Re: Help with strange audio fault #qcx


Alan de G1FXB
 

Another source for a stiff bristle brush are tooth brushes.
Best ensure the brush is no longer in use to maintain domestic harmony,
else yours may get similarly repurposed elswhere.

To kill any "chinese whispers" check out Hans excellent assembly manuals,
V3 and earlier C21 /C22 were listed as 10uF polarised electrolytics, so polarity conscious, the silk screen was marked accordingly.
With V4, they became 1uF ceramics, and the silk screen suggest the polarity markings have being removed?.

If someone who is building a V4 kit and in doubt, perhaps take a photo of the component silk screen & both sides of an 105 capacitor and post them here?

Alan


On 11/01/2019 18:52, Chris Wood via Groups.Io wrote:
Ted

I had a problem with my 30m QCX which had some similarities to yours.  I think it was a dry joint and I seem to have solved it without knowing exactly what it was, by resoldering everything in sight.  One thing to check is C21 and C22.  They are now '105' in version 4 - mine were buff coloured blobs.  From memory, they were not easy to read but appeared to be polarised - if yours are, you might want to check they are the right way round, if you haven't done so already. 

Good luck

Chris
G4CWS

Join QRPLabs@groups.io to automatically receive all group messages.