George,
No immediate positive answers, but that sounds suspiciously like a bad
solder connection or an unsoldered connection somewhere.
The blank display would be associated with the Front Panel board and the
surrounding components (refer to the schematic to identify those
components) and reflow those first.
Ask him to reflow the soldering with an iron temperature of 750 degF or
a bit more. Add a bit of additional solder (actually the additional
flux is what is required). Observe the solder as the connection is
heated, it must flow out onto the component lead and the solder pad
fully before removing heat. There should be a small visible fillet of
solder around the component lead. A solder "ball" can mask a bad
connection, and if there is a ring around the component lead, that is
also a problem. As one builder stated - the solder connection should
look like a mountain, but not a volcano - I forget the source of that
original comment, but it is a good description of a good/bad solder
connection.
Note also that the front panel switch leads do not project very far on
the solder side, and it is possible to have soldering over the solder
pad that does actually contact the switch lead. Re-flow the soldering
with a tip width that allows the switch lead to be heated. Na
alternative is to solder the switch leads from the component side of the
board. Be careful not to let the soldering iron to contact and melt the
switch body if you take that alternative.
If he is using lead-free solder, bump the soldering temperature up to
800 degF. Note that lead free solder does not flow well. The use of
lead-bearing solders is my recommendation (although Elecraft cannot
officially acknowledge that fact due to RoHS compliance restrictions).
The RoHS restrictions do not apply to ham built kits, but do apply to
factory built assemblies. Since the K1, K2, KX1 and XV series
transverters are kit built, the use of lead-free solder is not
required. Since a K1 is not likely to be destined to the landfill,
using leaded solder is not an impact to the environment - consumer
"throw-away" devices are the major contributor to landfill lead, and
properly should be RoHS compiant IMHO.
If the soldering turns out not to be the problem, I would suggest that
the next step is to refer to the DC Voltage chart in the last few pages
of the manual.
73,
Don W3FPR
On 2/22/2016 5:34 PM, George Davis wrote:
A fellow club member is building K1 and has reached the Rx alignment stage.
However he has an intermittent fault which gives a blank display and an audio
tone in the phones.
Any ideas where to start looking.
George. G3ICO
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