MC fan running full speed (solved/repaired)

Thank hybride for your details!
David is proving to be very helpful!

Good work! Thanks for sharing this.

See link for lead up to this: http://visforvoltage.org/forum/13939-mc-fan-running-full-speed

My thanks to David an hybride for sharing their knowledge here too.

I bought short time ago a VX with some problems and after I thought to have solved them I made a longer testride.
The temp warning lamp in the dashboard came up and the controller switched off. I could get a "go" again but it was running only slowly driven a short time and than switched off again.
Now I realized that the controller fan wasn't working at any time. Nothing.
I could manage after a break to get slowly back to my home with the VX.
I checked the fan itself at home but it was running from 1,5 to 12V with 0,6 to 3,5 Amps. Was a bit noisy at work so I will exchange the fan now too.
Now I have ordered the PS2801 and a FDS5672 which has lower Ron as the FDS5670. Hope it will stay a bit cooler on the board.
I wanted to remark this here.
I will report if it works or not when I have exchanged the parts.

greetings

Klaus

I took the MC board out of the VX today and made some photos.

I'm missing R22 ? and was astonished to find a resistor clued on top of the Fet Q2 with isolation paint ?
Isolation paint over Q2 has about 1mm !of thickness.
Its not as brown as it looks at the pic.
But everything around U4 seems to be like it should be ?
Has someone here a photo for me how it should look like around Q2 at a good working MC ?
Should R22 be there and no clued resistor on top ? I think so ?

best regards

Klaus

Hi hybride,
yes, the fan doesn't work, gets no power anymore.
The fan itself works well, I have checked it with a power supply.
I found an old photo from Mik here where a small R22 ist on its planed place at the board. So that was one of the first board versions ?
I did measure the value of the resistor on top with 500 Ohms . Is that not a bit to low resistance ?
Is that the pull up resistor to + 12V for the gate ? So maybe it will get a bit hot with 12V and 1kOhm or still hoter with 500 Ohms.
I removed the resistor on top already because I want to exchange all parts.
I have orded now 1kOhm for R22, case 1206 with 0,25 Watts. So its not a good idea to solder it at its marked place at the board ?
I am a bit confused now.
Do I need a resistor with 0,5 Watts or more and do I need 1kOhm or 500 Ohms ? With 500 Ohms I see some danger for the opto-coupler coming up because it has to switch 25mA.

Many greetings

Klaus

Today we exchanged the 3 mentioned components. The fan workes now again like it should work. Finally I took for R22 1k5 and 0,5Watts, found a nice free place directly on the board to solder it and not on top of the Fet. I took the FDS5672.The Value of R24 could be measured on the board and was ok, so it wasn't exchanged.

Greetings and thanks for the diagram to hybride

Klaus

Hi There

I have a similar problem to this.

I got the high temp HS hot error and discovered my MC fan was seized. I bought a replacement from the parts place in Poland, fitted it and now I've discovered there is no power to it.

Can you give more info on the repair above or has anyone tired bringing am alternative 12 V supply to the fan?

Thanks

Barry

Hello

first check please if the 12V are present on the board and if the fan is running when you connect it directly to a power supply with 12V or lower voltage.
If that's ok than may be only the components from the here already posted wiring diagram faulty.This are only a few possible components !
Please check than this components and/or exchange them again.

many regards

Klaus

Thanks Klaus

I dont have the MC board out yet.

I powered the new fan with 12V and it works fine.

I dont know yet where the 12V rail on the MC board are yet.

It looks like I will need to replace the components.

Regards

Barry

Barry, was the controller hot or cold when you checked for voltage at the fan?

I am only aware of the M/C fan running on mine when it gets warm, so there might not be any voltage to read at the fan connector if the M/C is stone cold.

Alan

Independant from if the controller ist cold or not, if you have a "go" and could start going with the scooter the fan should run already but with low rpm. Its not easy than to hear it but you can feel the airflow with your hand in front of the rear wheel. If you than want to start and pull up the throttle you should hear it loudly with its increasing rpm.

many greetings

Klaus

After I installed new fan I took it for a test drive about 20kms and about 15kms along I got the fault. As I was near a petrol station I drove in and blew compressed air over the fan and the error disappeared. I'm confident its not working, perhaps when the fan seized the corresponding dc short caused the circuit on the mc board to be damaged.

I've ordered the mosfet, opto isolatar and the resistor.

Does the MC controller come out from the fan side?

Thanks

Barry

After I installed new fan I took it for a test drive about 20kms and about 15kms along I got the fault. As I was near a petrol station I drove in and blew compressed air over the fan and the error disappeared. I'm confident its not working, perhaps when the fan seized the corresponding dc short caused the circuit on the mc board to be damaged.

I've ordered the mosfet, opto isolatar and the resistor.

Does the MC controller come out from the fan side?

Thanks

Barry

No Barry,
the MC is mounted with screws in the battery box and is dismounted from there.You have to put out first the rear battery pack .

Hi Guys

I've confirmed that the circuit with Q2 has blown probably when the HS fan seized.

So I'm not keen on taking out the MC board to try to solder surface mount components on it.

I prefer the option of powering the fan with 12V DC directly in an all on the time mode.

Can anyone advise on an easy to access point on top of the MC board where I can get a good 12V feed?

Thanks in advance

Barry