them in a couple of days and find out if the temperamental Eye-talian machine is happy again. Fingers crossed......I have work to do.

[Mike Archambeau]

I tried the Allied Electronics webs site but I was not able to locate capacitors with the right specifications. So I called Grainger and used the live chat function. The guy who helped me was able to locate the right capacitors very quickly. I should have them in a couple of days and find out if the temperamental Eye-talian machine is happy again. Fingers crossed......I have work to do.

Well the new capacitors did not do the trick. I am going to have to track down the resistor that is the jumper on the original capacitor. If anyone has a 2005 vintage MM16 with the 4.8 hp motor (3.6 kw), and you re willing to open the black box mounted on the motor, I would be grateful if you can identify the little black resistor used as the jumper.

I will try to engage with MiniMax technical support again in the morning. Fingers crossed.

[David L Morse]

Well the new capacitors did not do the trick. I am going to have to track down the resistor that is the jumper on the original capacitor. If anyone has a 2005 vintage MM16 with the 4.8 hp motor (3.6 kw), and you re willing to open the black box mounted on the motor, I would be grateful if you can identify the little black resistor used as the jumper.

I will try to engage with MiniMax technical support again in the morning. Fingers crossed.

The normal function of a shunt resistor on the starting capacitor is to bleed off any charge left there after the centrifugal switch opens when the motor comes up to speed. A charge left on the starting capacitor can cause undesirable vibration on shutdown after the centrifugal switch closes. The resistor is not required for proper starting.

[Mike Archambeau]

The normal function of a shunt resistor on the starting capacitor is to bleed off any charge left there after the centrifugal switch opens when the motor comes up to speed. A charge left on the starting capacitor can cause undesirable vibration on shutdown after the centrifugal switch closes. The resistor is not required for proper starting.

Well Grainger has the resistor, and they promised 1 day delivery. So tomorrow I find out if the new resistor allows that fine eye-talian motor to spool up. Fingers crossed. Tonight I might dream about Baldor and Leeson, American made electrical motors........

[Mike Archambeau]

Well both capacitors are new. The resistor is new. Still no start. The breaker trips as soon as you push the start button. The breaker trips even though the drive belt has been removed. The motor spins freely by hand though. Perhaps it is something inside the motor itself? I wonder if the start circuit inside the motor is not closing properly. Anybody ever opened their motor up to have a look inside?

[John Lanciani]

I'm going to make a diagnosis based on both the described symptoms and personal experience with a CEG motor similar to the ones MiniMax uses; the last time that the saw started successfully the centrifugal switch failed to open. This in turn caused the start winding to remain energized while the motor was running. The start winding overheated and shorted out, causing the overload to trip and stop the saw. Now the motor can not start due to the shorted start winding and repeated attempts to start it have burned the run winding causing a dead short that is tripping the breaker.

Hopefully I'm wrong but I would bet a round of drinks that you will be in the market for a new motor. Unfortunately it is a metric frame motor and if I'm right you are going to be mighty upset at the price of replacement.

[Mike Archambeau]

I'm going to make a diagnosis based on both the described symptoms and personal experience with a CEG motor similar to the ones MiniMax uses; the last time that the saw started successfully the centrifugal switch failed to open. This in turn caused the start winding to remain energized while the motor was running. The start winding overheated and shorted out, causing the overload to trip and stop the saw. Now the motor can not start due to the shorted start winding and repeated attempts to start it have burned the run winding causing a dead short that is tripping the breaker.

Hopefully I'm wrong but I would bet a round of drinks that you will be in the market for a new motor. Unfortunately it is a metric frame motor and if I'm right you are going to be mighty upset at the price of replacement.

I am afraid you are correct. Are these motors repairable by a motor shop? If not, do you know where to purchase a replacement?

[John Lanciani]

A good motor shop can rewind it, expect to pay +/- $300.

[Mike Archambeau]

A good motor shop can rewind it, expect to pay +/- $300.

I can live with that. But I feel like these motors should be more reliable and robust than they are. I managed to find a shop in Hartford, CT. They have been in business since 1934. And the head of operations there told me to bring in the motor and they will check it out for me.

Thank you everybody who chimed in with helpful advice. It is very much appreciated.

[Jim Becker]

I don't recall seeing much posting about motor issues for the MM16, so this might just be "luck of the draw" that you're having an issue with yours. Some switches, yes, but motors, no. At least to my recollection.

At any rate, hopefully, the motor shop you found will get you fixed up if it is indeed an issue with the motor itself.