I have a SASI XEBEC 104526 rev 4 that works ok when there is a fan blowing on it but overheats after a while. Is there a common component that fails more often in SASI controllers but not IDE and others of the era?
Short answer: I don't know, but here's how to diagnose heat-failing components: controlled heat and freeze. The trick is in finding the physical location. I simply don't know if there's a common component on XEBEC products which fails. I do know there are heat-related failures on decades-old computers; so I look for such things when I repair them. Obviously one can just replace "hot" components, but they may not be the source of the problem. Long-term, excessive heat is an enemy. Small hand-held IR thermometers are your friend. I bought one at Radio Shack decades ago for $50. Now they are $15; I'm still using my first one. If you freeze-spray a hot component and the board operates again, you've established cause-and-effect. A temperature-related failure mode can be a solder joint. Or a printed-circuit board through-hole which does not contain (enough) solder: the copper plating of the hole cracks over time and separates when hot or flexed. Components can crack too. I isolate heat-failing components, by putting the board in a freezer, then I install the board back in the device, after heating a SELECTED portion of the board with a hair dryer. Heating different parts of the board, and smaller sections, in succession, should isolate the failing location. "Teach a person to fish...." Herb -- Herbert R. Johnson, New Jersey USA http://www.retrotechnology.com OR .net