How to determine the authenticity of the ROMH diode

发表于2020-08-07

  1. How to determine the ROMH diode true or false? ROMH's diodes have become a household name in the electronics industry. It is inevitable that there will be fake and inferior products. There are many knock-offs of low-end brands, all of which are printed directly with the ROMH logo. Today, the ROMH Agent teaches you how to determine the authenticity of ROHM diodes.


    1. The pin

    All tin-plated pins that are as shiny as new are refurbished. The pin of the genuine ROMH diode should be a so-called silver pink pin, dark in color but uniform in color, with no trace of oxidation on the surface. In addition, there should be no scratches on the pins of DIP and other plug-ins. Even if there is one (only after repackaging), it should be neat and in the same direction. The exposed metal should be smooth and free from oxidation.


    2. Measure the thickness of the device and the edge of the device

    Many original laser printing of polished renovation (usually power device) to remove the original logo, it is necessary to grind the darker, such devices overall thickness is significantly smaller than normal, but if you don't compare or measured with a caliper, usually lack of experience or it is difficult to distinguish, but there is a flexible way, is to see the edge device. The edge of the device is rounded (R Angle), but the size is not large, because the plastic seal device must be "moulded" after injection molding. In the polishing process, the rounded corners are easily ground to right angles, so the positive edge of the device is at right angles, which can be judged as refurbished goods.

    In addition, the use of laser marking machines to modify chip marking has been increasing recently, especially in memory and Murata. Once the position of the laser print is found to have a single letter and a pen of uneven thickness, it can be regarded as a refurbishment.


    3. Check the surface of ROMH diode for marks of polishing

    The surface of the polished ROMH diode will show fine lines and even traces of previous printing. Some of them are coated with a thin layer of paint on the surface of the ROMH diode, which looks lit and has no plastic texture, to hide the polish marks.



    4. Look at the production date of the device and the label of the packaging plant

    The authentic ROMH diode label, including the diode underside label, shall be consistent and the production time shall be consistent with the device product, the refurbished label shall be confused and the production time shall be inconsistent. And even though the front label of the chip is the same, sometimes the values are unreasonable (such as "Geely number") or the production date does not match the component. If the label on the bottom of the device is messy, it means the device is refurbished.



    Look at the print

    At present, most ROMH diodes are marked with lasers or printed with a dedicated chip printer. The handwriting is clear, unobtrusive and not blurred, and cannot be easily erased. The refurbished ROMH diode, on the other hand, had either a "sawtooth feel" at the edge of the writing, corroded by the cleaning agent, or the print was blurred, varied in depth, out of place, easy to erase or too conspicuous. In addition, the screen printing process has long been phased out in IC major factories, and some manufacturers are still using the screen printing process for cost reasons when refurbishing, which is also one of the judgment basis, the screen printing word will be a little higher than the ROMH diode surface, you can feel the slight uneven hand touch.