[R-390] Orange Drop Capacitors

[b_hagen at sbcglobal.net]

Almost off topic but since we are talking about why here's a possible
reason. I am in the process of repairing a 36 year old color TV with a
vertical sweep problem. Well I did do this for a few years back - like 35
years ago but today I don't have a way of running the set with the chassis
on the bench so I decided to do the "shot gun" approach. An approach
reserved for GE B&W portables in times past, but I digress. So I replaced
the 8 or 9 orange drops. It did not fix the problem, by the way. Since then
all the caps have been checked on my Simpson 383A and all check like new,
fresh stock. That's why orange drops IMHO.

Bruce


Bruce Hagen
b_hagen at sbcglobal.net 
-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Flowertime01 at wmconnect.com
Sent: Thursday, January 18, 2007 2:37 PM
To: r-390 at mailman.qth.net
Subject: Re: [R-390] Orange Drop Capacitors

WB5KXO,

The Collins engineers were limited by two things...cost and available
technology at the time.  There were no doubt better caps available than was
used in the R-390A...all one has to do is look back to the R-390/URR to see
that, but cost was the culprit.  Cecil Acuff, Very true. Collins was limited
to parts already qualified as military acceptable. Getting another part into
the support system cost money.

Most of the caps I am aware of that are being replaced in the "A" are paper
caps and the orange drops are very well suited to the job and should out
last the original paper caps by a factor of at least 2. 

Consider that the factor was at least 30 years. 

 No question other caps available today will also do the job. 
I've seen anything from yellow poly caps to German made film caps.  All will
work.  I guess if you wanted to you could change them all with ceramic disks
as is done in the SP-600 series.  I think the orange drops have better
characteristics for coupling and use in audio stages than the ceramics which
are well suited for bypass work.  In summary the orange drop is just hard to
beat for all around general use....and by all means stay away from anything
NOS in paper capacitors.

Cecil Acuff K5DL

-----------------
Good stuff from Cecil.

The orange drops are just considered quality parts. You expect every one to
work as rated and last.

There are much smaller parts than the orange drops. I used some other small
brand in my IF deck. I have so much more space in the deck than before. and
more than if I had used the orange drops.

Most times the orange drops are rated 600 volts. And 300 volt or even 250
volt caps will do fine. The lower voltage is smaller parts size. The higher
voltage is less likely to fail ever under use at the R390 voltages.

Collins was not trying to use bad stuff. You can only buy what is in stock
at the hardware store. Collins could only use what had a stock number and
was a part that could get issued. 

Every part that was not a stock item cost money to get into the logistics
supply chain. After the front panel, wire harness, filters, RF transformers,
how many other new parts do you want to introduce at the cost if there is
something in stock already that will work?

Roger. AI4NI
 

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