There are EPROM memory chips with a window, these chips can only be erased with ultraviolet light. A beam of ultraviolet light of a certain intensity must be directed into this window, and the information stored in the chip will be erased and the chip can be reprogrammed.
I have an am27c256-155dc chip, which is an EPROM. This chip contains information, which you can see as 1F or 3F. It is not possible to erase this information electrically.
To erase this chip and similar ones, I built a device capable of doing this. This requires a high-voltage voltage converter and an ultraviolet lamp. I took the converter from an old scanner. Today, scanners use LED backlighting, while previously they used fluorescent lamps. My converter is based on two D1616AL transistors, and it's a low-power converter, but it's sufficient for the job.
Instead of a fluorescent lamp, you need to connect an ultraviolet lamp. I have a Philips TUV 4W lamp available.
Connect the two generator wires as shown in the photo. Do not apply high voltage to the bulb contacts, otherwise black spots will appear inside the bulb due to worn filaments. Wrap the bulb in foil and move and reposition the foil on the bulb. Also, do not look into the bulb while it is operating.
Place the lamp directly on the chip and wait for about 30 minutes.
Now for testing. Hooray, the memory chip has been erased and can be re-flashed.
Power consumption from the power supply was 17V x 110mA = 1.87W. The lamp emitted approximately 1.3W.
Comments
Post a Comment