Advice/Suggestions for repairing Apple III power supply

---snip--- Hi It isn't totally true that you have to remove the caps to locate the failed one or even ones. The caps typically go completely short one at a time or have enough difference in resistance that the method I posted in the previous post will locate the dead short. I've used this method with as many as three shorted caps. If all are true hard shorts, it is a little more difficult but methods of moving where you connect the supply will help to isolate multiple shorts. It is true though that to locate failing electrolytics that are in the process of drying up but still not shorted require removing to use an ESR meter. Tantalums do tend to fail short and use a dry electrolyte. Ceramics also tend to fail short as well but this is rarer than tantalum failures. Old electrolytics are often just open for low voltage applictions. I have a number of older Lamda bench supplies. I find it interesting that the only electrolytics to be bad in these are a number of axial lead ones with the lable stating " Long Life, Made by Lambda". I suspect they really should have stuck with powersupplies and leave capacitor making to someone else. As was also mentioned by others, one should not run switchers without a minimal load on the major output. This is usually the +5V. This is because, even though when you measure the voltage, it looked good, when the power first comes on, these can significantly over shoot and blow components in the regulation path. Always supply some load. If the supply has multiple switcher paths, it is necessary to load those outputs as well. It is typical for most consumer supplies to use the switcher regulation only on the +5v and then use linears on the +- rails of 12V. Dwight _________________________________________________________________ http://newlivehotmail.com