On Thu, 05 Feb 2004 12:11:19 -0500 Brad Parker <brad(a)heeltoe.com> pounded out: [............] If you are going to use the equipment only occasionally, a tantalum cap is an excellent choice. However, with the current reliability of electrolytic caps, the added expense is something that has to be considered. With old equipment, especially those items that have been in storage a long time, an electrolytic will depolarize. When you hit the ON button, the dielectric layer is missing and the conduction can cause a short, or occasionally, a small bang as the cap and its contents scatter around the chassis. Leakage is generally due to badly formed dielectric layers. In a pinch, you can cure a leaky cap by applying voltage of reverse polarity of about 10% of the rating for several seconds and then bringing the cap slowly up to its rated value to reform the dielectric. To safely re-energize a piece of equipment that is long in the tooth and has been sitting around for some time, you have to bring the voltage up relatively slowly to allow the electrolytic caps to re-polarize. Everyone who is collecting should own a good-sized Variac. You power the box up by bringing the voltage from naught to the operational level with the Variac over a period of about a second or so. This should allow the input caps (biggest and most expensive) to re-polarize without taking out the fuze, or worse, the rectifier. Even with switchers, this will also have a ripple effect throughout the system unless the unit has power management. I have some 50 y/o stuff around here that continues to work without repair by taking the above precautions. In your case, I would replace all the bypass caps on the board if you have had a failure in one - although good, they are probably marginal at this point in time. When replacing electrolytics, I typically go for the 105 degree items if they will fit (the current versions are substantially smaller than their predecessors), or for higher voltage beasties with the same temp rating. I also add heat protectors to caps that have been sited next to power resistors or large, silicon embers (monitors are notorious in this regard). Heat will take out an electrolytic faster than anything else. Only if it doesn't happen to me...