Re: Control board U4 8v regulator issue>Solved problem

Posted by WE0H on
URL: http://elecraft.85.s1.nabble.com/Control-board-U4-8v-regulator-issue-tp2420836p2421005.html

I replaced the regulator and now have 8.30v output from U4. The original
regulator only put out 7.61v. Thankfully I had a used regulator on a
parts board from a security system!!! hi hi...

Mike


Mike-WE0H wrote:

> Has anyone else had a 8v regulator (U4) on their control board show a
> lower voltage than it should? Mine shows 7.61v with the board in the
> radio or on the bench with a 14v supply connected to the input of that
> regulator. All components and soldering look correct. The 5v regulator
> is at 5.00v. All functions in the test procedure work as they should
> except the AGC voltage couldn't be set to 3.80v because of the 8v buss
> being at 7.61v, the AGC voltage changed as it should but was lower than
> the 3.80v suggested for setting R1 to.
>
> Nothing runs hot or smells hot. What do you guys think? Bad regulator or???
>
> Many thanks,
> Mike
> WE0H

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