I don't see any sign of a bridge on the AC/DC power board (bottom).
Unless D5 to D8 on the other board?
Off load the motor should turn even with 12vdc
Max.

 

Do you mean, you can't see how the DC output is connected to the AC input? sorry, i don't follow the context your saying it in :/

 

I will attempt attaching this motor to a 12v source, thats as high as i have though. Not sure if it will spin.

Off load, Motor 54rev/volt!
I see the AC input and the cap on one board and the bridge on the other?
Max.

 

Its the same board, showing the front and back of it.

 

OK, got it.
It would then appear to be some kind of PWM control of the motor as Q1 appears to feed the motor output socket.
Do you have a meter?
Max.

 

The motor is confirmed to work. 12v spins the motor very slowly, but its spinning. That is one more thing to write off. I also know that AC power gets to the board, but DC powere is not leaving the board. So, some component is bad....

 

Q1 does indeed feed the motor output connector. Is there any way to test this mosfet (what i assume to be a mosfet anyway).

 

Q1, from its markings is shown as a N-Channel MOSFET. The only way to test this would be to feed AC power and take a multimeter to the mosfet isn't it?

 

We can probabally assume the bridge is OK as you lit up your jumper from the cap!
The only other power device IS the mosfet so it is a likely suspect.
You could measure the voltage on the gate and drain WRT the source, remember its 240vdc.
Max.

 

Okay, so with this powered on and the vacuum in a state where i would expect the motor to be on, what would you expect to see with the multimeter set to DC 600v with the + lead on the drain and the -lead on the gate? roughly around 230v?

 

Depending on the part No of the mosfet I would expect to see at least 10v on the gate and anything over 50vdc on the drain, WRT the source.
There must be means of changing the rpm somewhere.
Max.

 

Let me clarify, WRT means with reference to? Meaning that the COM port on my multimeter goes on the source and then the + lead to the drain and then to the gate, right?

 

At first glance, the MOSFET appears to be a logic level one, the gate threshold is typically 3v.

http://www.st.com/content/ccc/resou...df/jcr:content/translations/en.DM00123510.pdf

 

Correct, With ref to the source.
I looked at the boards again and I only see a motor out and AC in, it is a little puzzling why the Mosfet, IOW implied variable speed?
Ok but there should be some mean low voltage on the gate.
Max.

 

I don't see logic level on the spec sheet, it says automotive use?
That is gate threshold v.
Max.

 

Yeah, my bad sorry.

So with the hoover configured to power the motor, and WRT source i read 330VDC on the drain. Now, am i correct in thinking that there could be 2 different reasons for this being so high, source could be negative OR drain is 330v when it should be 240v?

 

Mosfet is not conducting or turned on.
240v AC when rectified and smoothed is high as 339vdc
Max.

 

240v AC when rectified and smoothed is high as 339vdc

Thank you for pointing this out, this is probably basic electronics knowledge for you, but i didn't have a clue on that simple fact. Thank you!

Now i need to troubleshoot why the mosfet is not conducting. I need to hit the bed now, so tomorrow i will get a reading of the gate WRT source. From that datasheet, what would you expect the gate voltage be to turn the mosfet on? I'm thinking that if Vgs is below 4V then i need to troubleshoot why the mosfet is not turning on, if its above 4v and not allowing the flow from Drain to Source then the mosfet is bad, right?

 

See what the voltages show, I am wondering due to the seemingly absence of external control of the mosfet circuit, if it is just a slow start circuit to avoid the full motor voltage at switch on?
Max.

 

During tests yesterday i had the hoover running for over 30 seconds a timer and it never started that motor at any point. I did think it may have been a delayed ramp up.