noob help: New Anet3d (China) printer shows "def" temperatures

Dear all,
excuse a newbie for crying out for help, but I tried searching this forum and google and did not succeed.

I just got my Chinese Anet3d A8 printer kit delivered (my very first, very cheap to start with), and Anet is kind enough to post a video of first checks of the electronics in YouTube (https://youtu.be/6W2GuwgPIkI) which I followed.

All seemed fine (all motors turning as expected), except the temperature of hot end and bed are shown as about -50°C for a fraction of a second and then displaying "def".

I took my multimeter and measured about 110kOhms at 21°C room temp. As I learned I had to expect a value <100kOhms, as the thermistors usually are at 100kOhms at 0°C and resistance sinks with increasing temperature.

So: Are my thermistors bad? Should I try to return the package? Is there any chance to find out what the board/firmware expects the thermistors to be, so I can replace them by the right ones?

Thank you very much
Rainer


Model (according to package label): Anet A8-B Prusa i3 (Didn't look very alike the Prusa i3 models here at reprap.org)
(according to display at boot): Omni

Edited 1 time(s). Last edit at 04/29/2016 04:57PM by rainerunsinn.

I have the same issue. I followed this video too. When the printer is just loaded tempetature of hot end is shown as 26 C° and -51 C° for heated bed, but next second both of values are changed to "def". When I plugs printer to computer with Repetier this message is shown in log: "heated bed: temp sensor defect".

Also when I try to Preheat PLA (like on this video [youtu.be]) nothing happens. Leds on the board do not turn on and there are no voltage on hot end and heated bed.

Edited 3 time(s). Last edit at 04/29/2016 05:41PM by pilyugin.

Nice videos to help test and assemble yet an other piece of junk

Edited 1 time(s). Last edit at 04/30/2016 05:16AM by MKSA.

@pilyugin
I found it: the plug from the thermistor wires is somehow bent: I pulled the wires from it and stuck them directly into the male plug - worked with next power-up.

@MKSA
I know it is cheap crap, but I wanted to spend as little money as possible for the first walking attempts. Your comment wasn't helpful at all for the question.

Rainer

@rainerunsinn Yes, I found it too. One of the thermistor legs was broken. After soldering it works fine.