[Elecraft] KPA initial voltage checks

[Don Wilhelm]

Don,

Is U1 installed the 'right way around'?  The voltages you measured with U1
removed seem to be correct for that condition.
You may have a faulty U1 on your hands.

73,
Don W3FPR


> -----Original Message-----

> Hi Guys,
>
> I seem to have K2 #5885 perking along quite well. I also installed
> the NB, DSP, SSB board and 160 board. With those behind me, I'm on to
> the KPA 100.
>
> On my initial voltage checks, page 25 of the manual, I'm getting some
> bad readings.
>
> Test Point                Reading                 Should be
> U1 pin 1                     7.0                        5.0
> U1 pin 7                     8.0                      0 - 0.1
> U1 pin 13                   7.0                      0 - 0.1
> U1 pin 20                   7.0                         5.0
> U1 pin 27                    7.6                        5.8
>
> U4 pin 11                    5.8                        5.0
>
> I pulled U1, and all readings were within spec except for
>
> U1 pin 7                      13.1                     0 - 0.1
> U1 pin 27                     8.0                        5.8
>
> So, it seems that voltage regulator U3 is OK, as it reads 5.0 with U1
> out of the picture.
>
> Could I have a bad Q12?, or is it possible U1 is the culprit, or ????
>
> Thanks
>
> Don
> W0DJC
>
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