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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
View Poll Results: Will the radio work when turned on at 4PM? | |||
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Voters: 20. You may not vote on this poll |
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14th Nov 2021, 5:49 pm | #161 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
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Re: Pilot Little Maestro restoration project.
Quote:
Frustrating having to wait on another dropper cap coming in the post Out of desperation i paid 50p extra for first class postage Cheers Jay
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14th Nov 2021, 6:30 pm | #162 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
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Re: Pilot Little Maestro restoration project.
Hi Jay, if you can achieve 75volts at the top of the heater chain, then everything will be in order. In fact spot on if the dial light is a 6.3 volt bulb.
Assume the valve line-up is 6A8G alt 6K8G, 6K7G alt 6U7G, 6Q7G, 25A6 or alt 25L6 and 25Z6. DFWB. Last edited by FERNSEH; 14th Nov 2021 at 6:39 pm. |
14th Nov 2021, 6:34 pm | #163 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
If i get close i'll be happy Cheers
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14th Nov 2021, 6:56 pm | #164 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
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Re: Pilot Little Maestro restoration project.
In reality, a few volts either way for the heater supply won't make a lot of difference. Remember when these sets were built, they didn't have a mains voltage tap and were rated 200 - 250V without adjustment. At the low end of mains, the valves would have been under run. At 240 - 250V, they would have been running normally. it's likely that for 90% of their use, the valves would have been slightly under run.
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14th Nov 2021, 7:32 pm | #165 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
Jay
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14th Nov 2021, 7:57 pm | #166 |
Heptode
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Re: Pilot Little Maestro restoration project.
Does anybody think this will actually work first time when the heaters & HT Supply is sorted out ?
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14th Nov 2021, 8:59 pm | #167 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,171
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Re: Pilot Little Maestro restoration project.
Probably a very high chance of success; worst case it will only damage 1 valve but without one of us testing it we have no way of knowing.
You could try running on a lamp limiter or variac at reduced voltage. Measure heater string volts and then volts into set. They should be in the proportion of 75/240 of whatever voltage you are applying Ed |
14th Nov 2021, 9:09 pm | #168 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
If the valves are good and theres no coils/inductors open or shorted, Then it should sing again. Just found a red 60w bayonet bulb, The type for a log effect fire and a 100w screw in, But no socket for it. Jay
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14th Nov 2021, 9:45 pm | #169 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
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Re: Pilot Little Maestro restoration project.
I've just been in the 'mancave' and tried the Pilot Model 10 that I converted to capacitor dropper around 12 years ago. All still good so I thought I'd show you how I did mine. I used a capacitor from an old florescent fitting which was a 2.6uF at 400Vac which was pretty much spot on for the value I needed. When I measured it however is was slightly low at 2.4uF. When fitted, the radio worked well but was a tad low on heater voltage so I fitted a couple of 0.1uF caps in parallel and put them in parallel with the 2.6uF to bring the value up and I was happy with the result. I subsequently replaced the two 0.1uF caps with a single 0.22uF cap at 300Vac which fitted much more neatly into the available space.
I used the original dropper mounting cage with some shrink-sleeving which made a snug fit into the space. Well it's been OK for the last 12 years with moderate use. The last one just shows the mains voltage at the time which is a tad under 240V.
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14th Nov 2021, 9:59 pm | #170 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
Like i say iv'e never worked on a valve set before or really done any restoration work on a radio, But learning plenty from this thread, Does anybody know the working wattage of this radio ? I'm thinking around 40 watts. Cheers
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14th Nov 2021, 11:12 pm | #171 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
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Re: Pilot Little Maestro restoration project.
Well unless it's stated in any of the service literature or (sometimes) printed on the back of the radio, then 40W is a fair guess. Your set uses 300mA valve heaters whereas mine uses 150mA heaters. According to my power meter mine is running at around 28W so I suppose if you were to double that to 56W it probably won't be far out.
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14th Nov 2021, 11:17 pm | #172 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
Jay
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15th Nov 2021, 2:51 pm | #173 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Trying to find small enough bolts to mount the HT Resistor isn't easy
Its a job for the dremel
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15th Nov 2021, 5:50 pm | #174 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
''Bodged in''
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15th Nov 2021, 7:26 pm | #175 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
I'm confused. In the pic below is the way the rectifier socket is wired, White wire is the anodes, Piece of solder is the cathodes. I Have a 25Z4G Rectifier, Radio calls for a 25Z6G.
But the socket doesn't looked as if its wired for either of them, I'm probably missing the obvious, Been a long day. Jay
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15th Nov 2021, 7:35 pm | #176 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Pilot Little Maestro restoration project.
The socket in the photo is wired for either so far as I can make out, 3&5 are connected together (anode(s)) and 8&4 are connected together (cathode(s)) Numbered anticlockwise in the socket photo starting with number 1 which is the first to the right of the keyway for the spigot, the first to the left of the keyway being number 8.
Lawrence. Last edited by ms660; 15th Nov 2021 at 7:46 pm. Reason: extra info |
15th Nov 2021, 7:48 pm | #177 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
Thanks Jay
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15th Nov 2021, 8:08 pm | #178 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
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Re: Pilot Little Maestro restoration project.
Some of the side contact valves were numbered anticlockwise as viewed from underneath, eg:
https://frank.pocnet.net/sheets/030/e/ECH3.pdf Lawrence. |
15th Nov 2021, 8:41 pm | #179 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
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Re: Pilot Little Maestro restoration project.
Quote:
I have a metal temperature probe on my DMM,Was wondering if i could use it to monitor the temp of the HT resistor ? Keeping in mind chassis is hooked to neutral.. Jay
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15th Nov 2021, 8:51 pm | #180 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
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Re: Pilot Little Maestro restoration project.
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