This connects to the positive (+) side of the charger circuit. Note that on standard diodes, the banded end is the cathode. Epoxy diodes have been known to sometimes blow apart when severely overloaded, so take reasonable precautions when doing this kind of testing.

Do not draw more current or leave it on longer than necessary for testing the 'temp' diodes may heat up pretty quickly without a heat sink. As long as you stay within the current and voltage ratings of the 'temp' diodes, you should be able to determine if the rest of the charger works. This could be done by substituting a pair of generic silicon diodes for the two on the metal plate. If the regulator circuit is fried, it may not be repairable, so it would probably be best to find out if it works before investing in new diodes. But without knowing how the regulator circuit and SCR are tied in, it's not so easy to say if that's due to a bad diode or something else. Your scope trace definitely looks like only one of the diodes is conducting. Like a lot of modern products, they are made to be thrown away when something goes wrong. The problem with things like that is they're not made to be repaired. Tube: AM/FM Zeniths, RCA, TrueTone table tops Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780 Never worked with these button rectifier diodes. I don't have schematics and need to find that and replacement diodes. I think it was one of the diodes arching. I got an expected spark on the clips at the battery, but also saw a flash in the charger. I repaired that.Ī few weeks ago I put the battery leads on the battery backwards. The plastic holder was cracked and causing intermittent contact. I took the diode holder apart to check them. I must have a bad diode or put one or both in backwards when I took it apart. I think this is a circuit (not sure guessing). Two leads from the transformer go to the anode (+) of the diodes. The button diodes are held in a plastic holder so the cathodes (-) of both diodes are against a metal plate. I checked them with a DMM and they seemed OK. There are no diodes but there is a automatic control circuit, a SCR, Circuit Breaker and a meter for charge amps and LED for charge complete. Not sure the battery needs to be connected to check. I'm guessing it should be full wave and this is half wave trace.

This is a battery charger (test gear of sorts), a Schmmacher SS-51A-PE, has two diodes, button types.

Rectifier diode for battery charger