[Collins] Paper or plastic Thanks! and now alignment
Paul
[email protected]
Tue, 25 Feb 2003 08:37:45 -0800
Hi Fellows,
I would like to thank everyone who answered my post on the best caps to
replace the old paper and oil filled caps in my 388 and 51J4. Excellent
suggestions were made and saved me from making some serious errors, plus
saved me a lot of work.
I am ordering Orange Drops to replace any leaky caps I find.
Thanks again group!
Now I need to do an alignment. Are there any tricks to do this that may be
different from the technical manual, in light of the fact that there is now
readily available decent test gear, that wasn't back when these were new?
i.e. If one has an IFR1500, an 8640B and a 475A scope, would the procedure
be any different? I started last night by trying to get the XSTAL osc tuned
for all bands, the one that's supposed to have 32pF across the xstals. Well,
it took an hour just to set that! My cap meter didn't like the fact that
there is a 100K R across the cap. I didn't want to clip out the R and didn't
have a bridge to do the measurement so I just powered the radio and measured
the xstal output with a loop going into the service monitor and tweaked C167
until I averaged the center freq of each xstal. Some were a little high,
some low, but no more than 1KHz. Actually, I guess that's not that good,
considering some of them get multiplied 3 times! Arg. An alignment should be
pretty straight forward but at 11:30pm even the simplest task can become a
major project.
You're thoughts, tips and suggestions are welcome.
Thanks and best regards,
Paul
VE7KHz