I have this blender that won't spin when switched on, the leds turn on tough.
I managed to take it apart:https://imgur.com/a/eMSSXm4
From the mains power (!caution is used all times!) we have:
- on line going to a micro-switch that I shunted (it's purpuse is to make sure the bowl is secure on top of the blender).
- a main PCB that has a few resistors, cap (0.1uF), triac (BTB06) , diode (DB3), turn knob ( has 7 states: off, CCW - pulse (has spring and turns back to off if let go) + 5 speeds (all CW) )
- a secondary PCB that has 3 LEDs, 2 resistors and an IC that seems to read MDD M7
My theoretical and practical background is limited to low voltage DC circuits mostly but I do understand the dangers of working with mains voltage and would like to further expand my knowledge in this area.
I was thinking of first ruling out that the motor is not faulty. Where should I probe with my DMM on it? Should I be measuring continuity(resistance) along the coils or try to measure AC with it ON as so to make sure it's getting power? ( Yes, dangerous if not careful)
Is there an practical way to test that the triac or diode ( based on the datasheet I see it's not a simple zener diode ) is ok?
Taking parts off the PCB is not an issue if there is a test rig I can create to make sure components are not faulty. I also have an oscope if there is a need for it.
I was lucky and managed to get locally a DB3 diac and a BTB12 triac (i'm guessing the higher amp rating shouldn't influence negatively). After soldering them on there was no change, no motor spin.
I managed to get my hand on an identical, working blender. I then cut the wires from it's controller and hooked it up to my motor and there was a small buzzing from the PCB but no motor spin (I only had it on for max 2 sec as i didn't want to burn anything ). When I hooked up the controller that I am reparing to the working blenders motor it spun up and worked normally. This way I was able to pinpoint that it's my motor that is faulty.
After a little research I found out that it's a universal motor and thus can be powered with my DC bench supply (something i'm more familiar with :P).
If I hooked my bench supply's leads (polarity didn't matter) to:
White lead and brush guide closest to me ( 1 and 2 pic ) the motor would spin.
White lead and brush guide furthest to me it would arc (short).
Blue lead and either brush guide nothing would happen.
Am I safe to assume that the stator winding that is on the blue side lead has failed?
If so, what are my options?