Question for Dallas Smith: I want to replace neons with LEDs in my Fluke 845AB.
Following your instructions below, did you mount the LEDs where the neons were on the PCB and use the plastic light tubes or did you mount the LEDs hard up against the LDRs in the yellow foam block? Thanks, Lou Quote Dallas Smith, 2 years ago Permalink <http://narkive.com/bdOZWNXt.1> Raw Message Report “Finally got around to modify my Fluke 845ab with LED 's for the chopper circuit. Used the 17 volt windings for LED's (Mouser 941-C513AMSNCW0Y0511 Warm White Round LED) instead of the 130 volt, move red wire on transformer pin 9 to pin 7.This winding is 180 degrees out of phase, so I reversed the steering diodes (CR106 & CR107) I left in to help make sure the phase was correct for the LED's when connecting. Change R154 to 6K to set the brightness, selected for good operation of the zero control. Then install jumper to replace C119. Also changed the filter integration response caps C111 to .022uF and C116 to 47uF, this stabilized the jitter to a manageable mode of operation. Meter now works as well or better when the original neon's worked.” Lamp Blocks _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
