Sumida inductors if transformers - UK Vintage Radio Repair and Restoration Discussion Forum

dboleham · 14th Dec 2022, 6:22 pm

Please can anyone help me? I'm wondering what is the difference between white, yellow and red inductors in the follwing SUMIDA range - Type: P-10R/FM, P-10R/AM, P-10R/SW, P-10R/MW, P-10R/LW. I can't find anything about this on the web although I have found details of all of the above inductors but it's not clear which 'colour' they refer to. Any help would be much appreciated. Thank You Dave

Jolly 7 · 14th Dec 2022, 10:22 pm

Good evening and welcome to the forum.

Are you trying to build a superhet transistor radio or repair one ?

Typically, but not always, the first coil in a MW superhet radio is red, which is the oscillator, the first IF yellow, the second IF white and the third black or green. It is important to stick to a set of coils from the same manufacturer, as the inductances and properties can vary even with the same colour coding.

There are Chinese HX 108-2 superhet kits which come with all the coils and used to be quite cheap. These might be a source if you are looking to build a kit. Using one of the kit coils for repairing another set can be hit and miss for reasons I have stated above.

Hope this helps a little. I've attached a picture of a Sumida oscillator coil I found on the internet. The IF for this one is 455 kHz.

14th Dec 2022, 6:22 pm	#1
dboleham Diode Join Date: Dec 2022 Location: Camberley, Surrey, UK. Posts: 1	Sumida inductors if transformers Please can anyone help me? I'm wondering what is the difference between white, yellow and red inductors in the follwing SUMIDA range - Type: P-10R/FM, P-10R/AM, P-10R/SW, P-10R/MW, P-10R/LW. I can't find anything about this on the web although I have found details of all of the above inductors but it's not clear which 'colour' they refer to. Any help would be much appreciated. Thank You Dave

14th Dec 2022, 10:22 pm	#2
Jolly 7 Octode Join Date: Feb 2018 Location: Southampton, Hampshire, UK. Posts: 1,061	Re: Sumida inductors if transformers Good evening and welcome to the forum. Are you trying to build a superhet transistor radio or repair one ? Typically, but not always, the first coil in a MW superhet radio is red, which is the oscillator, the first IF yellow, the second IF white and the third black or green. It is important to stick to a set of coils from the same manufacturer, as the inductances and properties can vary even with the same colour coding. There are Chinese HX 108-2 superhet kits which come with all the coils and used to be quite cheap. These might be a source if you are looking to build a kit. Using one of the kit coils for repairing another set can be hit and miss for reasons I have stated above. Hope this helps a little. I've attached a picture of a Sumida oscillator coil I found on the internet. The IF for this one is 455 kHz. Attached Thumbnails Last edited by Jolly 7; 14th Dec 2022 at 10:23 pm. Reason: Typos