Pilot Little Maestro pilot lamp

[petervk2mlg]

While looking at the service data for the Pilot Little Maestro 444 I noticed that it specified a 7.3 volt pilot lamp. Is this a mistake or were 7.3 volt lamps available at the time (1939)?

[Sideband]

There were some odd voltage lamps around at the time and some of them were miniature bayonet. Somewhere in a box of unsorted stuff I have from years ago there are some 7.5 volt miniature bayonet types. If I can find them I'll put them aside for you. As to the current rating, I have no idea but should be easy to check.

[vidjoman]

I suspect that it was originally an available lamp meant for a motorcycle with a 6 volt battery just as 14 volt bulbs were common in cars with a 12 volt battery before better voltage regulators became available.

[emeritus]

If you are contemplating changing the lampholder I have some Lucas 8V 0.15A MES bulbs that might do. I bought a box of them in Proops many moons ago and have never found anything that needed bulbs of this voltage rating.

[vidjoman]

Originally Posted by emeritus

If you are contemplating changing the lampholder I have some Lucas 8V 0.15A MES bulbs that might do. I bought a box of them in Proops many moons ago and have never found anything that needed bulbs of this voltage rating.

I thought that these radios had series heaters and therefor the current is more important than the voltage as long as the voltage is 'near enough'.

[emeritus]

True: if it is in a series chain, then any 0.25A (or slghtly higher, but not lower) current rated bulb of a similar low voltage ( 3 - 12V ) should do at a pinch.

[winston_1]

Mine has an (original) 7.25V 0.25A bulb. It is not totally in series with the heaters, it has a parallel shunt (part of the line cord).

[kestrelmusic]

The point about this one is that it forms part of the heater chain, and is in parallel with a section of the heater dropper which is contained in the line cord. The section of the dropper in parallel with the dial lamp is 15 ohms.

Is your line cord dropper still there and in reasonably good condition?

These are sweet little sets and perform remarkably well for such a simple circuit.

[petervk2mlg]

Many thanks for all the responses. Actually the radio isn't mine. I just saw it listed for sale here in Australia and was interested enough to look up the service data. The line cord was missing and someone had bolted some power resistors in an insulated box at the back of the chassis to drop the volts.

[petervk2mlg]

Here is a pic of the addition

[kestrelmusic]

Originally Posted by petervk2mlg

Here is a pic of the addition

<<shudder>>

[turretslug]

An unearthed greenhouse heater, with a radio as a bonus!

I suppose that long ago that would be politely described as a "workmanlike repair", nowadays the response would be more along the lines, "How will I explain this to the magistrate?"

An unearthed greenhouse heater, with a radio as a bonus!

There is a lot to be said about unearthed stuff with enough clearance/creepage, you can't get a shock from it! As to

"How will I explain this to the magistrate?"

I am waiting for the court case about a mains socket having (surprise) mains on it and shocking someone.