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Automated Fixtures Clay Paky Alpha Spot gobo wheel issues

Discussion in 'Lighting and Electrics' started by scobrakid, Jun 3, 2009.

  1. scobrakid

    scobrakid Member

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    Hey all! If anyone is familiar with Clay Paky Alpha Spot HPE 575 repair, or any other related gobo wheel issues I'd sure love the input, because I am stuck at the moment.

    The first signs of malfunction I noticed was a gobo wheel consistently rehoming whenever its DMX value returned to 0 (from any value up to 255). This occurred while console-controlled and independent as well, so I could rule out console error. I spoke to a distributor representative who knows a lot about the Paky brand and he advised replacing the magnet that the gobo sensor uses to detect the wheel, since those have been known to deteriorate. I inserted the new magnet in the replacement position and tested the fixture. The gobo wheel homed to the new magnet. Success... I thought. The same problem occurred with the new magnet when DMX value returned to 0, the wheel rehomes and does not respond to signal during that time.

    This dilemma is particularly frustrating because we spent 40 dollars on a magnet smaller than a #2 pencil eraser and heat-resistant tape. I would really like to identify the actual problem this time to avoid unnecessary expenses.

    If anyone is familiar with this problem on Clay Paky's or even other fixture types, please respond. I definitely appreciate it.
  2. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    Phoenix, Az
    Is it just a magnet that is the sensor or is there an optic sensor in there aswell because recently our Coemars needed some TLC in the optic sensors (alcohol swabs should do the trick to clean em)
  3. JD

    JD Well-Known Member

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    North Wales PA
    "Hall Effect" transistor is used to sense the magnet. They go noisy.
  4. PRGDistributionTechServ

    PRGDistributionTechServ Member

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    Hi scobrakid

    It sounds like you have "the infamous black ring" on the back of the Gobo Wheel. The early generation Alpha series suffered from 3 issues which all caused the same problem. The machine is homing the Gobo wheel when you pull down the channel to zero because it is not seeing the magnet. It is either not correctly positioned "plunger or black ring" or the sensor/magnet is bad. Check the sensor using sensor test in the test menu. Operators manual is down loadable at Clay Paky - Professional Show Lighting select English then user support followed by moving body luminaries and then Alpha Spot HPE 575 for instructions. Listed below are the 3 main causes which have been corrected in newer units. Clay Paky was also very generous and proactive about warranty repairs on the early units.

    1) Magnet failure. Clay Paky corrected this by offering a new magnet and some aluminum tape that was much better suited for the job. Replacing the magnet and not correctly installing the new one will not correct the problem. The sensor responds better to one side of the magnet. Place the new magnet on the back of the magnet on a known good machine and mark a side for reference. I say a known good one because that may actually be the problem with the unit you are trying to correct.

    2) In some units the small plunger used to break the gobo wheel needed to be adjusted. The best spec for this is the white tip should be depressed half way. We found that loosening the 8mm nut on the back and turning the plunger a half turn counter clockwise to be very successful.

    3) Black Ring. The grease on the back of the Gobo wheel where the plunger contacts needs to be replaced. It should be white. This was very common when the fixtures were used in shows with a lot of fast gobo changes for long periods of time, but is easily resolved with regular maintenance. Use a foam Q-tip to remove the old grease and re-apply new. We would use a hobby knife to life the plunger a bit to allow the new grease to get under the tip if it was really bad. If it was really bad it required the wheel to be removed and the plunger replaced. Especially if Pyro was extensively used around the units for long periods with no maintenance. Use the Clay Paky "Million Dollar Grease". 030649/001
    scobrakid and (deleted member) like this.

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