[Hallicrafters] R45/ARR-7 Receiver by Hallicrafters

[bonddaleena at aol.com]

Hi to all.
I've made a 'sub' hobby of replacing old, paper caps in all my vintage equipment. All the paper caps in my SX-101A were leaky, when tested at the rated voltage (although they will always check OK with a 9 VDC cap meter). On my Collins 75A-4, all the BBOD were very leaky, as expected, but also one of the mica caps.
In the thousands of caps I've tested, I have only found ONE (shorted) disc cap.

My only regret, is throwing out several buckets of BBOD/Bumblebee caps. I could have made major $ on eBay. (re: "tone caps") 

YMMV

ron
N4UE



-----Original Message-----
From: w5jo <w5jo at brightok.net>
To: hallicrafters <hallicrafters at mailman.qth.net>
Sent: Mon, Mar 5, 2018 5:19 pm
Subject: Re: [Hallicrafters] R45/ARR-7 Receiver by Hallicrafters

I was given an SX 42 some time back that was cosmetically pretty good and my 
resistance measurements looked good so I decided to do the necessary work to 
get it going.

It played nicely for a while then suddenly went deaf.  It took some time but 
I finally found one of those "postage stamp" micas in an IF can that had 
developed a low resistance short to ground which took the AGC line down.  so 
those mica caps can cause trouble if the seal around where the wire enters 
the case becomes compromised and allows moisture to enter.   This is not the 
first receiver where that problem came up, I have seen it in IF cans in 
several National NC-183D receivers among others.

So don't assume one way or the other but be aware the type of material, 
paper or mica, may not matter and if I am working on an area with those 
things, I go ahead and replace them  so I don't have to get into tight spots 
a second time.

Jim
W5JO


-----Original Message----- 


    Dot I mean is the upper left corner of six dot coding of the
sort found on postage stamp mica caps. Silver or white for paper,
black for mica.

On 3/5/2018 11:54 AM, Alf Fisher wrote:
> Hi Richard,
> Thanks for the info.
> I will have to have a better closer look at the caps to see who made them.
> Alf



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