[W126 Coupe] clock problem

Fri Aug 18 07:58:59 EDT 2006

Yes, Markus, as is the case with most automotive gear, there is only one cable powering the gadgets and it is + 12V. Negative is feeded via the metal body of the gadget itself which is mostly attached to a metal part of the car.

As for your case, since the instrument cluster is mostly non-metallic, there is a printed circuit on a sheet of plastic which is attached to the back of the instrument cluster and the negative contact is supplied by special parts of this circuit which comes into contact with the body of the concerned gadget.

Therefore, you still can continue to be lazy. All you need to do is connect a ground to the metal case of the clock. If the case is non-metallic, then there is a screw hole for sure where it gets the ground contact you can use.

Unfortunately my car has the so-called computer and thus a digital clock. Otherwise I could have inspected mine and tell you the exact point.

Good luck,

Vedat Iplikci
1987 560 SEC Euro
  ----- Original Message ----- 
  From: Markus Meyer 
  To: saveks at superonline.com ; mbcoupes at mbcoupes.com 
  Sent: Friday, August 18, 2006 2:15 PM
  Subject: Re: [W126 Coupe] clock problem

        Vedat,

        I do have a voltmeter so I'll check that out as you describe. >From what I see on the back of our clusters, the tach/clock "piece" screws into the cluster housing itself. Then there are only two wires plugging into it - one for the tach, the other for the clock. I don't see any other wires that would be a ground, so maybe there is a common ground to the entire cluster which works when all pieces are screwed together and attached, and the new clock isn't working by just plugging the power wire in without being attached to the rest of the cluster? I was trying to avoid removing the entire cluster, taking it apart to replace the tach/clock and put it all back together to find out it doesn't work and I have another problem. But I guess I don't have much of a choice now and need to stop being lazy!

        Thanks,
        Markus

        Markus Meyer
        484-919-9762 (cell)
        http://www.meyerprobateproperties.com/

        --- On Fri 08/18, Vedat Iplikci < saveks at superonline.com > wrote:

          From: Vedat Iplikci [mailto: saveks at superonline.com]
          To: mfmeyer at iwon.com, mbcoupes at mbcoupes.com
          Date: Fri, 18 Aug 2006 11:27:20 +0300
          Subject: Re: [W126 Coupe] clock problem

          Hi Markus,

          To check if the power cable is live, you need a voltmeter and test for 12V. The red (live) probe to the clock cable and the black (neutral) probe to any good metal point on the chassis. If you don't have a meter around, you can easily test it with a known to be working 12V bulb also.

          To check the clock itself, connect the red cable from the battery to the connector where the original power cable is connected on the clock. For the black, you should inspect the clock to find a negative connector. If there isn't any, then the body of the clock is the correct point for the black cable. You can verify this by inspecting the clock's original position in the intrument cluster. It must have some point where the negative connection from the cluster contacts the clock body.

          If the clock doesn't work, then your last resort would be a capacitor change.

          Hope this helps,

          Vedat Iplikci
          1987 560 SEC Euro

            ----- Original Message ----- 

            From: Markus Meyer 

            To: mbcoupes at mbcoupes.com 

            Sent: Friday, August 18, 2006 3:54 AM

            Subject: [W126 Coupe] clock problem

                  Hi gang,

                  I'm hoping someone can give some suggestions on what to do with a clock problem I'm having. Last year it was acting up, so on Dick's suggestion, I sent it to the Benz store in Georgia (after unsuccessfully trying to put in new capacitors myself) and got a rebuilt one. Worked fine until last month when it suddenly just stopped working. Fuse #2 which says clock also works other items that are working, so I'm assuming its not as simple as that. Right now, I have the cluster pulled out enough so that I could take the power wire off the old clock and attached just that to the new clock, and its not moving. So, I'm assuming that power wire is bad? 

                  1) How can I check if the wire is "live" or has power?
                  2) How can I check the clock by itself. I know hook it up to a 12V battery, but how - where do the red and black wires go to from the battery to the clock?

                  Other ideas on what to check for? Anything obvious I'm just missing? Everything else in the cluster, including the tach, work just fine.

                  Thanks,
                  Markus

                  Markus Meyer
                  484-919-9762 (cell)
                  http://www.meyerprobateproperties.com/

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