[Elecraft] No Backlight K2

[Don Wilhelm]

Oscar,

If you want to troubleshoot it, look at the schematic and follow the path
for the voltages applied to D2 and D3 with your DMM, you can approximate 1.5
to 2 volts drop through each LED if it is conducting.

The most likely thing is that you have failed to solder a connection, check
R9, R10, R11, Q1 and Q2.  Be certain Q1 and Q2 are oriented properly, and be
certain U3 pin 17 has been soldered.

73,
Don W3FPR


> -----Original Message-----
>
> Well, thanks to great forbearance on my wife's part over this little
> holiday vacation, K2 #5630 is coming right along. I finished up Part
> 1, and all the tests are just fine _except_ that I have no backlight.
> The LCD reads fine, but there's no change in it or in the LED
> brightness when I switch between night and day. I haven't tied it in
> a darkened room, but I am assuming I should be able to tell whether
> the backlight is on even in normal room light.
>
> At first I had the terrible fear that I should have taken the white
> film off the diffuser, but an archive search told me I was right to
> leave it there. But now I don't know why I don't have the back light.
>
> Any advice on the most efficient way to troubleshoot this?
>
> Thanks!
>
> Oscar WV1C
>