Fridge Samsung RS2530BBP

[Fridger]

Hi All, Samsung damper is apparently closed, freezer fine but fridge around 50'sF. I took the damper out, opened up, no lock-ups found, removed motor so gears no engaged and bench tested the actual small motor by 12V DC, it was jerking a bit when DC applied but not spinning, it was spinning freely  only by hand when power off and when power on, it was holding but I could spin it with more force and could feel the magnetic field acting in steps, no mechanic obstruction. I couldn't cross and find these little motors on the web but I feel it may be powered by different voltage then DC. Perhaps some pulse if not AC generated by the PC board but I am just guessing so if anyone ever played with this please let me know. I tend always go to detail since it is a hobby to me as well. Didn't check thermistors voltage drop yet but tonight I'll do it after smacking all back together.

Perhaps the circuit on the PC board has an issue not making the proper current/voltage type so it can not spin and it maybe originally making by factory less than 12 Volts. All 3 thermistors checked OK at ambient room temp. and in Icy water and all are type sealed.

Other fridge Kenmore similar to this one some time ago have shown good thermistors after test but under the load the freezer-one failed apparently making fridge running non stop. I just replaced the thermistor and it runs good ever-since. Didn't check voltage drop at that time so who knows but apparently basic test using ice water is not enough in some cases especially where freezer goes to bellow 0F.

Thanks for attention.......................

[WOOKIE]

If I am not mistaken it is a stepper motor that is controlled by the micon which provides the 12 volt dc.  It is rocking back and forth because it also needs a signal to tell it which direction to move. 

Edited May 29, 2020 by WOOKIE
Or it could have multiple windings. one winding causes to step one direction . the other to step the other direction.

[Fridger]

Thanks so much, I just came back looking at that issue and hooked an AC power adapter 5V AC to the motor and it spins. I saw 5V DC regulator 7805 nearby but nothing what would alternate it except row of resistors and electrolytic cap. Much higher up on other side of the board are small transistor so tomorrow I'll take the board out to trace and cross if any of these components are related to the motor. Other Board from some french-door fridge has near the damper connector 2 small high switching transistors so they apparently using this technology on these dampers but not always I guess. The smaller the motor, AC is possibly needed for this function I guess. Yes, I have 2 windings for each direction. This is apparently an issue where the MOBO is recommended to replace but I'll do anything possible to avoid it since I got so far, never give-up. It still may be thermistor related which tells the main chip to trigger alternative power for the damper and if thermistor sleeps then nothing can happen or very little. I tested V drop on each thermistor and it was good - 1V-4V but it was running shortly with about 60F inside but days before it was running all day and 55F in fridge and return line icing, air flow in fridge restricted, freezer works good. Damper was closed when I took it a part first time after running it overnight.

Thanks again. 

[Fridger]

All is well by now, replacing all 4 or 5 electrolytic caps on the main-board revived the damper's stepper motor circuit to run. Still had to change the freezer thermistor to make the fridge cycling on and off otherwise it was running all the time like the other mentioned fridge. Double issue but I know for now that these thermistors fail but do not show when tested without and under load at least in my last 2 fridge cases.