On Tue, 16 Feb 2010 16:07:06 -0500, Craig Roberts wrote: >What condition(s) would take out the 5A fuse?
You don't mention if the fuse blows with no power supply board plugged in. A short anywhere on the 13.4 volt rail will take the fuse out instantly. I had this happen due to a miswired pilot lamp socket in an RV-7. Normally, the outer shell of the pilot lamp socket is connected to ground; in this unit it was connected to +13.4, and accidentally shorted to the chassis as I was adjusting the position of the pilot lamp for best lighting. It is also possible for the lamp socket lugs to short to each other, or to the chassis, if the sockets or wires have been moved. Or you could have a shorted lamp, but that would be extremely rare. Of course, there could be 100 other possible causes, but the lamp sockets are probably the easiest to check. Perhaps one of the Molex pins "shifted" just enough to short to something on the underside of the chassis, or an electrolytic capacitor on one of the supply rails let go. For future reference, it might be a good idea to set the trimpot to midrange before you power up, or measure the old trimmer with an ohmmeter before removal and set the new one to about the same value after installation 73 -Jim . 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim(dot)exofire(dot)net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
