[R-390] Out from the shadows ...

Fri Jul 29 09:33:56 EDT 2005

Well Scott you can believe what you like but the majority of experience has 
been somewhat different and is well documented.  If your statement was aimed 
at the R-390/URR you would be correct....but that's not the case with the 
"A".

To say there are only two or three caps that will ever need replacing is 
completely misleading...especially to a new and inexperienced list member.

While I don't advocate a wholesale replacement of the caps it is likely that 
many of the molded paper caps, be them brown or black, are electrically 
leaky at minimum and possibly split at the seams.  While they won't kill 
things in the role of bypass cap and in most locations as coupling caps the 
few you mention will damage the mechanical filters.  The others will affect 
the overall performance of the radio and place unnecessary load on the power 
supply.  The trick is figuring out which ones are bad and which are not. 
Since it's just as easy to replace them as it is to lift one end and test 
them many choose to just replace them.  Many also may not have the equipment 
to properly check the caps at their rated voltage so again changing them 
gets the job done.

I know I am preaching to the choir here because you have heard all this 
before and I'm not going to change your mind but Mike needs to understand 
the issues and make his own mind up as to the direction he feels comfortable 
with...I have no real issue with either camp....they are your radio's.

Mike the hum from the power supply is probably loose iron in transformer. 
The only fix may be to replace the power supply.  I've read of this 
happening before but have never experienced it.  I do agree with Scott that 
you need to have the filters rebuilt.  You can go with his recommendations 
or if you would like them to look original you can send them to Chuck Rippel 
and he will rebuild the original cans.  www.r390a.com

Or if you feel up to it you can rebuild them yourself.  There is info on 
Chucks page and in the archives on how to do the work yourself.  I am about 
half way through documenting that process myself and had to put it on the 
back burner to restore an R-390/URR.  I hope to get back to that radio in 
the next few weeks.
It's not really that hard...a little messy though!

Welcome to the group and have fun.....

Cecil Acuff........
----- Original Message ----- 
From: <odyslim at comcast.net>
To: "Mike Castellana" <rocket_no9 at yahoo.com>; <r-390 at mailman.qth.net>
Sent: Friday, July 29, 2005 8:02 AM
Subject: Re: [R-390] Out from the shadows ...

> The first thing I would do would be to return that re-cap kit.
> There are only 2 or 3 caps in that radio that will ever need to
> be changed. If anybody tells you otherwise, he is a fool.
>
> If you don't feel like rebuilding the electrolytics, you can
> send your old ones to DH distributors and he will rebuild
> them for you for $28.00 each. They will have a different
> can but will work perfectly. 1-888-604-0050. He also
> sells an FP type that is a really good fit for $14.50 .Very minor 
> soldering necessary for the FP
>
> Before you run the radio one moment longer, pull the
> audio deck and replace c609. That is an absolute must.
> Don't use an orange drop. they don't fit well. You can go
> to radioshack and buy a 10uf radial electrolytic that will
> work just fine. If you want to be picky, call Mouser and
> order P/n 75-te1303.3, an 8uf 50 volt aluminum electrolytic.
> The previous owner may have already replaced c609. If
> it is bell shaped and possibly corroded, it is the original.
>
> There are mixed feelings about the re-cap issue. Others
> will tell you something different. Notice paragraph one
> of this note.
>
> I would go for the out of spec resistors if anything.
>
> My flame suit and is on and delete button lubed up :-))
>
> Scott W3CV
> -------------- Original message -------------- 
>
>> How do you do fellas',
>> Mike from Mass here... Recently had the good fortune
>> to find a squeaky clean R-390A of my own. It has an
>> Imperial tag (ser. no. 440) yet everything else on the
>> rig is labeled EAC. (I don't really know where to look
>> for serial nos. on modules) As I mentioned radio is
>> very clean; Engraved front panel is beautiful as is
>> gear train. All WPM shields and covers present.
>>
>> After careful visual inspection of radio combined w/
>> impression radio was taken care of, I double checked
>> fuses and decided to fire it up. I was relieved when I
>> heard the sounds of the airwaves bursting forth into
>> my room. One of the first things I noticed was a
>> fairly obvious hum and vibration from the power
>> transformer (? largest transformer underneath) I
>> pulled both rectifier tubes and radios output tubes
>> but this problem persisted. Before I shut it down I
>> took it up and down the bands; radio seemed sensative
>> everywhere. All functions seemed to be working too.
>> After shutting rig down I pulled both electrolytics
>> ... they both have seepage.
>>
>> I've since received the Field and Depot Maintenance
>> Manual which is fascinating but mostly over my head.
>> I've browsed the Y2K manual (but haven't downloaded
>> yet), read every post to the 390 net in the archives
>> (probably twice:), and spent many many hours checking
>> out what's available on the net. I've also been
>> comparing what I've been learning, with the rig itself
>> on the bench... it's been a blast and is really
>> starting to make sense.
>>
>> Since I'm mostly sure there's nothing tremendously
>> wrong w/ radio my plan of action is to do the absolute
>> minimum to the rig that'll get it up and running and
>> safely. This includes (here's where I'd really
>> appreciate opinions) visual inspection underneath
>> modules, replacing electrolytics, and replacing two
>> nasties in IF module. I'll also be putting a three
>> prong power cord on radio and lubricating gear train.
>>
>> If it isn't obvious enough to y'all I'm very new to
>> this stuff, the only similar project I've tackled has
>> been to completely recap an HRO-60 (mission very much
>> accomplished... I love that National) The only test
>> gear I own is a multimeter. I'd love some advice re-
>> hum from transformer. If after I finish my small list
>> of "do's" and hum is still present what's next?
>>
>> Oh yeah ... I'm awaiting a recap kit and bristol
>> wrench kit ...
>>
>> Please pardon such a long post. I wanted to say hello
>> and let everyone know where I was at and that another
>> of these fine radios had found it's way into some
>> caring hands.
>>
>> Best regards,
>> Mike
>>
>>
>>
>> ____________________________________________________
>> Start your day with Yahoo! - make it your home page
>> http://www.yahoo.com/r/hs
>>
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