[R-390] ballast tube

Sat Nov 28 14:31:50 EST 2020

I had the same problem that Paul had. The result was 2 ballast tubes
damaged.

Eventually I substituted the ballast with a solid state device that  is
sold on ebay and hope the problem is solved for a long time.

But the problem makes me wonder about why a military grade receiver that is
intended to be working on tracks and ships  is so fragile. In my experience
(short) this is the only tube that is so weak and has no  tolerance to
light impacts when the filament is still warm.

Regards,
Jose
EA8DCP

El sáb, 28 nov 2020 a las 17:09, <r-390-request at mailman.qth.net> escribió:

> Send R-390 mailing list submissions to
>         r-390 at mailman.qth.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://mailman.qth.net/mailman/listinfo/r-390
> or, via email, send a message with subject or body 'help' to
>         r-390-request at mailman.qth.net
>
> You can reach the person managing the list at
>         r-390-owner at mailman.qth.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of R-390 digest..."
>
>
> Today's Topics:
>
>    1. Re: Parts (Cecil)
>    2. Re: The R-390 and R-390A bridge rectifier (Fred Moore)
>    3. Anyone have a spare ballast tube? (Paul Staupe)
>    4. Re: Anyone have a spare ballast tube? (Larry H)
>    5. Re: Anyone have a spare ballast tube? (Jacques Fortin)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 11 Nov 2020 17:38:22 -0600
> From: Cecil <chacuff at cableone.net>
> To: R-390 at mailman.qth.net
> Cc: Collins R-390 HF Receiver List <r-390 at mailman.qth.net>
> Subject: Re: [R-390] Parts
> Message-ID: <EEA8F4DA-E97A-4615-B80A-095D2ED21D44 at cableone.net>
> Content-Type: text/plain; charset=utf-8
>
> I have decided to list this stuff on the auction site as my time permits
> over the winter months. If interested keep an eye out for it there....if
> not the delete key is in order.
>
> Thanks,
>
> Cecil
> K5DL
>
> Sent from my iPad
>
> > On Nov 9, 2020, at 10:36 AM, Cecil <chacuff at cableone.net> wrote:
> >
> > ?On a bit of a fishing trip here but wanted to see if there is any
> interest in R-390A parts.
> >
> > Going through and cleaning out and have an assortment of stuff that I
> will need to move in the next couple months.
> >
> > What I don?t have are original meters, knob sets, top and bottom covers,
> Utah plates. Already traded all those for another radio I had interest in.
> >
> > Also if you are doing restoration work on a larger scale and want to
> make a deal on all this stuff...contact me off list and we will work
> something out.
> >
> > I just can?t lift, work on or ship 100+lb radios anymore.
> >
> > Thanks folks!
> >
> > Cecil Acuff
> > K5DL
> >
> > Sent from my iPad
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 18 Nov 2020 19:31:43 -0000
> From: "Fred Moore" <fred_moore at usa.net>
> To: Norman Ryan <nnryann at yahoo.com>, <fred_moore at usa.net>
> Cc: Collins R-390 HF Receiver List <r-390 at mailman.qth.net>
> Subject: Re: [R-390] The R-390 and R-390A bridge rectifier
> Message-ID: <072ykRTEr9184Set.1605727903 at web02.cms.usa.net>
> Content-Type: text/plain; charset=utf-8
>
> I am using the following diode to replace the copper oxide bridge
> underneath
> the R-390 power supply.  I fits nicely and has a mounting hole in the
> case.
> The same part can be used to replace the R-390A selenium thing.
>
> 4A 400piv.
> Digikey GBU404DI-ND
> MFR: GBU404
>
> -Fred
>
> ------ Original Message ------
> Received: Sat, 26 Sep 2020 06:26:02 AM GMT
> From: Norman Ryan via R-390 <r-390 at mailman.qth.net>
> To: fred_moore at usa.netCc: Collins R-390 HF Receiver List
> <r-390 at mailman.qth.net>
> Subject: Re: [R-390] The R-390A IF transformers internal resistors.
>
>  Hi, all,
> The schematic shows the IF coil resistors but not their values which leads
> me
> to suspect those resistors are selected based on each winding's
> characteristic.
> Is it feasible to try varying sizes and choose the ones that perform best??
> Looking around my shop I've seen 39K and 47K resistors -- 47K being the
> most
> often encountered.
> Absent a way to test, would it put a harelip on God's plan for salvation
> if we
> simply install 47K resistors and let it go at that?
> 73Norman
>
>     On Saturday, September 26, 2020, 1:27:05 AM EDT, Roy Morgan
> <k1lky68 at gmail.com> wrote:
>
>  Jacques,
>
> I don?t have info on the values of the resistors, but I do have a guess:
>
> Those resistors are there to ?spoil the Q? of the IF transformers, and in
> general widen the passband.? It could be that in the two other radios you
> tell about, the different manufacture coils have slightly different winding
> resistance and thus need different parallel resistors to get the desired
> bandpass.
>
> Indeed, there were articles that suggested removing those resistors to
> ?make
> the radio hotter?.? It was of course bad advice, and the resulting changes
> in the actual performance were both un-necessary and bad.
>
> Note: in the MIT Radiation Laboratory series volume on ?Vacuum Tube
> Amplifiers? by Valley and Wallman, Volume 18, there is an extensive
> explanation of the engineering involved in bandwidth control in amplifiers
> -
> as applied to radar IF amplifiers (presumably mostly 30 mc).
>
> The entire 28 volume set is available in PDF form here:
> https://www.febo.com/pages/docs/RadLab/
>
> Roy
>
> > On Sep 25, 2020, at 11:14 AM, Jacques Fortin <jacques.f at videotron.ca>
> wrote:
> >
> > Hi all,
> >
> > I am still working on the last R-390A that followed me home. ... that a
> previous
> > "owner" removed all the resistors within the IF transformers.
> >
> > The windings test all OK and the caps looks like the original ones, so it
> > may have been an attempt to "boost" the IF gain.
>
> Roy Morgan
> K1LKY since 1958
> k1lky68 at gmail.com
>
>
>
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 26 Nov 2020 14:11:58 -0600
> From: Paul Staupe <staupe at gmail.com>
> To: r-390 at mailman.qth.net
> Cc: Collins R-390 HF Receiver List <r-390 at mailman.qth.net>
> Subject: [R-390] Anyone have a spare ballast tube?
> Message-ID:
>         <
> CAOQ84atOZLxNYROpkEA6aSQE3uH5kjqPFyTfqiqzBvtu3EWMcw at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> I made the mistake of moving my Collins non-A into its cabinet with the
> filaments still warm and lost my ballast tube.  Anyone have a spare?
>
> I was using the one out of my EAC R-390A when I went to a solid state unit
> that's sold on eBay.... for some reason the non-A didn't like it but the
> EAC didn't mind.  Anyone else have that issue?
>
> Happy Thanksgiving everyone!
>
> Paul
> Minnesota
>
>
> ------------------------------
>
> Message: 4
> Date: Fri, 27 Nov 2020 20:16:09 -0800
> From: Larry H <larry41gm at gmail.com>
> To: Paul Staupe <staupe at gmail.com>
> Cc: Collins R-390 HF Receiver List <r-390 at mailman.qth.net>
> Subject: Re: [R-390] Anyone have a spare ballast tube?
> Message-ID:
>         <
> CAOSJ_nta-4b8_44pSjHGF0Ab23ckzNDVmQPJVXkFF9O2eMhw7A at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Hi Paul,  Sorry, I don't have a spare for you.  However, a very common
> substitute is a 12bh7 or 12by7, etc, if your ac power does not fluctuate
> much.  Most places are steady enough for them.  The thing is that they
> require a simple mod to the filament connections to use them.
>
> Happy Holidays to all.
>
> Regards, Larry
>
> On Thu, Nov 26, 2020 at 12:13 PM Paul Staupe <staupe at gmail.com> wrote:
>
> > I made the mistake of moving my Collins non-A into its cabinet with the
> > filaments still warm and lost my ballast tube.  Anyone have a spare?
> >
> > I was using the one out of my EAC R-390A when I went to a solid state
> unit
> > that's sold on eBay.... for some reason the non-A didn't like it but the
> > EAC didn't mind.  Anyone else have that issue?
> >
> > Happy Thanksgiving everyone!
> >
> > Paul
> > Minnesota
> > ______________________________________________________________
> > R-390 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/r-390
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:R-390 at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
>
>
> ------------------------------
>
> Message: 5
> Date: Sat, 28 Nov 2020 12:09:12 -0500
> From: "Jacques Fortin" <jacques.f at videotron.ca>
> To: "'Collins R-390 HF Receiver List'" <r-390 at mailman.qth.net>
> Cc: 'Larry H' <larry41gm at gmail.com>,    Collins R-390 HF Receiver List
>         <r-390 at mailman.qth.net>
> Subject: Re: [R-390] Anyone have a spare ballast tube?
> Message-ID: <[email protected]>
> Content-Type: text/plain;       charset="US-ASCII"
>
> Hi Paul,
>
> Fair Radio still have NOS 3TF7 ballast tubes in stock.
> Or if you can find a 2HTF11B, it will be good also (this is the original
> type used in the R-390s).
> If the price asked is too much, just strap pins 2 and 4, then pins 5 and 7
> of the 3TF7 socket and use either a 12BY7 or a 12BH7 in there.
> No need to be a "good" tube, as far as the filaments are still good...
>
> 73, Jacques, VE2JFE
>
>
>
> ------------------------------
>
> _______________________________________________
> R-390 mailing list
> R-390 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>
>
> End of R-390 Digest, Vol 199, Issue 2
> *************************************
>

<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Libre
de virus. www.avast.com
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>