InspectorGaget
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- Jun 11, 2012
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I ordered from Digi-Key Part number 153-1026-ND Mfg part no. LED4-16264 (Backlight for transfl glass ILED)
Note: this is tall enough but you will loose illumination of the scan/man on the left and the HZ on the right. Not a problem as this is information is redundant(if you can not tell by the other indications that the scanner is in scan or manual quit reading this now). This green led back light assembly makes the scanner display bright and sharp. Readable in any lighting. It runs on DC(marked + and -) 4 volts 70 ma max. I run my scanner on an external 13.6v regulated supply so the + voltage at the brown wire of the volume control on-off switch is 13volts. With this I used 100ohm/1w and 58ohm/1/2w resistors in series. to drop the voltage and get 60ma of display current(if you have a different supply voltage or want to use one resistor do the math for the resistance and power dissipation allow double power dissipation safety factor on the resistors so they don't get to hot). The circuit is ground through the display, then the resistors, then to the display on-off switch contacts, then to the brown wire on the volume control on-off switch. Ok. Disassemble the display front panel from the scanner. desolder and remove the large metal shield cover from over the front of the circuit board. Remove T501. Cut the circuit path on the supply side of C504. you can now use the feed eyelet to the right to attach one end of the resistors in series(this is the center pole of the display switch). the other end of the resistors goes to the output pads of the old T501 transformer(removed) that feed the display illumination(we use the same illumination power points. now on the circuit board find r504/r505(mine only had one) remove so both are gone. attach a feed wire to one r504/r505 pads that feed the display switch so you get contact closure when the button is IN. run this to the brown wire on the volume control on/off switch. You now have disabled all the old feed and have the 4volts/60ma available to run the new back light. On to replacing it. Desolder the old display illumination backlight wires from the circuit board. cut the glue blob(underside) and slip out the old strip(I used a single edge razor blade). Pry up on the plastic end display support where it attaches to the ckt board. cut any glue or index bumps on it and slip it out. solder 2 solid wires(about 22 ga) to the new display illumination board similarly to the old one. - goes to common board ground. Slip the new display illumination board(remove protective cover strip first) so the light side faces the the front of the unit. Slip it in place in the center left/right. the plastic sponge will keep it pushed against the liquid crystal display. the display wires will keep it in place up and down and the stiff feed wires you attach to the display driver board(where the old one was soldered) will keep it in place left/right. reassemble you are done. My total cost under 11 bucks(I had the resistors)
Note: this is tall enough but you will loose illumination of the scan/man on the left and the HZ on the right. Not a problem as this is information is redundant(if you can not tell by the other indications that the scanner is in scan or manual quit reading this now). This green led back light assembly makes the scanner display bright and sharp. Readable in any lighting. It runs on DC(marked + and -) 4 volts 70 ma max. I run my scanner on an external 13.6v regulated supply so the + voltage at the brown wire of the volume control on-off switch is 13volts. With this I used 100ohm/1w and 58ohm/1/2w resistors in series. to drop the voltage and get 60ma of display current(if you have a different supply voltage or want to use one resistor do the math for the resistance and power dissipation allow double power dissipation safety factor on the resistors so they don't get to hot). The circuit is ground through the display, then the resistors, then to the display on-off switch contacts, then to the brown wire on the volume control on-off switch. Ok. Disassemble the display front panel from the scanner. desolder and remove the large metal shield cover from over the front of the circuit board. Remove T501. Cut the circuit path on the supply side of C504. you can now use the feed eyelet to the right to attach one end of the resistors in series(this is the center pole of the display switch). the other end of the resistors goes to the output pads of the old T501 transformer(removed) that feed the display illumination(we use the same illumination power points. now on the circuit board find r504/r505(mine only had one) remove so both are gone. attach a feed wire to one r504/r505 pads that feed the display switch so you get contact closure when the button is IN. run this to the brown wire on the volume control on/off switch. You now have disabled all the old feed and have the 4volts/60ma available to run the new back light. On to replacing it. Desolder the old display illumination backlight wires from the circuit board. cut the glue blob(underside) and slip out the old strip(I used a single edge razor blade). Pry up on the plastic end display support where it attaches to the ckt board. cut any glue or index bumps on it and slip it out. solder 2 solid wires(about 22 ga) to the new display illumination board similarly to the old one. - goes to common board ground. Slip the new display illumination board(remove protective cover strip first) so the light side faces the the front of the unit. Slip it in place in the center left/right. the plastic sponge will keep it pushed against the liquid crystal display. the display wires will keep it in place up and down and the stiff feed wires you attach to the display driver board(where the old one was soldered) will keep it in place left/right. reassemble you are done. My total cost under 11 bucks(I had the resistors)
