[Boatanchors] restored radio question

[jeremy-ca]

Over/under voltage worries can be taken to extremes.

When in doubt read the manual as many radios are listed as 110-125V 
operation. My 1928 Radiola 18 even has an included 110/120V switch so it can 
be used from 100-130V.

Long term use at 125V will raise internal temperatures and dropping down 
10-12V will usually reduce the current load and heat without applying under 
voltage to the tubes filaments. Check the filament voltages before 
unilaterally dropping the line voltage. Oxide coated cathodes deteriorate 
rapidly when run at more than +/- 5% from design nominal. Use only a true 
RMS reading voltmeter.

However Ive run my SX-62A at 125V for over 4 hours and it didnt run anywhere 
near as hot as I expected. Future long term use will be at 115V or 
thereabouts in order to preserve the transformer insulation a few more 
years. The same procedure for my other radios including the R-390A room 
heater with its own set of annoying heat problems.

AC-DC sets are the ones that particularly need care as they are more prone 
to open filaments. My almost new and 100% original NC-46 always comes alive 
on a variac as I dont need any problems with those 10 tubes and especially 
the PP 25L6's.

Carl
KM1H




----- Original Message ----- 
From: "Donald Sanders" <w4bws at comcast.net>
To: "Gerry Steffens" <gsteffens at pitel.net>; <Boatanchors at mailman.qth.net>
Sent: Wednesday, October 10, 2007 12:15 PM
Subject: Re: [Boatanchors] restored radio question


> Gerry, you can operate the radios in banks from a
> reduced power source. Instead of a variac, I have
> a transformer with two 6.3 volt 10 windings that
> I wired with the secondaries in series with the 125
> vac. The first winding goes to the top of a duplex
> outlet and the second winding goes to the bottom
> contacts. This allows me to run the radios at
> 125 - 6.3 on one outlet and 125 - 12.6 on the other
> outlet.
> I use a multiple outlet strip from each outlet
> and place the oldest radios on the lowest voltage.
> Using a 4 inch outlet box and a plate with the duplex
> outlet and a on/off switch I can control the whole
> bank from one switch. I only run them when I am
> present and I mounted a smoke detector over the
> radios. This allows me to work in the shop and have
> them working.
> BTW, I use a long wire antenna into a preamp into a
> 4 way cable splitter and then coax to each of 4
> receivers so I can listen to 4 frequencies at once.
> I monitor the most active AM freqs on 160, 80, 40,
> and 20 plus a couple shortwave stations that I like.
> Naturally I use my favorite receivers for this effort.
>
> The others I turn on and run them about 2 days a week
> for 4 to 6 hours total. They are in an air conditioned
> shop and I have not had a failure in a couple years.
> Though I have had a couple tubes that needed replacement
> due to "age". I have a modest 8 receiver collection, was 15,
> that I am weeding out for adoption in new loving homes.
>
> My enjoyment has been returning them to operational
> status, using them a while, and then replacing them with
> a new project.  I still like to use my 75S3 and SX100 for
> my station.
> I hope this helps.
>
> Healthfully yours,
>                          Don W4BWS
> ----- Original Message ----- 
> From: "Gerry Steffens" <gsteffens at pitel.net>
> To: <Boatanchors at mailman.qth.net>
> Sent: Tuesday, October 09, 2007 9:05 PM
> Subject: [Boatanchors] restored radio question
>
>
>> OK Anchorites, what do you think about the following?
>>
>>
>>
>> I have approaching 300 radios in the collection.  Many work fine to
> adequate
>> for now.  Many others have been fully restored.  Hopefully, more will be
>> restored after retirement in a few years.
>>
>>
>>
>> How often and for how long per session should these functioning radios be
>> turned on and used to preserve their functionality?
>>
>>
>>
>> Gerry
>>
>>
>>
>>
>>
>> _______________________________________________
>> Boatanchors mailing list
>> Boatanchors at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/boatanchors
>> ** List Administrator - Duane Fischer, W8DBF/W9WZE **
>> ** For Assistance: dfischer at usol.com **
>> $ For vintage radio info, see the HCI web site $
>> http://www.w9wze.net
>>
>>
>
>
> _______________________________________________
> Boatanchors mailing list
> Boatanchors at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/boatanchors
> ** List Administrator - Duane Fischer, W8DBF/W9WZE **
> ** For Assistance: dfischer at usol.com **
> $ For vintage radio info, see the HCI web site $
> http://www.w9wze.net
>
>