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
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