Hi, I replaced: the engine, the sensor alarm harness, the little cat sensor, the circuitboard. The only thing left is the power switch. Nothing changed the problem: the yellow light goes solid on “Cycling/In Use” and after a period of time it goes on blinking red “Sensor/Timing”. I tried turn the sensor knob multiple times in one and two turns at a time and nothing. Any hints on how to solve this? The power switch seems to be the only part where the problem originates as the other parts are all new. Any kind of reset sequence? Thank you!
1 Like
Hi @marioflecha and welcome to our forum.
We are sorry to hear about the problem with Litter Robot 2.
Red blinking light means that cat switch was activated for more than two minutes.
You mentioned that you installed a new one. You should check if the new one is working and that it is wired up properly.
When you press the entrance step of the robot, you should hear the cat switch clicking.
Can you take a photo of how the sensor is wired up? Maybe you switched the wires?
In the end, although you already tried that, try to decrease sensitivity of the sensor by turning the foot knob to the right.
Let us know if this helps.
Hi , thank you for your reply. I read the guides and followed the instructions several times for the cat sensor. I became quite familiar with all those parts. Nevertheless, from your perspective, you are making the best assumptions. I replaced the engine around 4-5 years ago. We have the Liter-robot for 12 years! And it still was rocking (great design). Following the logic of the troubleshooting guides I came to replace the cat sensor, and tried what I could with the sensor knob; for no avail. Once the problem persisted I moved to replace the circuitboard and, again, the problem persisted. I replaced the sensor harness and nothing changed. Then I replaced the engine; and nothing. Finally, my last thing to replace is the power switch (I am assuming that the pinch sensor wouldn’t cause the behaviour . Did you see the little videos I sent previously? I will take detailed pictures of the wiring and send them to you. Perhaps I did something wrong there (I tried not to, but one never knows). I hope you can help us. This machine is too good to throw in the garbage. If we find the culprit is it possible to return the parts that I bought trying to fix it? Cheers!
1 Like
Hi @marioflecha,
Thank you for your reply.
Yes, I saw the video.
One more thing that you could test. Did you test if the safety line switch is working?
Hi, The safety line is the pinch sensor? How do I test it? I pulled the cable and nothing happened. The device is locked on the yellow and then red light blinking. All wiring is new. The little box with the pinch sensor was a bit dirt. I will film each part to show the wiring connections and the pinch sensor. Thank you for helping us. 
The wiring video and photos:
1 Like
Hi @marioflecha and sorry for late reply.
See this:
Also, try to move the connection on the cat micro switch and see if anything changes:
1 Like
Hi there, I will try and let you know. Thank you!
1 Like
Howdy! I changed the connector position in the cat sensor but nothing changed. I tried multiple positions trying to tune the alarms sensitivity but nothing. I can put the other cat sensor (the old one) and the old circuitboard to see it changes something. Other than that there are 3 items to consider: the power switch; the cat pinch sensor (it clicks when the cable is pulled); the AC/DC converter (nevertheless some current is passing because the yellow light and the blinking red happen snd the engine turns a tinny bit and makes a little sound).
1 Like
Hi, I will try and let you know. I did it before but it is worthy to try and ensure that it was tried. If you had to pick on which one is the problem what component would you choose from these 3:
Power Switch
Pinch Sensor
AC/DC converter
1 Like
Pinch Sensor 
Ok! If the tests with the circuitboard doesn’t work I will order a pinch sensor and 
I hope I can return the items that I bought but didn’t resolve the problem (now I I have a replacement for each of those components, which might be a good idea to keep).
I let you know the findings. Thank you so much. Have a great day!
1 Like
Hi # , is the pinch sensor the same as the cat sensor? I say that because I couldn’t find one when I searched. They have the metal part but not the sensor. I noticed that some Litter-robot II don’t use the sensor (like the cat sensor one). They use only the metal plate where the connectors are plugged directly.
Thank you!
1 Like
Hi @marioflecha .
I think it is.
See this part: Litter-Robot 2 Safety Line Switch - RobotShop
Can you locate it and see how it is connected?
Hi, I will take pictures. Thank you!
1 Like
Hi,
I replaced the safety sensor with the new and the old cat sensors and nothing changed (they are the same). I tested with an the AC/DC converter like the original and nothing changed. The only remaining part to be replaced is the power switch. All the original electronic parts were replaced (i.e. cat sensor; circuitboard; sensor harness; engine) and tested several times. Other than that it is only the plastic material. What intrigues me is how can the problem persist with all electronic parts new and the connections verified several times based on pictures and guides. The only component left to replace is the power switch. Any ideas?
Thank you!
1 Like
Hi @marioflecha
I don’t believe that the problem is power switch. If it isn’t working, you wouldn’t have the power on the robot at all.
I think you should have a look at the safety line switch. Have a look where it is connected and what it is activating.
Thank you.
Hi! I agree with you but here is what I’ve done:
I have two cat sensor switches (the new one that I bought to replace the old and the old one). The new one didn’t solve the problem, which persisted with both switches (the old and knew). I replaced the safety switch and tested with both of the aforementioned switches for no avail. There is no other type of switch for sale at Robotshop. Our Litter-robot uses a switch and not the little metal piece for the safety sensor. I am able to return the new engine for a partial refund but the other parts cannot be returned because they are past 30 days.
I still can buy and try the little metal piece (if it fits in our Litter-robot). Electricity is passing through the power switch in all test cases, but is it the right amount for things to work? My guess is yes, but what else is left when everything else was replaced and tested and the problem remains the same? I tested the AC/DC power plug with one that had the same specs and electricity was reaching the Litter-robot. Every time I turn the power switch on the engine moves a tiny little bit and then the yellow light goes on; and a bit later it goes to blinking red.
If the new engine or the new circuitboard or the new cat sensor or the sensor harness have a problem like the old parts that they were supposed to replace we could have a situation like this, where even with all the parts replaced, verified and tested the original problem remains (it would be very unlucky but possible). There is no reset key for the circuitboard, is there? My last attempt, and hope, is the metal plate for the safety alarm.
Thank you!
1 Like
Hi @marioflecha ,
Problem sounds like a mechanical issue. Either cat switch or safety line switch is activated all the time. Can you try and bypass the safety line switch?
Regarding the metal pieces. You think of these Litter-Robot 3 Open Air Anti-Pinch Pins (2pk) - RobotShop ? As far as I know, these exist in Litter Robot 3 but not in Litter Robot 2.
Thank you.