Getting to dislike tantalum caps

Hi I begining to dislike these things. I recently got an old 2090 Nicolet DSO ( Digital scope ). When I got it, it had a blown tantilum on the 5V for the I/O section. I fixed this and the blown regulator along with it. I originally got it so that I could display things from my analog computer ( That I'm having fun with ). I powered it up and was just getting the parameters right for a nice Rose Engine display when the display went to a defocused dot. I spent the next few hours trying to figure the best way to disassemble this puzzle box. I know scope have to be compact but it would be nice if there was some thng that said, do this first then this and then this. In any case, I figured that it must be something in the main frame, because the display was completely dead. I found the failing area and measure some supply lines. Sure enough, a -12V was missing from the D/A's. It was run by a local regulator from a +18V line and that was dead too. Some more tracing and disassembling, I followed the short to the input module. I wish I'm know this from the start. The input module is easily removed. I should have followed the first rules of trouble shooting, isolate the parts first and have the minimum connected. Now, I'd disassembled the entire mainframe that I'd have to put back together later. The input module is a pain to take apart. A number of places, they soldered grounding straps. After unsoldering, I traced it down to a cap on the common mother board. I reassembled everything and just had it running for about 10 or 15 minutes and the screen went to a fuzzy dot again. This time, I was smarter. I pulled the input module first. This restored a nice focused dot in the left lower corner. I quickly located the next shorted cap and put the unit back together. It has been running now for several hours. I just hope it doesn't blow another cap but I'm sure it will. As you can see, my love for old tantalum caps is lost it luster. I wish there was some way to get them to fail at one time, but then I'd had to do tricks to find a multiply shorted line ( I can do that but it is a lot of pain ). Dwight _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/