FLEX 3401 not working right, erratic speed... Please diagnose!

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joeybsyc

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Hi there, I've been searching the forums and Internet looking for someone with the same problem do I know what needs replacing, as in on a limited budget and don't use my flex daily... Here is the issue I've been experiencing:

The speed seems to vary as I'm using it... Like I can be on speed 5 or 6, but pull the trigger and sometimes the speed acts like 2 or 3. The control wheel seems slow to react to changes, and sometimes you can even hold the trigger in with the machine running and turn the speed adjustment with no actual change to the speed of the machine at all, or a very slow reaction to the speed change on the dial.

Now my first thought was that it's gotta be the speed controller assembly (over 70.00 plus shipping) but after reading some other posts including one just below this one, I am now thinking it could simply be the brushes... Which quite honestly aren't cheap either at about 40.00 shipped for a pair. Other posts I've seen speak about the trigger switch itself causing similar issues, but I honestly don't think that's my issue. Cord is good for sure. I don't want to buy a half dozen expensive parts trying to fix one issue... But also don't want to buy the wrong part.

I've even considered just buying another one and selling mine to someone else who knows what it needs... As used ones seem to sell for quite a bit, even with issues... And i don't know what parts to buy to fix this one. That seems like a potentially expensive solution though. I am looking for help!

It's a few years old, but hasn't been used more than a dozen times I'd guess. Although those were all full details, some being large pickups and SUV's. Any ideas would be appreciated, but hoping to hear from someone who has experienced this exact issue and knows for certain what fixed it.
 
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FLEX is fast!

I called Chris Metcalf and also sent him an e-mail with the link to your thread, he sent it to Davey Snyder at PowerhouseToolParts.com the official repair facility for FLEX tools and here's what Dave had to say,


From: Dave Snyder <[email protected]>
Date: April 7, 2017 at 7:00:39 AM MST
To: 'Chris Metcalf' <[email protected]>
Subject: RE: FLEX 3401 not working right, erratic speed... Please diagnose :)

Of the more common possibilities that could cause problems like that described, the first being cord problems at the end of the strain relief where all the flexing occurs.

Many times this is mis-diagnosed by those attempting their own repairs. The way to properly diagnose it in this particular situation is to lay the tool down on it's back on a work bench and not move it as the switch is triggered to the [ON] position and locked into place.

If it operates, then bend and twist the cord at that point to prove that it is definitely not the cord.

If bad, the unit will stop and not restart till the switch is released and then restarted.

This is THE most common problem. That doesn’t mean to say that there are other things that could occur, such as loose connections elsewhere, sticking brushes, loose brush springs, faulty switch or speed control, or other possible scenarios.

I wouldn’t recommend attempting repairs unless you have a basic knowledge of electricity, and understanding of volt/amp/ohmmeters, otherwise send it in or entrust it to those that do understand.

Otherwise it is a guessing game and everyone’s time just gets wasted.

Dave Snyder
[email protected]
Power Tool Service and Parts Supply - Omaha, NE | Powerhouse Distributing

Powerhouse Distributing
11011 i ST
Omaha, NE. 68137

PH: 888-809-4749
FX: 888-809-4748




:)
 
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For everyone reading this into the future, two comments... (not directed at you Joey, I just practice typing for the future)


First - If and when a FLEX tool breaks it's the exception not the rule. These are the Mercedes-Benz of polishers. The if and when a tool breaks it can often be traced back to a non-tool reason. See my next comment.


Second - Talking to Chris Metcalf, he said the MOST common cause for failure of any of the electronic parts inside ANY tool, be it a FLEX, DeWALT, Porter Cable, fill-in-the blank, it's due to using too wimpy of an extension cord. And Chris says from his experience in this industry he sees guys using cheap extension cords with to small of gauge wire all the time.

In fact it is such a problem that FLEX took the proactive step to introduce their own heavy gauge extension cord to,

A: Solve the problem.

B: Educate the public


In fact, I have an article on this... (yeah I know, sometimes even I can't believe I have an article on extension cords)


Sneak Peak! FLEX 50 Foot Heavy Duty Extension Cord - Tool Insurance and Power Efficiency



The problem
If you use to light of gauge wiring in and extension cord the wire itself hinders the flow of electricity to the tool. This can harm the electrical components inside the tool and cause these components to burn out. The cord itself will get hot due to the impedance of electricity flow. In fact, you should NEVER feel heat or warmth coming from your extension cords when using FLEX tools. If you do this is sign that the cord is too light duty for the tool.

The solution
A heavy duty extension cord that uses a minimum of 12 AGW wire. The longer the cord the more important it is for the cord to use 12 AGW wire. The FLEX 50' Heavy Duty 12 AGW Extension Cord is the solution FLEX offers all their tool customers to protect their tool investment while providing the correct flow of electricity to the tool.


FLEX_HD_50_Xcord_001.jpg



So when you invest in high quality, high dollar tools, include in your budget some funds for the appropriate heavy gauge extension cord. It will protect your tool investment.


On Autogeek.com


FLEX 50 ft. 12/3 SJTW HD Extension Cord




:)
 
Thanks Mike... I will look into that when I get home from work, but I honestly do not think the problem is with the cord. I also will admit I'm no electrician! What kind of a deal could you give me on a brand new one? Any specials or sales coming up on Flex 3401's? [email protected]
 
Mike Phillips said:
. If you use to light of gauge wiring in and extension cord the wire itself hinders the flow of electricity to the tool. This can harm the electrical components inside the tool and cause these components to burn out. The cord itself will get hot due to the impedance of electricity flow.
Click to expand...

I have heard this many times but I have never heard a good explanation of what happens. The cord getting hot means the heat (due to voltage drop) is being dissipated in the cord, not the tool. Can Chris explain how excessive voltage drop in the extension cord causes components inside the tool to burn out?

If you have voltage drop in the cord, that means the tool isn't getting 120 volts, but some lesser voltage. Since the winding resistance of the motor is a constant (notwithstanding how the speed control works), then using Ohm's Law, the tool would be drawing less current than normal, less current should mean less heat, less heat does not equal burning out, at least in my mind.

So to me, the end result would be the tool running slower or not having as much power as normal, not burning out. Unless of course you are more likely to stall the motor since the tool isn't at it's full power output, and stalling would certainly create a lot of heat as the cooling fan wouldn't be turning. Of course this could be some motor thing that I don't understand, which is why I'm asking.
 
joeybsyc said:
Thanks Mike... I will look into that when I get home from work, but I honestly do not think the problem is with the cord. I also will admit I'm no electrician!

What kind of a deal could you give me on a brand new one?

Any specials or sales coming up on Flex 3401's? [email protected]
Click to expand...



Sorry to say... I'm not the wheeler-dealer here at Autogeek. I'm more of the how-to guy.

I can check with Andre as he IS the wheeler-dealer guy here at Autogeek about any sales or good deals.


:)
 
Cool...hopefully the official autogeek "wheeler/dealer" can hook me up with a good deal on new Flex and I can get back to polishing ASAP! Thanks again...
 
Mike Phillips said:
.


For everyone reading this into the future, two comments... (not directed at you Joey, I just practice typing for the future)


First - If and when a FLEX tool breaks it's the exception not the rule. These are the Mercedes-Benz of polishers. The if and when a tool breaks it can often be traced back to a non-tool reason. See my next comment.


Second - Talking to Chris Metcalf, he said the MOST common cause for failure of any of the electronic parts inside ANY tool, be it a FLEX, DeWALT, Porter Cable, fill-in-the blank, it's due to using too wimpy of an extension cord. And Chris says from his experience in this industry he sees guys using cheap extension cords with to small of gauge wire all the time.

In fact it is such a problem that FLEX took the proactive step to introduce their own heavy gauge extension cord to,

A: Solve the problem.

B: Educate the public


In fact, I have an article on this... (yeah I know, sometimes even I can't believe I have an article on extension cords)


Sneak Peak! FLEX 50 Foot Heavy Duty Extension Cord - Tool Insurance and Power Efficiency



The problem
If you use to light of gauge wiring in and extension cord the wire itself hinders the flow of electricity to the tool. This can harm the electrical components inside the tool and cause these components to burn out. The cord itself will get hot due to the impedance of electricity flow. In fact, you should NEVER feel heat or warmth coming from your extension cords when using FLEX tools. If you do this is sign that the cord is too light duty for the tool.

The solution
A heavy duty extension cord that uses a minimum of 12 AGW wire. The longer the cord the more important it is for the cord to use 12 AGW wire. The FLEX 50' Heavy Duty 12 AGW Extension Cord is the solution FLEX offers all their tool customers to protect their tool investment while providing the correct flow of electricity to the tool.


FLEX_HD_50_Xcord_001.jpg



So when you invest in high quality, high dollar tools, include in your budget some funds for the appropriate heavy gauge extension cord. It will protect your tool investment.


On Autogeek.com


FLEX 50 ft. 12/3 SJTW HD Extension Cord




:)
Click to expand...


I have to agree with Mike on this! When I heard Chris Metcalf speak about best practices when working with Flex Polishers at the Indianapolis Motor Speedway and the power cord was the top problem found, I was a bit skeptical. But after a weekend using proper size cords and feeling the difference in the machines, I couldn't deny the improvements in power tool operation!
 
Great thread. Extension cords are something we rarely think about, yet they are very important for the health of our power tools.
 
I love that Flex has a cord specifically for these tools. I've always loved the cords in their tools - high quality, easy to manage.

I need to consider these on my next order. It's time to upgrade my extension cords as it is.
 
Well, I took it apart and cleaned it, sprayed electronics cleaner on everything and it seemed to help. The speed selector doesn't react super fast, but seems to hold the speed I set it at. I'm thinking it's either the speed selector switch or the trigger itself. If these ever go on sale I may buy a new one, but for now I guess I'll keep on chuggin' along with this one.
 
Probably the electronic module, aka speed selector. I've seen a couple with this problem. If it is, it will be a bit costly, around 90$ for the part alone.
 
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