From: pallison49@gmail.com   
      
    David Farber wrote:   
   =============   
      
   > This Schumacher 1042A-PE battery charger stopped functioning today. It   
   > seemed to work for a little while but when I noticed the car battery's   
   > voltage wasn't slowly increasing after performing a 2 amp charge for 2   
   > hours, I checked the voltage at the charger's cables and it was 0 volts.   
   > The continuity of the switches and cables were all good. I did find a   
   > power semiconductor which I could not identify, BTW70-200SN. I looked in   
   > an old ECG cross-reference book and the closest match was for a   
   > BTW69-800 which is an SCR in a TO-218 package. The package seems to   
   > match the device I'm looking for. I made some measurements with my   
   > Simpson 464 DVM on the 2k ohm scale. Pins 1 and 3 measure 38 ohms   
   > regardless of test lead polarity. All other combinations of continuity   
   > measure open circuit. In circuit, pins 1 and 2 are soldered together.   
   > Any idea what this component is or how to test it?   
   >   
      
   ** Could be an SCR maybe.............   
      
   With a 1A, current limited,  DC supply of about 12 V, + on the anode - on the   
   cathode, apply a brief pulse of +50mA at +1.5V to the gate with - on the   
   cathode as well.  The 12 volt supply should the be clamped at about +1.2V.   
   You 38 ohm readings are normal.   
      
      
   .....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)