For Dallas Smith Thanks for the info. It is in keeping with the original design. My 845AB 15v supplies are currently down and I suspect the germanium transistors around T202 may be leaky?. Am thinking of replacing them with Si transistors. Your thoughts? Regards, Lou
On Mon, Jun 6, 2016 at 12:35 PM, Dallas Smith <[email protected]> wrote: > Hi Lou, > > Its been awhile since I made this mod, but I had the foresight to save the > project to K04BB's site. > > K04BB /Fluke/Fluke 845A AB < > http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Fluke/Fluke_845A_AB > > > > Still works great, hope you have the same results. > > Dallas > > > > On 6/5/2016 9:51 PM, Lou Amadio wrote: > >> 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. >> >> >> > _______________________________________________ > 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. > _______________________________________________ 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.
