Leak Festoon Lamps

[Linnovice]

Hi all. I have a Leak Stereofetic Tuner in which the scale/meter lamp has failed. It states in the handbook that it shouldn’t be run for extended periods without this lamp (curious) but I can’t see any reference as to what this lamp is.
So my question is what is its value and where can I get a replacement. On the Troughline schematic it shows a 6V 2W lamp, is the Stereofetic the same? If it is I’ve searched the internet but can’t find a replacement.
I’m a bit stuffed now so any help would be most welcome.
Mike

[TrevorG3VLF]

What is the circuit? If there are components in series, then voltages could be wrong if the lamp is missing. Doubtless a different bulb or led with resistor compensation could be used.

[snowman_al]

You may have difficulty getting the correct wattage...
It was covered before here: https://www.vintage-radio.net/forum/...ad.php?t=66231

The manual says the reason for not using it without the bulb is it over volts the 2 1000uF smoothing caps C1 and C2. End of section 1 here: http://www.magafox.com/tubeamps/Leak...%20SERVICE.pdf
Surely it would be easy enough to replace them with modern 16 or 25 volt 1000uF axial caps. Then make up an LED replacement for the 'bulb'?

Unless anyone comes back to say it is okay, I would not recommend using a 6 volt 3 watt or higher wattage type.

[Linnovice]

The unit was recapped a couple of years ago. The 1000uF are now 40V capacitors. I have some 8V 100mA axial bulbs (spares for Teac VU meters). Could I use one of those and solder it in?

[snowman_al]

Originally Posted by Linnovice

The unit was recapped a couple of years ago. The 1000uF are now 40V capacitors.

So- no problem running the caps over voltage!

Originally Posted by Linnovice

... I have some 8V 100mA axial bulbs (spares for Teac VU meters). Could I use one of those and solder it in?

Let's go back a step, the original lamp was 6 volts at 2 watts. That equates to a current of 0.33A or 330mA. So yes you could run up to 3 in parallel.

But here is another idea. 12 volt festoon bulbs are readily available (for cars) and come in 3 and 5 watt sizes. If you use them on 6 volts they are not as bright, but also draw less current. I've just tried a couple of 12 volt bulbs at 6 volts and a 3 watt bulb takes 180mA and a 5 watt bulb takes 275mA. Both within the limit of the transformer, only question would be if they give enough light output for you. You could try it for very little cash though.

Alan

[Linnovice]

Hi Snowman,

Yes, I did the sum also. I’ve swapped in the 8V 100mA and one is fine. It seems adequately bright enough. The tuner has been in on for the past 3hours and it’s working fine.