Cordless angle grinder question

[Pitlamp]

I have a Makita cordless angle grinder which stopped working during a job today. I assumed I'd collected the wrong battery in a rush this morning and it was flat. But afterwards I found the battery I'd taken is fully charged - and works fine on other Makita cordless tools. So the problem must be related to the angle grinder itself.

When I clip in a freshly charged battery a small red LED on the grinder flashes quickly 4 or 5 times then goes out. (This is before pressing the slide switch to turn the tool on.)

I bought the angle grinder second hand so I have no instructions. Anyone got any ideas what the problem is and what the solution might be? Thanks.

 

[pwhole]

I can't find the paper manual for mine (DGA 456), but just found the online PDF version, and it has error codes shown on page 11:

https://www.icmsmakita.eu/CMS/custom/fi/attachments/user_manuals/User_manuals_EU1/DGA456.pdf

If yours is a different model, it'll be listed here:

https://www.makitauk.com/user-manuals

 

[Pitlamp]

Thanks - just had a look at that and it doesn't seem to have a "trouble shooting" section.
I was hoping somone might know the answer

 

[ChrisB]

Google suggests that the red light will come on during use if you're overloading the grinder, and it flashes at the start to show it's working, the same as the oil light, ABS light, etc, come on when you turn a car ignition switch. So it may be unconnected with the problem, which is quite possibly that the brushes have worn out - quite common when working in confined spaces where the dust gets sucked into the machine.

 

[Steve Clark]

As far as I know, the red light comes on if :

You are overloading it with too much load and it cuts out (not relevant here)

It is left switched on when you install a new battery (this is a safety feature to stop the blade spinning unexpectedly when you're holding the other end of the tool, presumably not relevant?)

The battery isn't fully engaged or the 3rd/middle pin/port is dirty or the battery thermistor has failed. This will give a slow flashing red light and not work. The 3rd pin connects to a thermistor in the battery. Some tools use this and some don't. Makita 'Star' protection. Hence you can get a situation where a battery with a 3rd pin failure won't work on a new modern tool with protection, but will still work on an older 2 pin tool or a simple USB adapter and the like.

Some kind of self test fault - brushes, wet inside, internal wiring failure.

Do try other batteries with it, it's often a confusing combination of tool, battery or charger that is the root cause of the problem with the 3rd pin. Possibly even the charger.


Anyway, for fun with makita chargers - if you want to change the tune that the charger plays when the battery is fully charged, just quickly remove and replace the battery in the charger within the first 5 seconds of putting the battery in. You can cycle through a few different jingles or back to the boring beep.

 

[pwhole]

My Makita charger has never played a tune when it's finished, despite it having a little graphic saying it does

 

[mikem]

Does it do the "boring beep"?

 

[Pitlamp]

Thanks folks, that gives me a lot to work with. (Think I'll avoid initiating the musical charger feature though!)

Guess I'll have to pull the grinder to bits and investigate further.

 

[pwhole]

Does it do the "boring beep"?

Not even that - just the green light and nothing else. I was looking forward to 'Yellow Rose of Texas' or some other witty tune

Pitlamp - which light comes on with yours, BTW? Not the battery light? I can't find any other indicators on mine.

 

[legendrider]

If in doubt, dismantle!

Grinders are mostly fresh air inside, and if the motor is goosed, they try to stiff you so much for a replacement its not worth the hassle, way easier to buy a new unit.

One of my Bosch 18V batteries threw a dicky fit and refused to take any charge. Taking the damn thing apart it was obvious that the charge indicator LED board was gebuggert . Snipped the 2 wires and removed and discarded the board, re-assembled the battery casing without.
Now the battery works a treat again, I just can't see how much charge is remaining. Not a problem underground as we generally burn through all our battery life in an evening.

 

[Pitlamp]

Not even that - just the green light and nothing else. I was looking forward to 'Yellow Rose of Texas' or some other witty tune

Pitlamp - which light comes on with yours, BTW? Not the battery light? I can't find any other indicators on mine.

It's a pair of red LEDs, one on either side near the top of the actual tool (behind a tiny translucent rectangular cover).

 

[mikem]

Older versions will have fewer options for entertainment!

 

[pwhole]

I just read the charger manual about changing the melody, and sadly, it seems I have a slightly defective model - at least as far as the melodies go, though it does charge batteries fine! It beeps twice when I first start charging, but never at the end, and is completely melody-free. Hardly a disaster though. It could be playing a Dua Lipa tune by next year, so watch out, new tool buyers

 

[Relict]

If you dismantle it take pics at every stage!

 

[owd git]

If you dismantle it take pics at every stage!

go brushless, prices will make long term sense/ value. in my opinion.

 

[Flotsam]

My surprise is that anyone is surprised that their battery grinder has gone faulty.

Spares costs usually make repair costs unviable, anything more than a basic look over is a waste of time. One suggestion could be to find a spares donor off ebay.

 

[bograt]

Stone dust created by cutting rock causes excessive wear on motor brushes, this should be your first check and is not a difficult repair.

 

[georgenorth]

My surprise is that anyone is surprised that their battery grinder has gone faulty.

Spares costs usually make repair costs unviable, anything more than a basic look over is a waste of time. One suggestion could be to find a spares donor off ebay.

I disagree. Brushless battery grinders (e.g. Milwaukee FSAG) can be extremely reliable. I’ve got one that’s been used nearly every day for work for the last 4 years and is still going strong. Totally agree regarding the cost of spare parts though.

 

[Pitlamp]

I was kindly sent the correct manual by another forum member. It’s quite useful and it looks like worn out brushes may well be the problem. They only cost a few quid and are easy to get at, so worth trying first.

I also agree with George that decent quality tools from reputable suppliers do last well if given reasonable care. Badlad put me on to Makita tools several years ago and they’ve proved to be excellent!

 

[john_tapeworm]

I have a Makita cordless angle grinder which stopped working during a job today. I assumed I'd collected the wrong battery in a rush this morning and it was flat. But afterwards I found the battery I'd taken is fully charged - and works fine on other Makita cordless tools. So the problem must be related to the angle grinder itself.

When I clip in a freshly charged battery a small red LED on the grinder flashes quickly 4 or 5 times then goes out. (This is before pressing the slide switch to turn the tool on.)

I bought the angle grinder second hand so I have no instructions. Anyone got any ideas what the problem is and what the solution might be? Thanks.

Turn it off and on again