Steve, First remove the regulator which you suspect anyway. If that does not remove the short, then start removing one component at a time until you find it. A good de-soldering tool makes the task a lot easier, and if the price of the potential parts replacement is high, perhaps it is time to invest in a de-soldering tool - you won't be sorry, and you can remove parts non-destructively in most cases.
If you do not have a de-soldering tool, the easiest is to cut traces - start by cutting a trace so it divides the suspect components into 2 equal groups, find out which half the short remains in and divide that section into 2 groups again - you don't have to make as many cuts, and you will find it more quickly. I don't know of an easier method unless you happen to spot a solder bridge along the way. 73, Don W3FPR > -----Original Message----- . When > I remove U1 on the kpa100 board I get a dead short at pin 1 of U1. This > could mean that the 5 V regulator is bad but there are other components > connected to this line and any one of these components could be defective > (U3, U4, C23, C89, U6, etc). > > I am now faced with developing a procedure to isolate the bad > part. I have > already inspected the board for shorts and do not see any. The fact that > the kpa100 worked before leads me to believe that a component may have > shorted itself out. > > I could destructively remove each component until the short > disappeared but > then I would need to replace possibly a lot of parts. The other option > would be to isolate each part one at a time by cutting traces. Once the > part was deemed OK, I would have to patch the trace and go on to the next > part. I would end up with a lot of patched traces. > > Any suggestions? > > Thanks, > Steve, W2MY > > -- > No virus found in this outgoing message. > Checked by AVG Anti-Virus. > Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005 > > > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005 > -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005 _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
