6th Aug 2018, 6:42 pm | #21 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: Pilot T105
If you need any info on these sets, voltage comparisons etc feel free to ask as I have just repaired one of these and replaced quite a few components in the process. Check the mains dropper resistor isn't shorting to chassis somewhere. I had a wire touch the metalwork and it blew the bulb violently. It gave me a bit of a fright in the process!
Alan. |
6th Aug 2018, 7:30 pm | #22 |
Heptode
Join Date: Jan 2018
Location: Folkestone, Kent, UK.
Posts: 709
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Re: Pilot T105
Yes thanks for the info, there doesn't seem to be any problem there, just low volume.
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6th Aug 2018, 7:39 pm | #23 |
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Join Date: Feb 2004
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Re: Pilot T105
The UCL83 on mine had low emission. Check the voltage across the cathode resistor on the audio output pentode section. If this is low the valve may be past its best. They are cheap enough to replace.
Alan. |
6th Aug 2018, 8:10 pm | #24 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,549
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Re: Pilot T105
Did you check the anode load of the triode section of the UCL83? They go high and will cause low volume. Also the common screen grid feed to the mixer and IF amp.
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There are lots of brilliant keyboard players and then there is Rick Wakeman..... |
7th Aug 2018, 11:39 am | #25 |
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Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
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Re: Pilot T105
Probably a bit late to mention it, but it might be helpful to newcomers to understand why the bulb blew in the first instance due to the .05µF capacitor C27 being short circuit. On the annotated drawing, the red line shows how the pilot bulb acts as a fuse in such circumstances. In a series heater chain, all the valve heaters must pass the same current - in the case of the T105, 0.1A (100mA), but may, and usually do, have different voltages as shown on the part circuit of the T104 below. Though the heaters are rated at 0.1A, the bulb is rated at 0.2A, presumably to reduce the chance of it blowing due to a surge when the radio is switched on.
Nice little sets. The cabinet is brown Bakelite, but when they were introduced in 1956, it was a time when gaudy colours were becoming fashionable, and I guess that's why Pilot sprayed the sombre brown cabinets a gaudy blue, with gold embellishments. When I bought mine, I thought it was a DIY paint job, but later discovered it was a factory finish, so I got an aerosol colour matched to suit. Below are before and after pics. To my mind, one of the nicest features of the many 'Little Maestro' sets, is the quality of their dials. An aspect of radios that interests me, and maybe others too, is where they fit into our social history. They were an expensive acquisition in the austere mid 50s - a time when few homes could afford more than one radio, hence, like many small sets, the 'T105' was described as 'Transportable' meaning that as it had an internal aerial, it could be taken from room to room if desired, and they often were. (The other option being extension speakers). Quite a lot of sets of that era - the Stella 105U for example - had a handle styled into them for that reason. No relevance to this thread, but I've added a pic below to show what I mean. Hope that's of interest.
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David. BVWS Member. G-QRP Club member 1339. |
7th Aug 2018, 11:49 am | #26 | |
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Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Pilot T105
Quote:
Lawrence. |
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7th Aug 2018, 2:48 pm | #27 |
Heptode
Join Date: Jan 2018
Location: Folkestone, Kent, UK.
Posts: 709
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Re: Pilot T105
Have tried another UCL83 and things have improved somewhat, will order a new valve and take it from there.
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11th Aug 2018, 9:44 am | #28 |
Heptode
Join Date: Jan 2018
Location: Folkestone, Kent, UK.
Posts: 709
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Re: Pilot T105
I'm pleased to say that after changing all the wax caps and fitting a 12 volt 0.25A dial lamp the T105 is now back working as it should be.
Thanks to all for the valuable advice, will attempt to post pics ASAP. |
11th Aug 2018, 3:26 pm | #29 |
Heptode
Join Date: Jan 2018
Location: Folkestone, Kent, UK.
Posts: 709
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Re: Pilot T105
Picture now attached of finished T105
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11th Aug 2018, 7:40 pm | #30 |
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Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: Pilot T105
A nice little set. Makes mine look a bit grubby. I might treat it to a new coat of paint.
Alan. |