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Old 8th Dec 2021, 8:02 pm   #1
G6Tanuki
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Default Magic-Eye life-extension.

One of my Pye PCR receivers has - as well as gaining an internal 240v power-supply - been fitted rather professionally by a previous owner with a Magic Eye tuning-indicator.

It's an ex-Air-Ministry "VI103" - which is the aviator's version of the Y63 or CV1103.

Knowing how these are troubled by loss-of-fluorescence and given that my one still has plenty of green-glow left, I'm pondering how best to preserve it, given that the PCR has now moved to replace an Eddystone 840A as my "Insomniac's special" bedside radio and will probably be racking-up six-hours-a-day {or night} of action.

Would fitting a push-to-enable-the-HT-on-the-target-while-tuning button be sensible? Or would it perhaps be better to fit a 3-position switch: position-1 has heaters and HT off; position-2 powers the heaters; position-3 puts heaters and HT on so it glows??
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Old 8th Dec 2021, 8:17 pm   #2
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Default Re: Magic-Eye life-extension.

I would just temporarily disconnect / remove it if this set is actually being used on a frequent basis, rather that being a display set. Y63s are relatively available as magic eyes go anyway. Fitting switching arrangements means mangling the set further.

It's your radio of course, and hardly rare and exotic unless in pristine WW2 condition.
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Old 8th Dec 2021, 8:19 pm   #3
bigfathairyvika
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Default Re: Magic-Eye life-extension.

It was mine and I wanted the tube to last, then I would either fit a cheap Russian eye or just unplug the tube and tune by ear.
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Old 8th Dec 2021, 8:23 pm   #4
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Default Re: Magic-Eye life-extension.

There was no magic eye in the original PCRs anyway of course. It's unusual for them to be modified in this way - common mods were an S meter and manual RF gain control.
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Old 8th Dec 2021, 8:28 pm   #5
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Default Re: Magic-Eye life-extension.

It's a "working" radio and I want to be able to use it for several hours a day for the next few years...

I have no problems with drilling the front panel to fit a switch; given that it's already acquired an internal mains-transformer/6X4 rectifier, the front-panel power-input is a compression-gland, the two 'headphone' sockets have been replaced by red "Cliff Products" jacks and I've gone through the internals replacing the old waxies and metal-cased-waxies with modern reliable parts. I've also replaced the cathode-resistor of the 6V6 with a 560-Ohm part to throttle-back the HT demand; I only need a Watt or so of audio for night-time listening.

My main interest is prolonging the glowability of the Magic Eye; a bit of research on the popular Internet Tat-Auction site shows Y63 Magic-Eyes to be cheap-and-cheerfully-available for under £20 a time - maybe I should buy a couple and then sit back and watch the 'Pie Chart' on my existing Magic-Eye open and close as it winks me to sleep?:?
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Old 8th Dec 2021, 8:31 pm   #6
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Default Re: Magic-Eye life-extension.

The Y63 may be rather bright in a bedroom with the lights off, at least until it goes dim.

Just pull it!
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Old 8th Dec 2021, 8:45 pm   #7
G6Tanuki
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Default Re: Magic-Eye life-extension.

Quote:
Originally Posted by paulsherwin View Post
The Y63 may be rather bright in a bedroom with the lights off, at least until it goes dim.

Just pull it!
That's part of why I was thinking of a "push-to-tune" feature. It would be kinda appropriate given that I also have low-level military-style 'red-light' illumination in the bedroom [primarily so if I get up in the night to go to the loo I don't tread on the dog].
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Old 8th Dec 2021, 9:57 pm   #8
Alistair D
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Default Re: Magic-Eye life-extension.

Personally I would have fitted a switch to turn off the heater and avoid any kind of cathode poisoning.

In my yet to be published full Hunts CRB3 manual I am suggesting exactly that if the tester is to be used for long periods reforming capacitors.

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Old 8th Dec 2021, 11:33 pm   #9
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Default Re: Magic-Eye life-extension.

Many tape recorders used magic eyes as level indicators, only active on 'record.' My Soundmirror has a very worn head, it's had lots of use - but the EM34 is still bright (heaters are on all the time; HT is on only for record).

So, I'd say break the HT but don't worry about the heaters. Though, if you have a double-pole switch, there's nothing to prevent the other pole doing something with the heater too, such as putting resistance in series for 80% of the running voltage (so warm-up takes a couple of seconds only).
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Old 9th Dec 2021, 8:45 pm   #10
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Default Re: Magic-Eye life-extension.

I would favour a biased miniature toggle switch. That way it could be on (up) off (centre) or momentarily on (down). The eye could be permanently on, off or momentarily on.
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Old 10th Dec 2021, 12:12 am   #11
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Default Re: Magic-Eye life-extension.

I have an AC resistance bridge with an EM34 in it.
The eye sensitivity control is pull on and push off for the eye HT.
The eye is still nice and bright.
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Old 10th Dec 2021, 9:34 pm   #12
G6Tanuki
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Default Re: Magic-Eye life-extension.

Looking at the responses, I'm minded to think that the path-of-least-astonishment is to use a HT-only switch.

Centre-off; up for permanently-on, down [against a bias-spring] for intermittently-on. This will give convenience while also sensibly extending the life of the VI103 glow-bottle's phosphor.
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