[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] Pig SISG: Destroying the Indestructible

Further damage report:
    Today I swapped out the bad SISG4 board with the  one I had ben keeping 
for a small Twin project. All components were the same, so  I just took out the 
two terminal screws, broke loose the mounting silicone, and  dropped the new 
one in place. Easy!
    When I examined the bad board from all sides, I  realized another SIDAC 
had bit the dust - the one on the "bottom" of the stack  of three in that 
section. It didn't look that bad until I poked it, and realized  its tab was loose 
as well. I shoulda figured one of the other SIDACs was  dead  - the heat from 
the blasted-open middle SIDAC blistered the solder on  the tabs of the two on 
either side.
    Although the IGBT looked fine, I put a ohmmeter  across the section and 
read a dead short. So I took the IGBT out, and sure  enough the 
collector-emitter resistance is very zero (with a DMM, leads in  either direction). 
Interestingly enough, the resistance from C-G and E-G is 10  ohms, again leads either 
direction. And yet there's no visible external  indication that there's 
anything wrong with it. Anybody wanna buy a used IGBT,  as-is? ;)
    So far, the total is two SIDACs, the 24V  TVS, and the IGBT all dead in 
that section. And the coil still worked fine! 
-Phil LaBudde
Center for the Advanced Study of Ballistic  Improbabilities

**************Create a Home Theater Like the Pros. Watch the video on AOL 
Tesla mailing list