Clamp on Ammeter Broken

Discussion in 'General Electronics Chat' started by bjdobs, Mar 3, 2009.

  1. bjdobs

    Thread Starter New Member

    Mar 3, 2009
    Purchased a Clamp on Ammeter online Cross Border over a year ago and its no longer working ... the circuit appears to use 2 * (TI) 27L2C (Texas Instrument insignia 27L2C 6BM) opamp IC's (4 opamps) which are linked to 2 * 4 pin devices that are taped to opposite ends of the clamps (',)... the only markings on these devices appears to be Z 4 ... not sure if these are Hall Effect devices and or some form of current sensor (there is no physical connection to the clamps/iron cores) ... without further description would anyone be able to help me determine what these devices are and possibly how to test them?

    The actual issue is the meter in A~ mode is contantly reading 600 mA regardless of the current being tested (using a 100W lamp which should read just shy of 1 A ) ... there are 4 pots in around the Clamp opamps that affect this measurement ... I was able to zero out the reading by adjusting them slowly but the meter still doesn't read any current. So I suspect one or both of the devices in the clamp may not be working.

    I recall hall effect devices were prone to mechanical shock and wonder if this was possibly bounced around once to many times.