06-20-2015, 06:53 PM
Hi Dan, how's the blower coming along?
In the first photo, it looks like a corroded solder joint on the +5volts powering the infra-red LEDs - between the two Phirrips screw heads are two solder pads, one on the left is probably the 0 volts, one on the right the 5-volt - if you trace the track from that solder pad it goes to the three black-with-stripe diodes and through the to the LEDs - if that joint's bad, the LEDs won't light (invisibly!) to illuminate the photo-diodes or photo-transistors that switch the outputs on and off. With the reader powered you should see 5v across those pads, and from the 0v to the common ends of the diodes, slightly lower voltage at the far (stripy) end of the diodes.
Try wiggling the wire coming in on the other side of the board while looking at those solder pads through a magnifier (or better a loupe eyeglass) to see whether the joint's still intact, if not first step would be to clean (isopropyl alcohol and a gentle scrape) the pads and wire ends, dab on some flux (Maplin do a "flux pen", a felt-tip with soldering flux in it) and attempt to resolder the wire to the pad.
USE PROPER LEADED SOLDER and a hot iron to minimise the time it takes, or you could cook something, leaded solder's still available for repair work (and military, aviation and medical electronics plus "safety critical" applications, as lead-free isn't as reliable...) although you may not be able to find it in Maplin etc - try EvilBay?
Hope that helps
In the first photo, it looks like a corroded solder joint on the +5volts powering the infra-red LEDs - between the two Phirrips screw heads are two solder pads, one on the left is probably the 0 volts, one on the right the 5-volt - if you trace the track from that solder pad it goes to the three black-with-stripe diodes and through the to the LEDs - if that joint's bad, the LEDs won't light (invisibly!) to illuminate the photo-diodes or photo-transistors that switch the outputs on and off. With the reader powered you should see 5v across those pads, and from the 0v to the common ends of the diodes, slightly lower voltage at the far (stripy) end of the diodes.
Try wiggling the wire coming in on the other side of the board while looking at those solder pads through a magnifier (or better a loupe eyeglass) to see whether the joint's still intact, if not first step would be to clean (isopropyl alcohol and a gentle scrape) the pads and wire ends, dab on some flux (Maplin do a "flux pen", a felt-tip with soldering flux in it) and attempt to resolder the wire to the pad.
USE PROPER LEADED SOLDER and a hot iron to minimise the time it takes, or you could cook something, leaded solder's still available for repair work (and military, aviation and medical electronics plus "safety critical" applications, as lead-free isn't as reliable...) although you may not be able to find it in Maplin etc - try EvilBay?
Hope that helps
Rules are for the obedience of fools, and the guidance of wise men...
(Douglas Bader)
(Douglas Bader)