Thanks Gernot. The RF board was already assembled when I bought the unit - I didn’t do any soldering.
I’ve spent two days going through the boards with a fine tooth comb (aka strong magnifier) and I can’t find any solder bridges or poorly seated components. I did wake up with an idea in my head at 3am though, so I have another avenue of attack to try this afternoon. Thanks for the suggestions everyone! I’ll post when I’ve tested my idea. 73 -Adrian KJ7SOY > On Feb 16, 2021, at 7:10 AM, [email protected] wrote: > > The resistance checks are meant to measure at U13 after being placed and > soldered. It is not a component check, but it will check if you have done the > placement and soldering of all the connected stuff correctly. IAW, a > different value could mean you did a mistake somewhere else. Visually inspect > the boards, solder joints etc before you pull out the component. In case you > already did it, then just test the 7808 outside of the board. Put 12V to > Pin1, GND to Pin 2 and check if you get 8V at Pin 3. > > Happy building, > Gernot DF5RF > >> Am 14.02.2021 um 22:32 schrieb KJ7SOY: >> Hi everyone! I’m new to the list and to Elecraft radios and HAM in general. >> Thanks for bearing with me while I learn! >> I picked up an unassembled K3 at an auction three weeks ago. It’s been >> sitting in a box with most of the boards sealed in their anti-static bags >> since 2009. I’ve hit a snag and I’m hoping someone here can help. >> I have the rev B RF board and I’m doing the manual’s resistance tests. >> Voltage regulators U12 and U13 are both supposed to test at > 150 ohms. U12 >> passes but U13 tests at 87 ohms. This unit has never been powered up so I >> suspect it has to be a bad regulator. I can solder a board just fine and >> assemble PCB’s but I’m not overly comfortable with hardware debugging. I’ve >> removed the side cover and checked for loose boards, bad connections, etc. >> with no success. Anyone have any ideas how I should proceed? Do I just >> replace the regulator? Do some other debugging? >> Thanks! >> 73 >> -Adrian >> KJ7SOY >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
