Hello, sorry for the english, i'm feeling very lazy ... i'm mod'ing one of the 486DX2 boards. model is PDX 1019-09 / 0675. fortunately, i had downloaded the docs that were scanned, though it would have been better if the resolution was 1.5x or 2x higher, particularly for interpreting the schematics and the layout. but until now it's almost OK. First mod : a 1500uF condo between the unpopulated J18 and S1. I have removed the solder and the distance between the ground pad and the Vcc pad was within correct range. I am really a decoupling freak, particularly for audio systems (and this board will be used as a diital synthesizer board). I also removed solder out of other unpopulated connectors. Currently for the backup battery and the power connector. I still haven't completed the power system but if i can avoid polarity inversion risks, it's better. So i consider soldering a keyed connector or at least wires to the power supply. More complex is the CMOS battery system : i dislike NiCd for many reasons, and i have a good supply (tens) of 0.22F condos. I could also install a Lithium battery but i'm not sure that it is electrically ok : applying 5V to it would damage the cell, i think. Or i could put one of my Lithium-Ion cells that i got from broken cellular phones ( a silicon diode would drop the 5V to near the 4.2V charging tension and would prevent backwards current at the same time) but the size and the complexity are not worth it. The 0.22F will keep the CMOS config during less time, but there is no worry at all about the health of the battery cells. I also solder the keyboard connector, this will prevent other potential plug misplacement problems. HDD and diskette are no worry, except that the diskette needs 12V, while i use a laptop HDD so it takes less current and only needs 5V. Note : i have found Y2K ISA boards in a shop in Paris. The nice thing is that it removes some of the worries with the RTC thing (according to the doc, the clock is managed by the BIOS through an IRQ, "the old way", so the clock is not updated when the board is unpowered). The 8-bit ISA board contains a Dallas chip with integrated Lithium battery, which is cool, but needs a "driver" because it's not replacing the "integrated" RTC, it's located in another address. I don't need this for my current application. But there's more : the PCB contains an altera MAX7064 with a nice JTAG header, so the CPLD could be reprogrammed for other purposes :-))) I have grand plans for this board. When SW developement is finished, i'll remove the VGA sandwich for reducing the power consumption, and eventually will replace the DX2 with an "overdrive"-style CPU. But more importantly i need a high quality sound output so i'll make a custom board for this with a comfy FIFO. Big question : will i be able to add a custom memory chip that will take over the BIOS before it polls the Diskette and the HDD ? Is there a support for the "ROM BASIC" or (as used later) "Network BIOS" ? The documentation doesn't seem to indicate anything like this. I simply want to run a smallish SW stored in FLASH or backuped SRAM, and forget about the rest. Any hint ? YG