|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
View Poll Results: Will the radio work when turned on at 4PM? | |||
YES | 2 | 10.00% | |
NO | 18 | 90.00% | |
Voters: 20. You may not vote on this poll |
|
Thread Tools |
6th Nov 2021, 1:12 pm | #41 | |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
Quote:
|
|
6th Nov 2021, 1:18 pm | #42 | ||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Cheers.
__________________
Help!! I've been electrocuted by a glass thing that glows |
||
6th Nov 2021, 1:26 pm | #43 | |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Pilot Little Maestro restoration project.
Quote:
https://www.vintage-radio.net/forum/...6&d=1636039756 ? Lawrence. |
|
6th Nov 2021, 1:30 pm | #44 | ||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Cheers.
__________________
Help!! I've been electrocuted by a glass thing that glows |
||
6th Nov 2021, 1:58 pm | #45 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
It looks as though the pilot lamp wiring has been altered as V3 (6Q7G) was the last valve in the chain with one side connected to chassis. Where does the other side of the pilot lamp go? It may be going to chassis via the holder and there may or may not be a shunt resistor across the pilot lamp.
|
6th Nov 2021, 2:03 pm | #46 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Jay
__________________
Help!! I've been electrocuted by a glass thing that glows |
|
6th Nov 2021, 2:10 pm | #47 | ||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
__________________
Help!! I've been electrocuted by a glass thing that glows |
||
6th Nov 2021, 2:15 pm | #48 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Pilot Little Maestro restoration project.
Where did the right hand Red wire shown in the photo in the link I posted connect to apart from tag 6 of the output valve socket and one end of the 50 Ohm resistor?
Lawrence |
6th Nov 2021, 2:20 pm | #49 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
The answer to that is i'm not sure, Since been snipped off, In hind sight not a good idea
__________________
Help!! I've been electrocuted by a glass thing that glows |
6th Nov 2021, 2:27 pm | #50 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
The red wires had been taped on to the original cord or at least it looked like the original cord or what was left of it, Wanted it gone asap due to any asbestos risks
__________________
Help!! I've been electrocuted by a glass thing that glows |
6th Nov 2021, 3:24 pm | #51 |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Looks like the 50 ohm resistor is in series with the mains input and the heater of the 25Z4 rectifier
__________________
Help!! I've been electrocuted by a glass thing that glows |
6th Nov 2021, 5:31 pm | #52 | ||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Believe the above to be correct after a bit of googling valve pinouts and testing various points of the circuit, Quote:
Yea short goes away when the band selector is switched S4 Shunts one of the coils to ground which appears as an almost DC Short
__________________
Help!! I've been electrocuted by a glass thing that glows Last edited by Radio Scotland; 6th Nov 2021 at 5:39 pm. Reason: correction |
||
6th Nov 2021, 5:39 pm | #53 | ||
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
Quote:
Just seen the post above, I think you meant the pilot lamp goes to V3 heater from your description earlier. Last edited by Simon Gittins; 6th Nov 2021 at 5:44 pm. Reason: Addition. |
||
6th Nov 2021, 5:42 pm | #54 | |||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
__________________
Help!! I've been electrocuted by a glass thing that glows |
|||
6th Nov 2021, 5:46 pm | #55 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
That's good. You may want to try it with and without a shunt when you get it going.
|
6th Nov 2021, 5:51 pm | #56 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Currently waiting on a new audio coupling cap and 2 x smoothing caps. Cheers jay
__________________
Help!! I've been electrocuted by a glass thing that glows |
|
6th Nov 2021, 7:03 pm | #57 | ||
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
Quote:
Yea my mistake lamp is in series with V3 Heater
__________________
Help!! I've been electrocuted by a glass thing that glows |
||
6th Nov 2021, 7:46 pm | #58 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
The 15 ohm 2.5 watt resistor you suggested should be fine.
The heater chain current is 0.3A and the resistor should be able to handle this current if the bulb fails; the wattage is the current squared times the resistance which works out at 1.35W. |
6th Nov 2021, 7:56 pm | #59 | |
Heptode
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 671
|
Re: Pilot Little Maestro restoration project.
Quote:
One last thing (i think) Which of the following capacitors would it be advisable to change ? Obviously C10 Audio coupling for starters..And C13/14 Smoothing caps Wont touch anything frequency related unless need be, Cheers
__________________
Help!! I've been electrocuted by a glass thing that glows Last edited by Radio Scotland; 6th Nov 2021 at 8:12 pm. |
|
6th Nov 2021, 9:01 pm | #60 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 501
|
Re: Pilot Little Maestro restoration project.
Yes, C10 is the most important one. C13 and C14 might be reformed but changing them is an option. C15 is worth changing (it needs to be a Class X type as it's filtering the mains) also C12 as if it fails the output transformer is at risk.
We normally suggest not changing too many capacitors at once as it's easy to make a mistake so you could try the set after changing those five and then change others as required. At some point C1 should be changed in case someone touches the end of the throw-out aerial (needs to be a Class Y type). C6 will probably reduce the screen voltages and C4 will probably mean the AGC won't work properly. C11 will probably be causing low volume. C5, C7, C8 and C9 could cause trouble as well. |