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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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6th Aug 2022, 10:09 pm | #1 |
Pentode
Join Date: Jul 2020
Location: Borehamwood, Hertfordshire, UK.
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Pilot Little Maestro T105
Re the dial Bulb can i have help with the replacement of the 10 volt 0.2 Amp MES dial bulb as this is not now available can i use a different one with a resistor shunt as it needs to be quite bright maybe use a led one advice please TAB
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8th Aug 2022, 10:51 am | #2 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,528
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Re: Pilot Little Maestro T105
A common 12V 2.2W automotive instrument bulb could work OK.
The bulb current is actually a dirty mix of 100mA ac plus the dc HT current of the whole set, around 40mA so it shouldn't overload the 2.2W bulb. Otherwise you could bung a 56R 3W resistor in the line, hang a small silicon bridge across it and experiment with LEDs and series resistors!
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8th Aug 2022, 1:23 pm | #3 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,364
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Re: Pilot Little Maestro T105
Well you can get qty 10 x 10v 0.2A here https://www.ebay.co.uk/itm/352161969726 and maybe offer the surplus to other T105 owners on the Forum? Alternatively, if that's too much money, then I would think you'd get away with this 12v 0.2A job without sacrificing too much brightness https://www.ebay.co.uk/itm/152993641737. Jerry
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8th Aug 2022, 1:37 pm | #4 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
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Re: Pilot Little Maestro T105
12V 2.2W LES bulbs are easily and cheaply available from the local car spares shop, I would try one. If it is too bright then a resistor in parallel will dim things a bit.
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8th Aug 2022, 2:04 pm | #5 | |
Dekatron
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Re: Pilot Little Maestro T105
Quote:
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8th Aug 2022, 3:02 pm | #6 |
Dekatron
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Re: Pilot Little Maestro T105
I'm sure that a 12V 0.2A would be fine, though admittedly the pack of ten 10V 0.2A from Germany are the real deal, and with free P&P are good value.
If I'm reading the circuit correctly (someone will soon tell me if I'm not!), although not immediately obvious, the pilot bulb is in the series heater chain - at least in series with one side of the mains. Depending on how the mains plug is wired the bulb might be series with line or neutral. If the bulb fails, the radio will be dead. The total voltage dropped by the hearer chain is 124V. (V1 19v, V2 17V, V3 50V, V4 38V). The heater current is 0.1A. The bulb is rated at 0.2A so will be underrun, which is no bad thing as it will prolong its life. I doubt that the 2V difference of either a 10 or 12V bulb will be noticeable, bearing in mind that the radio will be on the 240V mains tapping, and the mains will probably be a few volts below that. Nice little radios.
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8th Aug 2022, 3:17 pm | #7 | |
Dekatron
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Re: Pilot Little Maestro T105
Quote:
Lawrence. |
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8th Aug 2022, 4:26 pm | #8 |
Pentode
Join Date: Jul 2020
Location: Borehamwood, Hertfordshire, UK.
Posts: 216
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Re: Pilot Little Maestro T105
I have taken the advice of Sideband and ordered 10 from Germany i will keep 5 so any one can have the rest for £1 each + post i also have 5 recovered metal rectifiers for free Ex Ultra Twin. TAB
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8th Aug 2022, 4:38 pm | #9 |
Pentode
Join Date: Jul 2020
Location: Borehamwood, Hertfordshire, UK.
Posts: 216
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Re: Pilot Little Maestro T105
They are a nice radio to work on very well made the service sheet is very basic not a lot of detail shows op valve as UCL82 uses a UCL83 print hard to read but hope to get my one working well.TAB
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9th Aug 2022, 9:12 am | #10 |
Dekatron
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Re: Pilot Little Maestro T105
Later versions did use a UCL83 as a cost reduction exercise. I have had both versions (now sold on). I've never seen the later circuit with UCL83 so be aware that the valve pin connections are different. I think the scale lamp is described as a 'fuse bulb' so probably better to keep the correct type if possible.
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9th Aug 2022, 9:17 am | #11 |
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Re: Pilot Little Maestro T105
...plus the HT current which will add another 50 or so mA to the current so the bulb is probably running at around 150mA give or take.....
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9th Aug 2022, 9:47 am | #12 | |
Dekatron
Join Date: Apr 2011
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Re: Pilot Little Maestro T105
Quote:
Lawrence. |
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