Re: Two QCX kits (80m and 40) - both with shorts on Si5351A - fixed

Arv Evans


Unfortunately it is impossible to perform quality control on assembled kits at the purchaser's location.  Also probably impossible to perform knowledge tests on those assembling the kits.  Even Heathkit never found a solution to assembler introduced problems.  

With over 8000 workinking kits out there it would seem that the design is solid.  Quality of shipped kits must be relatively good or the units would not be this popular.


On Wed, Dec 11, 2019, 2:11 PM Hans Summers <hans.summers@...> wrote:
Hi Geoff , Nick

Hans has mentioned in the past that the number of QCX's sold is around 4000 but given the number of builders who have purchased several units, the true number of purchasers must be only a few hundred!

You are far far out of date OM... current quantity is 8,885... 
Conclusion - don’t let it put you off - just check the legs of the Si5351A on the bare board before you start - it may save you some disappointment:

Still highly recommend - the best kit I have seen.
Thanks Nick... You should play the lottery OM. But avoid thunderstorms, they say lightening doesn't strike twice but... hi hi. 

Here we have assembled a large number of QCX kits for the shop at a rate of 3-4 per week over the last 18 months or more... and I do not recall having seen a short on Si5351A pins once in all that time. I know it does happen occasionally, but I think it is pretty rare. Anyway I am glad you solved it and still enjoy the kits!

This does illustrate a problem with kits... it isn't easy to do a full Quality Control check before you ship it out. It isn't practical to examine the whole thing for every type of failure under a microscope, and count every resistor and capacitor, etc., for every kit shipped. When you have a completely manufactured product (not a kit), it is possible to power it up and do a Quality Control check which it either passes or it doesn't. Producing kits is a very tough business :-)

73 Hans G0UPL

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