Rack Motion Error

6 years agoReply by

It sounds like the rack present sensor is not detecting your racks and that is why the chain does not move. You did not specify which racks you are using but typically this happens with the blue mini vial racks. Often times a minor adjustment of the potentiometer on the board itself can fix the problem. In order to do this you need a DVM, a small flat blade screwdriver, and a little dexterity to get into the sensor with both your test lead and the screwdriver. If you are up to it let me lnow and I'll give you further instructions. Don

6 years agoReply by

It is indeed happening with the mini vial racks. Further instruction would be greatly appreciated.

Joel

6 years agoReply by

Joel, Does it also do it with the Maxi racks? Don

6 years agoReply by

I don't know-I only use the small vials. I can check on that today.

6 years agoReply by

The chains don't move large vial racks either.

6 years agoReply by

Joel, Then your problem is the rack sensor has either failed or needs a little tweaking. Do you have a DVM and a small flat blade screwdriver because that is what is needed to determine if the sensor has failed or if it just needs a little adjustment?

Don

6 years agoReply by

Yes, I have those available.

6 years agoReply by

Joel, note where there is an opening down in the lower right back corner wall of the sample changer bed. You will probably need a flashlight to see where the sensor is located and then straight up from there you should see an opening with a black test point and small potentiometer. Insert the positive meter lead into the test point and the ground lead into one of the ground leads on the main board assembly. Note the reading and then manually slide either rack to the front of the changer bed and see what happens to the voltage reading. If memory serves me correctly, the voltage should go from around 5 volts DC down to about 1 to 1.5 volts DC. If the voltage does not move with one type of rack at all then check the other rack too in order to see if the sensor is just dead. Chances are that it will just need a little tweaking. I know that you may be thinking that no one has adjusted the sensor at all so why should it have changed somehow? No good reason that I can give you because I never figured out why that could happen in the almost 30 years that I worked on all of the Beckman benchtop LS counters that used the same sample changer bed sensor setup. It just happens right along with the sensor failing for no reason either. The other thing to look for is has the sensor alignment been shifted by someone poking or cleaning the changer bed such that it is not pointing forward and slightly to the left. That has happened to me too. Give it a shot and let me know.

Don

6 years agoReply by

Thanks Don. I won't be able to try it until the weekend, but I will let you know what happens.