[R-390] Standy or Off?

[Bob Camp]

Hi

My preference would be for most radios to be turned off. Having 
something "smoke off" out here in the country with nobody home is an 
*expensive* sort thing. That has nothing to do with what's best for the 
radio.

There is no doubt in my mind that the radios work better after a few 
hours of warm up. There is also no doubt in my mind that ballast tubes 
mostly go from power cycling or vibration. They love to be on all the 
time in a fixed environment.

If you are going to run a radio 24/7 there are a few things to be 
careful about:

1) The RFI filter is ahead of the fuse. It's well worth the effort to 
check it out carefully. The only thing protecting it the breaker box.

2) The line cord is a hand wired part on most of these radios. Make 
sure that the hot and neutral are correctly wired. The fuse and line 
switch should be in series with the hot lead rather than the neutral 
lead.

3) I must admit that not every fuse in the known universe is in stock  
in the basement. From time to time substitutions get made. Check both 
the fuses in the radio to be sure they are both the correct type and 
rating (no 32 volt DC fuses allowed ...). If the ovens are turned off 
on the radio the line fuse can be dropped in value from the normal 
listed value. This is a *very* good idea in this case.

4) Think about what happens if a part cooks out. Setting the radio on a 
box of reloading supplies probably isn't a real good idea. Properly 
spacing it out in a metal rack away from walls and furniture probably 
is a good idea.

5) Check the electrolytics in the power supply. They have enough energy 
associated with them that they can be a problem if they go out. 
Fortunately they normally just drop in value rather than short out. 
When they get very leaky they will start to get hot and that's not 
good.

6) Think about where the smoke detector and radio are located (you *do* 
have a smoke detector in the radio room don't you?). Most smoke rises 
....

I will admit that in most cases this is much to do about nothing. 
R-390's do not burst into flames on a regular basis. The power 
transformers in them seem to be reliable and even if they do go the 
metal can is a pretty good fire barrier. Of course there is the smell.

Speaking of the smell. The rectifier that drives the antenna relay is 
an issue. They are known to fail and when they do they both smell bad 
and the stuff is bad for you to breathe. If your radio still has an 
original rectifier in it you have a classic dilemma. Do you *really* 
want to replace a perfectly good working part? In general that's not a 
good idea. If you don't and it goes with nobody home - wow ...

If you run the radio 24/7 then at least disconnect the antenna during 
thunder storm season. R-390's are rugged radios., but RF transformers 
simply were not designed to take the kind of energy a near by lightning 
hit induces in an antenna. With a direct hit, well that's why we have 
home insurance ....

One good thing about 24/7 operation. A warm radio is a dry radio. A lot 
of the strange problems in components are related to humidity issues. 
If you are in a high humidity area this could be a significant issue.

Another thing about 24/7 operation - you are more likely to *use* the 
radio. This also is a very good thing.

	Take Care!

		Bob Camp
		KB8TQ








On Feb 26, 2005, at 7:54 PM, charles bolland wrote:

> Hi all,
>
> I've burnt out a couple of Ballast tubes over the months and I am a 
> little
> "gun" shy now.  I don't want to ware out other tubes in my set, so I am
> wondering which will prolong the life of any tubes in my receiver best 
> of
> the three following options?
>
> 1. Completely off when not in use - thinking about turning the set on 
> and
> off all of the time.
> 2. Standby when not in use - thinking some tube still burning all of 
> the
> time.
> 3. On when not in use - thinking all of the tubes are hot all of the 
> time.
>
> Any comments will be appreciated.
>
> Chuck
>
>
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