UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Reply
 
Thread Tools
Old 21st Sep 2022, 8:07 pm   #21
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,194
Default Re: My Latest Junker

Mistweaked aerial trimmer?
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline   Reply With Quote
Old 21st Sep 2022, 8:59 pm   #22
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker

I was probing the detector diode and accidently broke one of the legs, Replaced it and she burst into life, The original Diode either had a weak output or a bad solder joint.


Would never have suspected that was the issue, Pity i spent ages recapping it But most were out of spec anyway,


Pretty sure shango066 was caught out with this too after spending ages trying to find the cause of low volume,
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 9:31 am   #23
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Anybody know how you adjust the pre-set on this ?
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 10:58 am   #24
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 16,488
Default Re: My Latest Junker. Courier AM Car Radio.

Aerial trimmer?
Nickthedentist is offline   Reply With Quote
Old 22nd Sep 2022, 11:00 am   #25
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by Nickthedentist View Post
Aerial trimmer?
No it's not that nick, Presume it must be one of the inductors either side of the preset switch
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 1:20 pm   #26
rambo1152
Dekatron
 
rambo1152's Avatar
 
Join Date: May 2010
Location: Manchester, UK.
Posts: 3,428
Default Re: My Latest Junker. Courier AM Car Radio.

Nick,
Looks like the (far better looking) LW/MW original

Click image for larger version

Name:	Courier-MW-LW-Classic-Car-Radio.jpg
Views:	75
Size:	18.2 KB
ID:	265091

was morphed into this MW only model with that awful logging scale, and the wave change button reassigned as a 208m preset.

Could equally be a 1500m preset I suppose.
__________________
--
Graham.
G3ZVT

Last edited by rambo1152; 22nd Sep 2022 at 1:25 pm.
rambo1152 is online now   Reply With Quote
Old 22nd Sep 2022, 2:21 pm   #27
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,419
Default Re: My Latest Junker. Courier AM Car Radio.

Mods permitting for ID only etc ?:

https://www.ebay.ie/itm/144650943104...YAAOSwK7BinKBg

https://www.service-data.com/product...06/9943/m22306

?

Lawrence.
ms660 is online now   Reply With Quote
Old 22nd Sep 2022, 3:00 pm   #28
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by rambo1152 View Post
Nick,
Looks like the (far better looking) LW/MW original

Attachment 265091

was morphed into this MW only model with that awful logging scale, and the wave change button reassigned as a 208m preset.

Could equally be a 1500m preset I suppose.
It's set to 1500m Radio 4

Anybody know why car radio's use inductor tuning ? presume something to do with ignition noise
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 3:14 pm   #29
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by ms660 View Post
Is there a point to posting the ebay listing ?
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 3:30 pm   #30
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,419
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by Radio Scotland View Post

Is there a point to posting the ebay listing ?
Yes there is because it looks very similar to yours, the service info for it is available in the link I posted, which might help in future if the circuit etc is the same as what's in yours should your receiver develop another fault in the future, I don't have a copy of that service info but it might give alignment/adjustment instructions which would also be a bonus if required.

Lawrence.
ms660 is online now   Reply With Quote
Old 22nd Sep 2022, 3:34 pm   #31
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by ms660 View Post


it looks very similar to yours,
Lawrence.

It is mine
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 3:46 pm   #32
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,419
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by Radio Scotland View Post
It is mine
Which was unbeknown to me at the time because you didn't provide any model number information.....

Lawrence.
ms660 is online now   Reply With Quote
Old 22nd Sep 2022, 4:07 pm   #33
Mr 1936
Hexode
 
Join Date: Mar 2017
Location: Romsey, Hampshire, UK.
Posts: 319
Default Re: My Latest Junker. Courier AM Car Radio.

Hi

Car radios use inductive tuning because:

It is physically smaller

It is electrically more suited to a short rod antenna. In a traditional design the first tuned circuit has a fixed parallel capacitor made up of the capacitance of the antenna, plus a short length of special low capacitance coax, plus the aerial trimmer, plus a fixed value. Since the first two are outside the control of the designer, the trimmer is used to ensure alignment.

Since FM came along this has all gone out of the window, and a FET preamp with no trimmer is used.
Mr 1936 is offline   Reply With Quote
Old 22nd Sep 2022, 4:52 pm   #34
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by Mr 1936 View Post
Hi

Car radios use inductive tuning because:

It is physically smaller

It is electrically more suited to a short rod antenna. In a traditional design the first tuned circuit has a fixed parallel capacitor made up of the capacitance of the antenna, plus a short length of special low capacitance coax, plus the aerial trimmer, plus a fixed value. Since the first two are outside the control of the designer, the trimmer is used to ensure alignment.

Since FM came along this has all gone out of the window, and a FET preamp with no trimmer is used.
Cheers for that, Makes sense ,


Jay
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Old 22nd Sep 2022, 9:09 pm   #35
rambo1152
Dekatron
 
rambo1152's Avatar
 
Join Date: May 2010
Location: Manchester, UK.
Posts: 3,428
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by ms660 View Post
Quote:
Originally Posted by Radio Scotland View Post
It is mine
Which was unbeknown to me at the time because you didn't provide any model number information.....

Lawrence.
I think he means he bought that actual specimen.
__________________
--
Graham.
G3ZVT
rambo1152 is online now   Reply With Quote
Old 23rd Sep 2022, 9:01 am   #36
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,419
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by rambo1152 View Post
Quote:
Originally Posted by ms660 View Post
Quote:
Originally Posted by Radio Scotland View Post
It is mine
Which was unbeknown to me at the time because you didn't provide any model number information.....

Lawrence.
I think he means he bought that actual specimen.
Yes, which was unbeknown to me at the time....as I already stated....

Lawrence.
ms660 is online now   Reply With Quote
Old 23rd Sep 2022, 10:50 am   #37
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,419
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by Radio Scotland View Post
Anybody know why car radio's use inductor tuning ?
Permeability tuning also solves the potential problem of capacitor tuning gang microphony.

There's also less change in selectivity and gain when tuning across the band.

W.J. Polydoroff did some work with permeability tuning back in the early 1930's, there is an article by him in the 1933 edition of the proceedings of the IRE which starts on publication page 690 in the link below for anyone that might be interested:

https://worldradiohistory.com/Archiv...RE-1933-05.pdf

Lawrence.
ms660 is online now   Reply With Quote
Old 23rd Sep 2022, 1:14 pm   #38
Radio Scotland
Heptode
 
Radio Scotland's Avatar
 
Join Date: Jul 2020
Location: Larkhall, South Lanarkshire, Scotland.
Posts: 622
Default Re: My Latest Junker. Courier AM Car Radio.

Quote:
Originally Posted by ms660 View Post
Quote:
Originally Posted by Radio Scotland View Post
Anybody know why car radio's use inductor tuning ?
Permeability tuning also solves the potential problem of capacitor tuning gang microphony.



Lawrence.

Interesting, Never thought of that as obviously a car radio is subject to a lot of vibration
__________________
Help!! I've been electrocuted by a glass thing that glows
Radio Scotland is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 11:51 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.