Selenium Rectifier 'Replacement' - UK Vintage Radio Repair and Restoration Discussion Forum

M0FYA Andy · 15th Mar 2016, 4:34 pm

On another forum, someone asked for advice on what to replace the selenium rectifiers with in a ground PSU for the T1154/R1155.

One reply was "I once had a problem with an old high voltage PSU.
The leakage current in the selenium rectifiers was too high.
I left the selenium rectifiers in place, but added a high voltage silicon diode in series with each.
The diode takes all the reverse voltage (no more leakage current problem), and the output voltage did not change, as the old rectifiers are still in circuit, and the voltage drop is the same."

What do folks here think of this - is it a good way to try and retain originality without running the risk of the selenium rectifier failing catastrophically and possibly causing further damage?

Andy

paulsherwin · 15th Mar 2016, 4:41 pm

This is bad practice. The selenium rectifier will drop more and more volts as it ages, and there is the risk that it will fail catastrophically emitting noxious gases. You should disconnect it, and replace it with a diode and resistor. You can leave it in place for cosmetic effect of course.

15th Mar 2016, 4:34 pm	#1
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Selenium Rectifier 'Replacement' On another forum, someone asked for advice on what to replace the selenium rectifiers with in a ground PSU for the T1154/R1155. One reply was "I once had a problem with an old high voltage PSU. The leakage current in the selenium rectifiers was too high. I left the selenium rectifiers in place, but added a high voltage silicon diode in series with each. The diode takes all the reverse voltage (no more leakage current problem), and the output voltage did not change, as the old rectifiers are still in circuit, and the voltage drop is the same." What do folks here think of this - is it a good way to try and retain originality without running the risk of the selenium rectifier failing catastrophically and possibly causing further damage? Andy

15th Mar 2016, 4:41 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,967	Re: Selenium Rectifier 'Replacement' This is bad practice. The selenium rectifier will drop more and more volts as it ages, and there is the risk that it will fail catastrophically emitting noxious gases. You should disconnect it, and replace it with a diode and resistor. You can leave it in place for cosmetic effect of course.