Mystery A.M. transformer - UK Vintage Radio Repair and Restoration Discussion Forum

llama · 16th Sep 2019, 9:12 am

This is the transformer in the mystery RF device I recently offered. It has Air Ministry markings that look like 10M/162 or possibly 10A/162. It has about 10.5mm of laminations and the markings on one side are IP and OP with what looks like an unused tapping. On the other side it is marked OS, T2 and IS. I suppose these are all input/output, primary/secondary (apart from the "T2" connection).

Overall size is 5cm lamination length, 3.8cm max winding width and 2.9cm height. Coloured dark brown varnish.

I wonder if, just out of curiosity and a sense of completion, anyone has the appropriate AP that would identify the characteristics of the transformer and/or the equipment it's likely to have come from. Speculation welcomed!
Graham

Keith · 16th Sep 2019, 9:40 am

Without checking, it sounds as if it might be one of the transformers from the A1134 intercom amplifier as used in the Lancaster bomber (like the one shown here about 2/3 down the page):

http://www.tibblestone.com/oldradios...adio/T1154.htm

If so, I'm afraid one or more of the windings is likely to be o/c.

M0FYA Andy · 16th Sep 2019, 10:13 am

More likely 10K/162.
This is shown in AP1086 as a Transformer Type 285, LF Output, overall ratio 1:2

Andy

Jon_G4MDC · 16th Sep 2019, 10:45 am

Would those need a beehive trimmer capacitor and what looks like an inductor with an adjustable core at bottom left?

ms660 · 16th Sep 2019, 10:52 am

The chassis look like an electrickery backing box...

Lawrence.

AC/HL · 16th Sep 2019, 11:17 am

It is: https://www.vintage-radio.net/forum/...d.php?t=159770

ms660 · 16th Sep 2019, 11:33 am

A 10K/162 transformer was used in the R1147 receiver.

Lawrence.

ms660 · 16th Sep 2019, 12:06 pm

As a guess it might be for IFT alignment?

Lawrence.

M0FYA Andy · 16th Sep 2019, 12:06 pm

Quote:

Originally Posted by ms660

A 10K/162 transformer was used in the R1147 receiver.

Well spotted!

Andy

ms660 · 16th Sep 2019, 12:09 pm

Thanks to a Radio Constructor archive.

Lawrence.

Jon_G4MDC · 16th Sep 2019, 12:17 pm

Ah I see, a transformer re-used for a spot of home brew. Sorry I took a while to catch on.

mickm3for · 17th Oct 2019, 5:09 pm

Thanks for device this is the circuit and valve line up pin numbers match resistor at top ht to anode is 56k
any one a clue as to where the green and the green/red wire would go also ideas on what it is

? thanks Mick

G6Tanuki · 17th Oct 2019, 5:28 pm

If the green wire is connected to the red/green wire, the double-triode becomes a "cathode-coupled oscillator" whose frequency is determined by the coil and capacitor.

mickm3for · 19th Oct 2019, 11:36 am

Hi thanks connected green to red green fitted ECC81 6v+200v ht and got a carrier on 1.45 mhz . the other stage i would think is a af osc ? (does not work) caps way off value/oc so transformer is used as a modulation transformer. i would think this is an alignment aid or a marker osc. Will recap and retest Mick

G6Tanuki · 19th Oct 2019, 12:02 pm

Yes the other stage is an audio oscillator - like you said it's set up to tone-modulate the RF-oscillator, so your 'thing' is indeed probably an alignment-aid/test-signal-source for the medium-wave band.

G3VKM_Roger · 19th Oct 2019, 3:49 pm

Quote:

Originally Posted by mickm3for

Hi thanks connected green to red green fitted ECC81 6v+200v ht and got a carrier on 1.45 mhz . the other stage i would think is a af osc ? (does not work) caps way off value/oc so transformer is used as a modulation transformer. i would think this is an alignment aid or a marker osc. Will recap and retest Mick

Or maybe a "pantry" transmitter so you can play recorded music or programmes onto a vintage RX?

73

Roger

16th Sep 2019, 9:12 am	#1
llama Octode Join Date: Jun 2006 Location: St Osyth, Nr Clacton, Essex, UK. Posts: 1,310	Mystery A.M. transformer This is the transformer in the mystery RF device I recently offered. It has Air Ministry markings that look like 10M/162 or possibly 10A/162. It has about 10.5mm of laminations and the markings on one side are IP and OP with what looks like an unused tapping. On the other side it is marked OS, T2 and IS. I suppose these are all input/output, primary/secondary (apart from the "T2" connection). Overall size is 5cm lamination length, 3.8cm max winding width and 2.9cm height. Coloured dark brown varnish. I wonder if, just out of curiosity and a sense of completion, anyone has the appropriate AP that would identify the characteristics of the transformer and/or the equipment it's likely to have come from. Speculation welcomed! Graham Attached Thumbnails __________________ Half my stuff is junk - trouble is, I don't know which half!

16th Sep 2019, 9:40 am	#2
Keith Heptode Join Date: Jan 2003 Location: Tewkesbury, Gloucestershire, UK. Posts: 589	Re: Mystery A.M. transformer Without checking, it sounds as if it might be one of the transformers from the A1134 intercom amplifier as used in the Lancaster bomber (like the one shown here about 2/3 down the page): http://www.tibblestone.com/oldradios...adio/T1154.htm If so, I'm afraid one or more of the windings is likely to be o/c. __________________ Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm

16th Sep 2019, 10:13 am	#3
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,135	Re: Mystery A.M. transformer More likely 10K/162. This is shown in AP1086 as a Transformer Type 285, LF Output, overall ratio 1:2 Andy

16th Sep 2019, 10:45 am	#4
Jon_G4MDC Octode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 1,131	Re: Mystery A.M. transformer Would those need a beehive trimmer capacitor and what looks like an inductor with an adjustable core at bottom left?

16th Sep 2019, 10:52 am	#5
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 10,057	Re: Mystery A.M. transformer The chassis look like an electrickery backing box... Lawrence.

16th Sep 2019, 11:17 am	#6
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,180	Re: Mystery A.M. transformer It is: https://www.vintage-radio.net/forum/...d.php?t=159770 __________________ Bill, BVWS member

16th Sep 2019, 11:33 am	#7
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 10,057	Re: Mystery A.M. transformer A 10K/162 transformer was used in the R1147 receiver. Lawrence.

16th Sep 2019, 12:06 pm	#8
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 10,057	Re: Mystery A.M. transformer As a guess it might be for IFT alignment? Lawrence.

16th Sep 2019, 12:09 pm	#10
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 10,057	Re: Mystery A.M. transformer Thanks to a Radio Constructor archive. Lawrence.

16th Sep 2019, 12:17 pm	#11
Jon_G4MDC Octode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 1,131	Re: Mystery A.M. transformer Ah I see, a transformer re-used for a spot of home brew. Sorry I took a while to catch on.

17th Oct 2019, 5:28 pm	#13
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 9,457	Re: Mystery A.M. transformer If the green wire is connected to the red/green wire, the double-triode becomes a "cathode-coupled oscillator" whose frequency is determined by the coil and capacitor.

19th Oct 2019, 11:36 am	#14
mickm3for Hexode Join Date: May 2015 Location: Chatham, Kent, UK. Posts: 396	Re: Mystery A.M. transformer Hi thanks connected green to red green fitted ECC81 6v+200v ht and got a carrier on 1.45 mhz . the other stage i would think is a af osc ? (does not work) caps way off value/oc so transformer is used as a modulation transformer. i would think this is an alignment aid or a marker osc. Will recap and retest Mick

19th Oct 2019, 12:02 pm	#15
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 9,457	Re: Mystery A.M. transformer Yes the other stage is an audio oscillator - like you said it's set up to tone-modulate the RF-oscillator, so your 'thing' is indeed probably an alignment-aid/test-signal-source for the medium-wave band.