On 30-4-2018 8:41, Ivan Vegvary wrote:
Fixing old car battery charger. Do not want to buy new one because I need the 6 volt capability for my vintage motorcycle.

Need to replace a "button style" (Motorola MR2506) rectifier with a "stud mounted" one (Motorola 1N1190A) The stud mounted on has a higher rating.
Question: Data sheet says button battery cathode marked by "dot". Dot no longer visible on installed parts. Is it safe to assume that the wires from the transformer secondary lead to the Anode and the body of the "button style" (cathode) is pressed into the aluminum plate?
Thank you for your help.

Just put it in, and then load the charger with a 12 volt headlight.
Then check polarity, and flip the rectifier connections if the polarity
is wrong.