Discussion Category:  Centrifuge

"Lid" Error Message

Hey all,

I just got my machine running a few minutes ago after a minor circuit breaker repair. For some reason I keep getting the LID error after running the machine at 3200RPM for a couple minutes. The lid is well secured as far as I can tell. 

Any ideas what the reason might be for this message?

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Asked by

mrwright
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avatar placemarkReply by
medphysteo

I don't know what to say to that. By unplugging J1 from the board you have electrically isolated both latches from the rest of the machine. Unless there is a wire inside one of the latches that is pinched so badly that the insulation is broken and a strand of wire is making contact with the housing, while at the same time the same thing has happened with the neutral side of the power line somewhere inside the machine casing.

On my machine both latches have a tab attached to the emergency release arm pivot, where a ground wire could be attached (I'll send a picture to your gmail). Does yours have a wire at either location? The insulation would either be green, or green with a yellow stripe spiralling around it. If there is you could pull it off and see if that changes anything.

My only suggestion other than that is to dismantle the whole machine again and make sure there are no pinched wires anywhere. Sorry to make you go there again, but what you're describing shouldn't be physically possible.

Jeff

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avatar placemarkReply by
mrwright

I think I've been measuring the wrong connectors. I've been measuring the connector thats soldered to the circuit board at J1. From what it sounds like, I should be measuring the plug that houses the Violet, Red, Black and White wires that plug into J1. 

With machine unplugged, and lid open I get the "OL" reading when touching the multimeter to the Violet and Red wires (1 & 2).

With the lid closed, I get some resistance when touching those two wires. I see the display jump to 0.20k ohms before dropping back down to 0.00.

I emailed a few photos for reference.

-Chris

 

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avatar placemarkReply by
medphysteo

I see where I may have allowed some confusion here as well. In the service manual you'll see references at the top of p.38 to J1, and J/P9 and 12. On the circuit board you'll see connectors labelled as J1, J9, J12, etc. The connector on the board is J1 (for example) and the plug that it receives is P1 (Jack and Plug 1). Usually the J/P labelling is reserved for in-line hanging or mounted interconnects, like those on the latch assemblies themselves (J/P9 and 12). On the circuit boards it's usually just J, and the plug is assumed. The labelling convention isn't solid so it differs from manufacturer to manufacturer, and industry to industry. The manual says to disconnect the harness at J1 and measure across the red and violet wires. I was telling you to unplug J1 and measure across the wires, which is a bit contradictory. I should have been more careful to say measure the wires on the plug you removed from J1. Sorry for the rabbit trail.

So, that sounds more like it. Your lid switches are working, and the readings you're getting on the red and violet wires should be the same whether the machine is pugged in or not, or turned on or not. (Just a note, it's always best not to plug/unplug from the board with the machine turned on).

On the sides of those socket pins you pulled out of P1 are little wings that hold the pins in the plug. Make sure the free end is lifted out and the wing is straight before you put the pins back in so they latch, or they'll just work out again. They're a bit fragile so be gentle. Also make sure the socket openings aren't spread apart, so there'll be good connection. Once they're back in, give them a little tug to make sure they're secure. Reconnect everything, plug it in and turn it on. 

Now back to U20. If the voltage on pin 10 doesn't change when you open and close the lid, U20 is faulty. 

Jeff

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avatar placemarkReply by
mrwright

I'm going to give this a shot. Can you recommend cutters that will be able to fit between u20 and the board?

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avatar placemarkReply by
medphysteo

Cut the pins at the top. That'll give you something to grab onto to pull them out. Any 4" diagonal electronic side cutters will do.

http://www.newark.com/cutters_electronic (see pictures)

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avatar placemarkReply by
mrwright

I just got my replacement chip in the mail this morning and went right to work removing the existing U20 chip and installing the new one. I plugged in the machine, set it to spin at max rpm and let her rip.

15 seconds into the run, I get the LID error again. I feel like I tried everything at this point. 

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avatar placemarkReply by
medphysteo

With the machine turned on and the lid closed, do you read 5V at pin 10 of U20?

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avatar placemarkReply by
mrwright

I get a reading of 4.82V at pin 10 of U20. Thats with one probe touching the contact labeled "GND" and the other probe touching pin 10.

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avatar placemarkReply by
medphysteo

Near the middle of the circuit board on the near edge is a divot that makes room for a post in the cover. To the left are four resistors, R70-73. Between the divot and resistors a little further in you'll see three circuit pads with holes  labelled VCC, GND, and Phase. What voltage do you read between VCC and GND?

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avatar placemarkReply by
mrwright

5 Volt DC between VCC and GND.

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