Hi-Thanks for having me on. Hoping someone could answer a question on a 6/2 ampcar battery charger that I'm trying to bring back to life.There are three wires from the secondary side of the transformer the two outside (red)wires go to diodes (one for each wire)that are attched to a common bar(heat sink)which is attched to the positive battery clip. The other wire (black) goes to the negative battery clip. My question is, should the two diodes be attached with their cathodes to the bar? Thanks

What you have is a center tap full wave rectifier. The cathode is the positive and should be connected to the bar.

I thought that was right but was alittle confused since there are two wires going to the bar each with a diode.Transformer is also burnt up so can't check voltage on the wires.Thanks for the help.

If the transformer is burnt -- it's dead.

Stop.

Buy another device.

If the TX is burnt up, is one of your diodes shorted? The TX is the most expensive part but MPJA.com is in Fl. and has some reasonably priced ones. I just tore into an annunciator power supply that was clearing 7A slo-blos on Friday. It was just a full wave center tap, unfiltered supply as you described but with 1N2129A 100V, 60A stud mount rectifiers. One was shorted. The supply seems like overkill for the size of the annunciator.
Joe

I would not spend a lot of money trying to fix a primitive
battery charger. You can usually find a fairly nice one in a garage sale for a few bucks. The transformer will usually be the most expensive part in one.

I replaced the stud mount diodes with bigger 25amp ones that wasn't too exspensive.I know the smart thing to do would be to trash the charger and buy a new one but at the moment I'm semi retired(can't find work ha-ha)and thought I'd try fixing this.If I can find suitable transformer reasonable I'll be ok with that.I'll try the MPJA site.Thanks.