This group is so dead I thought I'd share a saga about my old hardware reliable 503+ system. I had some problems with my 503+ system that uses a k6-3+ at 550Mhz. I thought it was the PS since the PS fan was locked up, so swapped in another PS, which in fact was a better quality supply made by Delta. Oddly, it was several days after installing the new PS that the system crashed/locked, I reset it and walked away to the next room over to work at another computer. The printer connected to the 503+ was not accessible over the network, so I walked back into the room where the 503+ system lives, and omg, the smell of something burning permeated the air. I killed power and opened the case and did a sniff test, found the CPU to smell the worst, so I touched the HSF, and it was hotter than a firecracker. Further analysis revealed the Vcore PS circuit had 2 bulging electrolytic caps. OH NO me sez, thinking the CPU has just fried. I cycled power just long enuf to get a BIOS boot screen, and to my amazement, the system tried to run. I quickly power down, and pulled the CPU, and started checking some voltages. Seems the CPU was getting 3.8v, that's right, 3.8v, only 1.6 volts above the max spec for the CPU. I surmise that the bad fan in the old PS may have caused overheating in the box, and closer inspection revealed the Vcore switch mode power supply circuit was having problems. I did a little circuit probing, and replaced the swollen caps, and a voltage test revealed the CPU socket was still getting 3.8v still (had the CPU out of the socket during these tests just in case). The signal from the PWM controller should have the MOSFET turned off, but it was conducting lots of current to the CPU socket. Sure looked like the MOSFET in the Vcore circuit had died (it's drain-source impedance was quite low with no power on the system). I searched the net for info on the device that failed, it is an n-channel enhanced mode MOSFET made by Hitachi. I found the data sheet on the 8-pin Vcore PWM controller chip (it sits right by the MOSFET device), and a typical circuit schematic was provided by the manufacturer in its data sheet detailing how such a CPU PS circuit should be built using a MOSFET device. A brief survey of some old boards I keep around to cabbage parts out of yielded a good quality Philips MOSFET device of similar specs (I have to complement Abit in their AX7 design, I've stolen all the PS caps out of this old socket7 board, and now I'm stealing the CPU PS components and all were good name brand stuff). Philips has a nice web site for obtaining data sheets on their semiconductor components, I tip my hat to their IT department. The worst part was getting the old MOSFET off the circuit board, some trace damage occurred since the tab/body of the MOSFET device is soldered to a large area copper trace on the mobo, and it's darn difficult to get a enuf heat into such areas to reflow the solder and separate the device from the mobo without special tools. Fortunately, enuf of the copper pad remained (after I tore most of the copper off beneath the MOSFET) to build up some solder onto for soldering to the replacement MOSFET body tab, which was not actually designed for surface mount, but bah who cares, a little jerry-rigging, lead bending, and solder built up on the tab of the replacement device and I had it attached in place. With fingers crossed, I hit the power switch (had pulled all boards out of the mobo, and pulled the CPU) and all was right with the world again as I measured 2.1v in the CPU socket (I use 2.1v with my k63+, seems to be what it likes). I then developed a big smile on my face cuz things are back where they should be, then I drop the CPU and the boards back in, hook up all the cables, and the old workhorse is back alive again. I do recall a dead HS fan on an old AMD233 k6 system where I burned HS fin stripes in my finger when I touched the HS, and it appears a k63+ can also take some serious overvoltage and heat abuse without failing. It's so satisfying to fix a problem like this w/o even buying a single component!