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

Fri Jul 29 09:20:36 EDT 2005

Absolute MUST:  Replace the Filter Killer Cap. IF deck, C-553, 
originally .01 ufd at 300 vdc, blocks DC to the mechanical filters. It 
is a known weak component. It if fails, it will destroy one or more of 
your IF filters. Replace with a modern .01 600V orange drop.  See 
http://www.militaryradio.com/R390AMaintenanceTasks.pdf and others.

----- Original Message -----
From: odyslim at comcast.net
Date: Friday, July 29, 2005 9:02 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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