Author Topic: DC40 Brushroll Motor Failure or Not? Baffled... (Read 9786 times)

macman · « **on:** March 08, 2019, 01:21:59 pm »

Hoping someone can point me in the right direction with this one, which has got me completely stumped.
Machine came in yesterday with a report of 'an electrical burning smell, then the brushroll wouldn't turn'. Now, call me Sherlock, but I deduced a brushroll motor burn-out. By coincidence, I had another DC40 in for a service which has a working brushroll, so I swapped the heads over. The 'good' head wouldn't run on the bad machine either, the 'bad' head still wouldn't run on the good machine.
So, I assumed PCB burn out or yolk loom failure...
I then stripped down the bad head to check the motor and it didn't look in too bad condition, no obvious sign of burn- out like I've often seen on DC25's. Then tested the voltage at the head connector and got about 310V DC. So seems that it's not the yolk loom or PCB then. I then realised that I was getting 310V regardless of whether the machine was reclined or not, so possible actuator fault, reset switch failure?
I'm going to look at the PCB next, but if it's supplying 310V then surely it can't be the issue? Which rules out the motor blowing and taking the PCB out with it, which was my next thought.
I've double-checked all the above again this morning in case I'd missed something obvious. But exactly the same result.
Should I also check the brushroll motor for resistance across the brush terminals, and if so, what reading should I be getting please?

ryevac · « **Reply #1 on:** March 08, 2019, 04:07:56 pm »

310v dc present as you say macman, but that is off load voltage.
part strip the head, reattach and turn machine on, measure voltage on motor terminals and i suspect it wont be 310v.

Possibly motor has failed, and taken control pcb with it ?
always a hard fault to trace with a red herring in there, ending up with chicken and egg situation

MVacs · « **Reply #2 on:** March 09, 2019, 04:29:36 pm »

Quote from: ryevac on March 08, 2019, 04:07:56 pm

Possibly motor has failed, and taken control pcb with it ?

We have been seeing this recently. We have replaced the odd PCB and its come back a week or two later with the PCB gone again. Now if they need a PCB or a motor they get both.

macman · « **Reply #3 on:** March 10, 2019, 06:01:34 pm »

I was hoping not to have to delve into the innards to get at the PCB: it looks like a nightmare job, but it seems like there is no other option. Is there a step-by-step somewhere that covers this topic please?
What I still can't work out is why I'm getting the same 310V DC reading at the cleaner head connector with the machine both upright and reclined?

MVacs · « **Reply #4 on:** March 10, 2019, 06:08:05 pm »

Bekos strip down topic in the stickies is as comprehensive as you need. No great pain getting to the PCB I think......

macman · « **Reply #5 on:** March 10, 2019, 06:11:10 pm »

Thanks, not quite clear from that if I need to remove the entire yolk assembly first to access the PCB?
Are these available used or should I replace with new?

MVacs · « **Reply #6 on:** March 10, 2019, 06:13:40 pm »

We always use new, there are two different ones IIRC.

About the complexity of the strip down I will ask our chap tomorrow.

macman · « **Reply #7 on:** March 11, 2019, 11:23:45 am »

Thanks, much appreciated. Mine is the ERP model, with the red slider switch on the head.

macman · « **Reply #8 on:** March 11, 2019, 04:14:01 pm »

No worries, I had a look at Sam's stripdown pics, then dived in. Not quite as tricky as I'd feared, the yoke and loom don't need to be touched. Just 6 screws to come out in total. The PCB has definitely blown, leaving a lovely big scorch mark. I'll check the pricing with Claire.

macman · « **Reply #9 on:** March 11, 2019, 05:33:45 pm »

PS: am I dreaming this, or was the problem with the breaking yoke loom confined to Mk1 models only, i.e. it does not affect the later ERP Mk2 models?
Until 3 weeks ago, I'd never seen a DC40 or DC50, now I've had 4 come in in rapid succession. The only good thing I can say about them is that they're nice and light...

Parwaz7862 · « **Reply #10 on:** March 12, 2019, 12:41:31 am »

Quote from: macman on March 11, 2019, 05:33:45 pm

PS: am I dreaming this, or was the problem with the breaking yoke loom confined to Mk1 models only, i.e. it does not affect the later ERP Mk2 models?
Until 3 weeks ago, I'd never seen a DC40 or DC50, now I've had 4 come in in rapid succession. The only good thing I can say about them is that they're nice and light...

I've never heard of an ERP/ Mk2 model with a broken loom yet and they were launched in 2014

You only just got these for the first time? Make sure you scrape out the fluff from the bellows of the active base plate and have a quick play. It will be the most powerful Dyson you've ever used!

macman · « **Reply #11 on:** March 13, 2019, 06:54:52 pm »

I'm beginning to hate these small ball models with a passion. Why? As Parwaz says, the bellows are always full of cak, which needs to be tediously scraped out with a DC04 switch removal tool. The red slider switch on the ERP versions is always seized solid, and customers' don't have a clue what it's for anyway. The cyclone clogs up within minutes around the slotted bit in the middle, and the brushroll motors are the same short-life units as the DC25.
They may indeed be powerful when in full working order, but I've yet to see one that will be in that state for very long.

ryevac · « **Reply #12 on:** March 13, 2019, 07:56:44 pm »

As previously mentioned, i refuse to work on some newer models.
The dc25 / 40 head motor hasn't a short life i don't think, just luck on how long it lasts with average use ?

I must admit i have replaced more head motors on the dc40's than i have on the dc25 models, so probably down to motor drive circuit design that was introduced on the dc40 ?

Parwaz7862 · « **Reply #13 on:** March 13, 2019, 10:45:47 pm »

Quote from: macman on March 13, 2019, 06:54:52 pm

I'm beginning to hate these small ball models with a passion. Why? As Parwaz says, the bellows are always full of cak, which needs to be tediously scraped out with a DC04 switch removal tool. The red slider switch on the ERP versions is always seized solid, and customers' don't have a clue what it's for anyway. The cyclone clogs up within minutes around the slotted bit in the middle, and the brushroll motors are the same short-life units as the DC25.
They may indeed be powerful when in full working order, but I've yet to see one that will be in that state for very long.

The small ball is weak, it's the full sized ERP DC41/55 and the medium 40 as well that are fantastic! I don't swear by them for no reason you know

Oh and the new light ball is even better than these

"DC04 switch removal tool" Haha! But on a serious note, you can use a toothpick even or any flatblade

Parwaz7862 · « **Reply #14 on:** March 13, 2019, 10:47:19 pm »

Quote from: ryevac on March 13, 2019, 07:56:44 pm

As previously mentioned, i refuse to work on some newer models.
The dc25 / 40 head motor hasn't a short life i don't think, just luck on how long it lasts with average use ?

I must admit i have replaced more head motors on the dc40's than i have on the dc25 models, so probably down to motor drive circuit design that was introduced on the dc40 ?

Cos the early DC40s had the crappy DC24 brush motor for some reason :/ the ERP ones had the DC25 sized one (the DC41 always had it anyway) and they've improved them

I've yet to see a blown up one and they're 5 years old this year