Question moved to proper eHam.net category.
My LogiKey K-3 has died. I am stuck.
Does anyone have a K-3 or K-5 that they would like to sell? Any help?
Thanks
Dick, K6KSG
Dick -
WHAT is wrong with your Logi-Key K-3 ?
Schematic is on last page (page 26) of the manual.http://www.idiompress.com/K3_Manual_Tutorial.pdfThere are ONLY 2 integrated circuits in this K-3 keyer.
SIMPLE Design to fix.Freescale 68HC705C8* and 24C16
http://cache.freescale.com/files/microcontrollers/doc/data_sheet/MC68HC705C8A.pdf?pspll=1Transistors: 2N2222A (3), MPSA92
Voltage Regulator, 7805, 1A type device (7805)
This device may have a heat sink, due to current draw and voltage drop.In the newest K-5 (2004 design), they used the surface mount: NJM78L05UA
http://www.mouser.com/ds/2/294/NJM78L00E1-196913.pdf===
A transient on your +12 VDC input can damage the +5 VDC regulator.
I would FIRST check with a DVM that you have +5 VDC after the regulator.