REPAIRING MAKITA LI-ION 18V LXT CHARGER DC18RA ETC

REPAIRING / FIXING MAKITA LI-ION 18V CHARGERS

BY SCHMIDTTOOLS

Hi again folks,

Here`s a quick guide that hopefully helps a few folks out with their broken makita li-ion chargers.

Makita currently makes a few li-ion chargers and they can be temperamental.
The most commonly known charger is probably the dc18ra rapid charger, they also make a couple of older versions and a 12v car version too.

Currently there`s:
DC18SC (older 45 – 60 min charger), Blue (1st Generation – Discontinued)
DC18SD(usually black also 45 – 60 mins, no fan inside either.), (2nd Generation – Current Model)
DC18SE(auto car charger) & (3rd Generation – Current Model)
DC18RA rapid charger (22min charge time). These come in black and blue coloured versions. (3rd Generation – Current Model)
The DC18RA is the best model to have, it has the fastest charge times and is fan driven.

They are all essentially the same inside and all suffer from the same 3 most common problems that can be fixed.
THE MOST COMMON PROBLEM WITH THESE CHARGERS IS THE FUSE.

If the fuse blows, then the charger stops working all together and is just dead when you plug it in.
Simply a matter of removing the rubber plugs and the 4 screws from the bottom of the charger.
Making sure of course the charger is not plugged into a power point.
Common sense prevailing!!

Taking of the top cover and testing the fuse (top right corner of pic below) with a multi-meter. There`s also a glass fuse over on the other side of the transformer. You can usually see that one if it`s blown.

If the fuse is blown then this job is best handled by an electronics repairman since there`s probably a reason it blew, such as a poor or blown varistor or failing capacitor, unless you had the charger on a generator or something and you know it blew from a power surge, i guess you could take a chance. I`d still recommend getting a pro to check it out to make sure other components weren`t damaged. Unless your handy with a soldering iron and prepared to find a replacement fuse and test other parts, best to leave that to a professional. They are no ordinary fuse and not all that easy to come by. Electronics parts wholesalers is the best place to find those. Any repairer who repairs mobile phones, computers, T.V`s, etc, etc should be able to handle this job for you hopefully at much less expense than a replacement. Or you can send them to us and we can fix it.

The next in the list of common problems is the fan.

These do fail regularly in DC18SD`s and DC18RA`s that have a fan in them and depending on where you charge your batteries, some people have more trouble than others.
The fan of course will suck in dust, so those guys using them in dusty workplaces will have more trouble with these than other people working in cleaner environments.
Best not to plug them in, in a room full of plaster & saw dust or in the dirt outside on the ground. Outside up on a window ledge in the shade somewhere or on clean concrete or something is a much better place to charge up.

If the fan stops working then after a couple of minutes of charging the battery the charger should stop and indicate an error.
You will be able to hear that the fan is not working. So this is a really easy problem to diagnose.
Simply plug the battery in and listen for the fan.
If the fan is not working, grab a replacement fan and fix it yourself. It`s a 5 minute job, with no soldering and a phillips head screwdriver being the only tool you need.
We usually will have those fans in our online store as a replacement part.

Follow the steps above and pull the rubber plugs out of the charger base and remove the 4 screws and top cover. Making sure the charger is not plugged into a power point. Once again, common sense. You don`t want to get a zap.
You`ll notice just to the left of my finger in the shot below the other glass fuse referred to earlier.

You`ll see the plug for the fan located where my finger is pointing in the picture above.
Unplug that and remove the fan and wires. Once again just to be sure folks don`t hurt themselves make sure the charger isn`t plugged in when you do this. There`s no need to have juice flowing through it and even though that`s a 12V dc output on that part of the circuit there`s still other live 240v spots on the board so for your own sake don`t have it plugged in when you do it. We don`t want to have a simple fix-it job become a trip to hospital.

The fan isn`t screwed into place. It`s easily removed. It`s just held in place by the cover.

Slot in your new fan, plug it back in, replace the top cover, screws, and rubber plugs and off you go again.

And hey presto, back to new and functioning in under 10 minutes.

THE NEXT COMMON PROBLEM IS THE CAPACITOR.

Now this is a job for a professional or at least someone who has a fair bit of a clue with electronics and testing capacitors. That main capacitor seems to have a habit off failing. It usually goes up in a puff of smoke.

So if you`ve tested the fuse and you don`t know how to test the capacitor then stop right there and take it to a pro who knows what he`s doing. The capacitor can be obviously damaged sometimes and you can occasionally clearly see it`s melted and oozed oil everywhere. It all depends if it`s just failing or completely destroyed itself. If it`s had a melt down you`ll see it`s usually melted the plastic cover and popped and sprayed oil out and the charger had a puff of smoke come out and you looked at it and thought…..Well that can just never be good when that happens.
You`ll also smell it`s melted.

If the capacitor is just failing then usually the charger will still appear to work but any battery you try to charge will immediately flash and the charger will beep indicating a dead battery. Either that or the thing has just gone pop with some smoke and blown the fuse also, one or the other will happen. If you`ve tried a few batteries and the charger appears to be working and you know they can`t all be dead then the main capacitor is usually the problem. There are of course other components that can fail but from all the chargers i`ve ever seen that are broken and all the customers i`ve talked to they all seem to have the issue with either the fan, fuse or that large main capacitor. But of course i`m sure there`s lots of times where it could be another smaller component like a transistor, diode, the transformer or any other of the numerous components.

If you have a friend with a makita kit which everyone does, don`t they? Borrow one of his batteries if you need to and try to charge it or try to charge one of your batteries in his charger to confirm if it`s a charger problem or a battery problem before you run out and buy a new charger or a stack of batteries. We have seen many times when customers have 2 dead batteries and lots of times when it’s the charger causing the problem and not the batteries, so it’s best to find out before you rush out and buy something. Your local tool store should also be able to test it for you, providing they are help full that is. We do anyway, so if they won`t and your close by to us in Melbourne then bring it down and we can check it out in 2 minutes flat. We do also replace main caps in these and fuses, etc. So you can always drop a charger in for reapirs or send it to us to check out.
Testing and replacing the main capacitor involves being exposed to the risk of electric shock, so i highly recommend unless you repair equipment professionally and know what your doing, and you know how to discharge a capacitor properly, that you take it to someone who does and can test it for you.
With a quick 5 minute soldering job and a replacement capacitor this can also be fixed pretty easily. The capacitors are not particularly cheap though and need to be exactly the same voltage and pf rating, they also need to be the right size to fit into the allocated space on the pcb. So at this stage you might just be thinking it`s probably easier to go grab another charger. Well you can always send it to us or drop it in and we’ll do it for you.
But if you`ve got the time on your hands and you enjoy little fix it jobs then go for it yourself. It’s not particularly difficult.

I hope that helps someone out.
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I hope the guide wasn`t too boring but it was hard to explain properly in any less space.

UNTIL NEXT TIME TAKE CARE AND ALL THE BEST.

BRENDON @

SCHMIDTTOOLS