[ARC5] RAK-7 caps - newest radio adventure

[Glen Zook via ARC5]

It has been my experience that the "bathtub" capacitors are starting to go bad on a regular basis.  In years past, such have, generally, not been a problem.  As such, I now routinely replace those capacitors wherever they are found.  Yes, a number of them are still good.  But, new capacitors are inexpensive and installing them will definitely prevent damage caused when the bathtub capacitors fail.
A lot of the "mica" capacitors are actually "Micamold" capacitors which are definitely "paper" types.  Those are almost certainly leaky and need to be replaced.  True mica capacitors are now going bad, on a regular basis, and need to be replaced.
As for resistors:  Those are a crap shoot!  I find many resistors that have held their value, within tolerance, very well over the decades.  But, there are also those resistors that have changed value and are "way out" of tolerance and definitely need to be replaced. Glen, K9STH 
 Website: http://k9sth.net
      From: Kenneth G. Gordon <kgordon2006 at frontier.com>
 To: Bill Cromwell <wrcromwell at gmail.com> 
Cc: Arc5 at mailman.qth.net 
 Sent: Monday, August 24, 2015 10:47 AM
 Subject: Re: [ARC5] RAK-7 caps - newest radio adventure
   


Well, I didn't say THAT, exactly: what I said was that all of the caps, except 
those between stages, are oil-filled and very seldom give trouble.

Well, I have never had one of those oil-filled jobs short out, or even go 
leaky...yet.

I strongly suggest you test the oil-filled caps before "shot-gun" replacing 
them. I think you will find that most, or even all, are just fine.

The mica caps (if they really ARE micas) are, routinely, leaky. As I said, you 
can tell this by listening to the receiver without an antenna connected. If you 
hear "static" one or all of those are bad. I have found so many of those bad 
over the years that I routinely replace them now.

THOSE are far more likely to be out of spec than the oil-filled caps, Bill. FAR 
MORE likely.

Good luck.

Oh: BTW, the only real differences between the RAK-5 and the later models 
is the antenna input setup.