UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Kolster-Brandes MR10

paulsherwin · 6th Oct 2019, 1:32 pm

It's normal to have to replace the metal rectifier in these. You can use any suitably rated bridge, with either 4 separate diodes or a dedicated bridge. Use a 100-300 ohm resistor in the HT line to limit the switchon surge and reduce the HT voltage. You may want to experiment with the value so that the HT is absolutely spot on, but it's not really necessary.

Ideally you would use fast rectifiers such as UF4007s in the bridge to minimise noise, but bog standard 1N4007s will probably be fine.

6th Oct 2019, 1:32 pm	#82
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,947	Re: Kolster-Brandes MR10 It's normal to have to replace the metal rectifier in these. You can use any suitably rated bridge, with either 4 separate diodes or a dedicated bridge. Use a 100-300 ohm resistor in the HT line to limit the switchon surge and reduce the HT voltage. You may want to experiment with the value so that the HT is absolutely spot on, but it's not really necessary. Ideally you would use fast rectifiers such as UF4007s in the bridge to minimise noise, but bog standard 1N4007s will probably be fine.