N Cook wrote:
In a valve Dansette Bermuda of early 60s
Been in a loft for years.
The mains wiring is perished and other wiring looks dodgy so testing some
things cold first.
Using 9V battery and 300 ohm dropper shows near enough 9V over the
rectifier, how high V do you have to go with a good one to check it ?
Are there safety grounds anyway for changing to a 1N4007 or so ?
Single element rectifier
Siemens lazy S logo
Made in Germany
2250c50
Kc 0.6e 11/16


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Nigel,

Take another look at the number. Might it be "B250C50"? Many European
rectifiers used to give you the voltage (B, in this case 250 volts) and
current rating (C, in this case 50mA) of the device.

I agree with the other posters that you can replace the selenium with a
silicon diode, but may need to ad a dropping resistor as the B+ may be
higher because of less loss in the rectifier. I usually bring the item
up slowly on a variac and make sure that I don't exceed the voltage
of the filter caps. Better still if you have a factory diagram telling
you what the B+ is supposed to be. Then you can choose an appropriate
resistor, and you might need quite a few watts worth too.

Unfortunately, I can't suggest how you might test the selenium.

Regards,
Tim Schwartz
Bristol Electronics