Milwaukee Circular Saw Repair - Revisit - Let's fix it this time!

I'm taking another look at the Milwaukee Saw that had the blown motor controller chip, as one of my viewers Scott kindly sent me some parts from some broken saws that he had.
Let's see if my original diagnosis was correct, and if we can successfully repair it this time!

[@599miata]

I did not see the first part of you repairs but you could not find the trouble with the small board? Nice of that person to send you two spare control boards to you. 😊😊👍👍

[@BuyitFixit]

Yes, unfortunately it was the main IC on the board which is a custom part and contains proprietary firmware 🙁

[@jonathanwright1507]

I just fixed one of these this week with intermittant working, measured changing resistance across the small cables switch instead of continuity beep, I just opened the switch cleaned all contacs & re-greased, now works perfect,. Your videos helped me understand the insides & did you know the switch would of cost £33 UK Sterling to replace!!!!

[@BuyitFixit]

Nice, well done 👍Yes the parts for some of the tools are almost as expensive a buying a replacement tool! The sander I looked at a while back was £77 for a replacement motor assembly. A new sander could be bought for £99. I found a replacement motor on Aliexpress for £9 🙂

[@jonathanwright1507]

@@BuyitFixit - The switch contacts are removable, so if this was a Bosch product they would sell all the small bits, Milwaukee brands work good, but bad for repairs.

[@user-te1le7ck6b]

Great you was sent the part 👍👍

[@sp523]

I really liked this video. Just found your channel and I subscribed.

[@BuyitFixit]

Thanks SP I really appreciate your comment and sub! If you have any suggestions of stuff you'd like to see me try and repair let me know.

[@sp523]

Your content is great. I’m working my way through your videos and I have enjoyed every one that I have watched so far. Keep up the great work!

[@BuyitFixit]

Thank you so much. I had been getting a little disheartened with it all (self doubt), but it's comments such as yours that inspire me to keep going!

[@sp523]

I found your channel from your comment on My Mate Vince’s channel on the repair of the Milwaukee angle grinder today. Maybe you guys could do a collaboration on something to help boost your channel. I’ve seen that you have many Milwaukee tool repair videos.

[@BuyitFixit]

I spoke to vince a few times now on messaging. We had a bit of a chat on the frogger video I did and he said he would give me a shout out when he uses the little grinding pen he was asking me about.

[@charlessmith8609]

What were the name of the first components that you replaced and where did you purchase the parts at can they bought at any electronics shop or is it special ordered

[@BuyitFixit]

Hi Charles. They are called mosfets. You'll need the number off them. I think IRLS3034TRL7PP possibly, you're best off checking your unit to make sure.

[@jamesguelchi8682]

Hi, do you carry out repairs for anyone, and how much do you charge for that repair you have just done? many thanks

[@jumanpu1164]

Buen video👍👍 dime sabe si estás tarjeta de control del motor de la sierra usan MICROFUSIBLES? Pregunto porq Vi q un taladro dewalt dcd996 no funcionaba solo prendía su luz un segundo y no funcionaba el taladro y cuando lo reviso encontró q en su tarjeta encontró dañado sus MICROFUSIBLES los cambio y funcionó pregunto porq quizás los fusibles están ahí como protección al motor y por eso la tarjeta no funciona solo porq el fusible no da paso a la corriente. Saludos

[@BuyitFixit]

Gracias. 👍Hay un microfusible en el tablero, pero estaba intacto. Creo que cuando los mosfet originales se acortaron, alimentaron un voltaje más alto en el chip y explotaron el precontrolador del motor.

[@jumanpu1164]

@@BuyitFixit gracias por responder soy de Perú 👋 y no encuentro mucha información a mi problema solo una consulta quizás puedas ayudarme y es que no prende la sierra circular dewalt 20v ( dcs 570 es el modelo) en KZbin verás el problema que describo de gente consultando cuál sería el problema pero no hay nadie solucionando y está sierra solo prende su luz un segundo y también bota un sonido de un segundo pero no funciona lo curioso es que saque su motor no ví nada dañado o quemado lo volví a poner en su lugar, lo prendí la sierra y funcionó pero solo un rato y volvió a botar ese sonido, además de eso note que dos cable que entran al motor salen dos cables que va hacia el condensador y cuando los toco estos se siente caliente incluso aumenta su temperatura cada vez que intento prender la sierra. Por lo menos se que la corriente le llega hasta el motor, creo por qué sino no se sentiría caliente, aunque no me parece normal, pero alguien comento que cambio de condensador pero el problema persiste. UD que opina, que cree que pueda ser gracias por su comentario y si hace un vídeo de está sierra, Miles de persona que me di cuenta le estaremos agradecidos si decide hacer un vídeo con subtitulos porfa 😂 el que me pasó tu canal también tiene el mismo problema por eso estamos buscando ayuda saludos

[@BuyitFixit]

Trataré de estar pendiente de uno roto. Has mirado los mosfet? ¿Supongo que habrá algo en la parte posterior del motor? Son una causa común de falla en los motores sin escobillas de Milwaukee.

[@jumanpu1164]

@@BuyitFixit gracias, te comentaré que tal me fue saludos compañero.💪🇵🇪🇵🇪🇵🇪tienes un suscritor nuevo

[@BuyitFixit]

Gracias👍

[@sovietchannel6218]

Where can I find one of those control boards

[@BuyitFixit]

Unfortunately Milwaukee don't sell them separately. They only sell the whole motor assembly with the control board attached, and I think it wasn't far off the price of a new saw! A viewer kindly sent me one from another failed unit that he had spare...

[@richardtaylor7199]

I will put the axe away then.🤣🤣🤣

[@BuyitFixit]

😂😂😂😂👍

[@jameswells2526]

Hi mate, my saw seems to have a similar fault but I know nothing about electronics. If I was to send it to you would you be interested in taking a look at it for me if I pay you? Cheers

[@BuyitFixit]

Unfortunately I dont take in repairs. And if the fault is the same as this one then unfortunately it seems parts aren't readily available. If it's just the mosfets then it may still be fixable, also its possible it could just be the switch that needs cleaned.

[@MrEwool]

Nice one 👍

[@BuyitFixit]

Thanks!

[@jonnyduncan7056]

Dean Doherty- Donegal Ireland who streams on YT says Millwaukee gear is terrible

[@stestar09]

Working on 1 for a mate of my dads , same problem as your1 , the led lights up , & motor doesn't turn . The thing looks like new & has only been bought for jobs around the home , so he's had it longer than the warranty & didn't register it for the extended 1 . Disgraceful how its failed so quick , done 2 small projects with it & kaput !! Tested the switch & both connections work , the motor wires gain 20.6 v when switched, any idea if its the motor board or the battery board ?

[@BuyitFixit]

Unfortunately I can't say without testing components. First thing I would do is check the MOSFETS for shorts with a test meter, although I did have a couple of people mention about failed ribbon cables so perhaps that might be something else worth inspecting?

[@mariusdideriksen8305]

great video! I was wondering if i could have your input on the common issue with the fms305 mitre saw? The motor brake system stops working and the blade keeps spinning. Im thinking of fixing it myself since my warranty has run out and the electronics assembly is almost as much as a new saw. Im not exactly sure where to start or what to look for in the circuits. Any specific type of component i need to look for? Your help would be very much appreciated!

[@BuyitFixit]

I think I've got the guts out of one that someone sent me. The mosfet on the braking board had failed but it had also backfed 18v into the microcontroller. The motor would not spin up at and the microcontroller just got hot when you pulled the trigger. By sounds of it at least yours still spins so if it's the same as this there is a separate brake board with two mosfets on and I think wired to two large resistors. I'd be checking the mosfets on the braking board first. Hope that helps 🙂

[@BodgeGuy]

Hi, I think I managed to fix my nail gun off the back of one of your vids and some research. Now onto my circular saw. The mosfet are oriented differently in my later model. Could you let me know your preferred mosfet supplier? I think ones gone, but not 100% sure 😅

[@BuyitFixit]

Hi I had to double check but it was digikey that I ordered the mosfets for the tools that I repaired. If you can find a pinout of the mosfets check the GATE pin, between the other pins as that is usually a good indication of a shorted mosfet. Oh and well done on repairing your nail gun 👍

[@wherami]

wonderful fix!

[@BuyitFixit]

Thanks J S!

[@Landesign58]

They don’t sell them because they don’t want you to repair them yourself!

[@BuyitFixit]

Yes, like most companies these days they would rather have you buy a new one.

[@thetraindriver01]

Nice follow up vid, with a full fix, sorted 👌

[@BuyitFixit]

Thanks 👍

[@tristanroberts1645]

That was a good fix 👍

[@BuyitFixit]

Thanks 👍

[@RevilO5011]

Hi mate, I have a similar problem with my CCS55 (its not spinning) I have checked the switch, checked that voltage is reaching the stator pcb when the switch is activated and battery connected, checked all fets, diodes, resistors and capacitors** on the stator board and found nothing. There is epoxy over the battery control board like you found in your video so i can't inspect it easily. Is there something i might be missing? Id appreciate the help. **I did notice one tiny capacitor over near the ribbon connector on the stator board that wouldn't give any reading, but perhaps this is because its in circuit? Again, any help would be appreciated.

[@BuyitFixit]

Does the LED light up? Can you feel any heat when holding down the trigger on the potted board? Have you checked the mosfets?

[@RevilO5011]

@@BuyitFixit I'll check regarding heat but I have checked the MOSFETs and the LED does light up when the safety is triggered

[@BuyitFixit]

I had a large angle grinder to that, and another saw. Unfortunately it was the microcontroller / BLDC pre-driver chip had failed, and you cant get them or get the program to program into one if you could.

[@RevilO5011]

@@BuyitFixit if it does turn out to be that then that would be a shame, I'll try and get the resin off the potted board as a last ditch attempt before giving up. Appreciate the help!

[@RevilO5011]

@@BuyitFixit no chance you have a schematic of the saw PCB?

[@BodgeGuy]

Hi, do you carry out repairs or just repair on the channel?

[@BuyitFixit]

Hi Stu, unfortunately I just do stuff on the channel, I'm not a repair business and just do it as a hobby. I still may be able to help you via messages or something if you wish to have a go yourself?

[@BodgeGuy]

@@BuyitFixit Thank you. Only had saw 30 months. But told they wont accept 3 year warranty as I didn't register it. Not sure if that's legally right. Maybe a side video on tool warranty rights would be good. Haven't seen one. Also my multi tool is melting my battery cases. So maybe I'll try to fix. Great videos!

[@BuyitFixit]

@@BodgeGuy Thanks Stu. I did have a run in with a manufacturer once over a warranty issue, and I spoke to citizens advice (not sure if you're in the UK). They told me that the manufacturers are not even legally obliged to give a 12 month warranty if I remember correctly and its totally down to their discretion.

[@MrTorch8]

Nicely done!

[@BuyitFixit]

Thanks Jacob!

[@ferencszabo3504]

I got the situation with a brushed B&D saw that the PIC microcontroller is gone bad, but thank God it only controlled a MOSFET driver, so I've feed the 3.3 V to the driver and voila, it's working! 😊 Ok it had the INA chip for current feedback, but hey I just know to have to stop when I bump into an obstacle!

[@BuyitFixit]

Nice 👍hopefully the battery management is done in the battery and not the tool as Milwaukee does.

[@richardmahoney6877]

do you have a source for these control boards?

[@BuyitFixit]

Unfortunately not and it seems a quite common problem. I had thought of designing my own, but haven't had the time to start looking at that yet.

I have same trouble only on 1 year old saw and it’s out of warranty , I’m trouble finding the driver spare part :(

[@BuyitFixit]

Unfortunately Milwaukee doesn't sell the driver as a part, it's the whole motor and electronics all in one lump and it was quite expensive from what I remember.

@@BuyitFixit that’s a shame :(

[@eugenebuster5417]

Do u know where I could get that part from

[@BuyitFixit]

Unfortunately only a used unit. Milwaukee only sell the whole motor assembly as a unit and not separate bits 🙁

[@eugenebuster5417]

Thank you

[@samsungsexy7164]

❤ to see you efforts fixing Milwaukees @ chip level 👌

[@BuyitFixit]

Thanks! I've fixed quite a few items like that including the Milwaukee vibrating multitool 🙂

[@homegrownpyrotechnics70-30]

Nice fix! Mine was just the switch contacts were dirty.

[@BuyitFixit]

Nice, well done on fixing it 👍