Osram Music Magnet 4 - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

regenfreak · 23rd Nov 2018, 1:34 am

The problem is more elusive than I thought. I have insulated the HT wire and other wires under the rod with thin polyethylene sheets to stop them touching the brass rod and the metal chassis. But it does not cure the short.

The fact that the resistance between the HT+ and the earth is sensitive to the angular positions of the wave changer suggests the wave switch is also involved. It consisting of three spring loaded brass balls that move up and down depending if the balls lock into the concave holes of the rod. Look like I have to strip the whole thing down to get access to the switches which i dont have the confidence to do.

Ed_Dinning · 23rd Nov 2018, 8:19 pm

Hi Sing, HT is fed into all the cans and is on the rear terminal strip. Try separating the HT and the SG supplies, gradually working from the terminal strip (which could be leaky) outwards, re connecting each wire in turn.

Ed

regenfreak · 23rd Nov 2018, 10:00 pm

Hi Ed thanks for your useful advice. I will have it another shot.

23rd Nov 2018, 1:34 am	#41
regenfreak Heptode Join Date: Nov 2018 Location: London SW16, UK. Posts: 655	Re: Osram Music Magnet 4 The problem is more elusive than I thought. I have insulated the HT wire and other wires under the rod with thin polyethylene sheets to stop them touching the brass rod and the metal chassis. But it does not cure the short. The fact that the resistance between the HT+ and the earth is sensitive to the angular positions of the wave changer suggests the wave switch is also involved. It consisting of three spring loaded brass balls that move up and down depending if the balls lock into the concave holes of the rod. Look like I have to strip the whole thing down to get access to the switches which i dont have the confidence to do. Attached Thumbnails Last edited by regenfreak; 23rd Nov 2018 at 1:37 am. Reason: typo

23rd Nov 2018, 8:19 pm	#42
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Osram Music Magnet 4 Hi Sing, HT is fed into all the cans and is on the rear terminal strip. Try separating the HT and the SG supplies, gradually working from the terminal strip (which could be leaky) outwards, re connecting each wire in turn. Ed

23rd Nov 2018, 10:00 pm	#43
regenfreak Heptode Join Date: Nov 2018 Location: London SW16, UK. Posts: 655	Re: Osram Music Magnet 4 Hi Ed thanks for your useful advice. I will have it another shot.