Your "fix" for the too large C67 is likely OK. I have not yet
encountered that situation.
However, I offer a caution about the flux 'wash' you mentioned. I trust
you do not mean to flood the board with flux remover I have attempted
repairs on too many radios that have been "flux washed" improperly
In some cases, flux residue has been washed under the connectors and ICs
and the only fix is to remove the components and further clean both the
component and the board. It makes one great mess and can result in a
malfunctioning radio. Even after such repairs, I 'cross my fingers' and
hope the fault conditions do not reappear.
For what it is worth, HP does flux cleaning of production boards, but I
understand from reliable sources that those boards that end up at rework
stations are *not* to be cleaned of flux. There must be a good reason
for that procedural directive.
Solder flux is non-conductive - as long as no effort has been made to
clean the flux.
The combination of flux and flux cleaners can leave conductive paths
that will react later to moisture in the air and cause malfunctions.
If you *must* clean flux, do it in small areas at a time using the
cleaner (denatured alcohol works) applied with a cotton swab (Q-tip) and
cleaned up with a paper towel piece immediately - repeat until all the
flux is gone. Do not "wash" or "flood" the board or disaster may occur.
If you switch from solder with a Highly Reactive flux (Kester 44 for
example) to a solder with a Mildly Reactive flux, no cleaning is
nesessary (there is very little flux residue). Kester 285 is one
example and the Kester 'No Clean' is even better. Save the Kester 44
for work on antennas and old components which have substantial oxidation
on the leads.
73,
Don W3FPR
On 3/21/2013 9:15 PM, Phil Barnes-Roberts WA6DZS wrote:
Just finishing up a build for Tony, KE6JZF of a K1/KFL1-4/KAT1/KNB1
(#3195), and have found that the 2.2uF-50V electrolytic cap C67 (where
25V is called out in the Parts List) may be a bit too tall.
It doesn't seem to bother at C31, C54, or C10 on the NB board (all
50V). When it came time to bolt the NB to the RF board, C67 was in the
way. After trying to gently re-wet the leads and lean it over U2, I
wound up wrapping a little wire around the (too-short) leads and
mounting it on its side under the board (which seems to fit OK.)
Anybody seen a better fix for this physical interference fit? Final
flux wash is the next step, unless I hear better news.
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