For what 😨 I want to thank all those who participated in these discussions, related to motherboards, I'm not going to mention them all one by one, but I'm telling you:
Thank you 1000!
On the MSI MS-6741 VER:1, I just finished working on it, I replaced the damaged electrolytic capacitor, and I added the missing one, respectively a 1000uF 6.3V and a 1500uF 16V, for the replacement I used a Rubycon and a Panasonic, now the VRM area is all Rubycon except the Panasonic, which I put in place of the missing one, but ultimately at least this part should not have future problems, due to poor quality capacitors.

Previously I had written, of an identical motherboard but without integrated video, well it seems that despite having the same name, they are two different models, I don't know if the BIOS is incompatible, already because you have to be very careful to update it, here the chip is welded, so you can only reprogram from floppy, assuming that the Recovery BIOS is working.

The model that has the integrated video card is K8M800, and it is written on a sticker attached in a chip near that of the BIOS, the other card without integrated video, should be a K8T800, in practice two different chipsets for the same motherboard, and I would be quite sure that even the BIOS are different (incompatible!), I just hope that the previous owners did not make an incorrect BIOS update, and that therefore they found an unusable motherboard, this one in particular with K8M800, is perhaps more modern than the other, but this interests me relatively, the important thing for me is that it works, And that you can make a nice S.754 PC, which represents a period of passage between the 462 and the subsequent AM2, I don't forget the 939 but it's from the same period, while the 940 I think is very rare especially in a version with 4 CPUs, here's something like that you could admire it at the time, and for many it was a dream configuration.

Ultimately the card will have to be tested, using everything I used on the ASUS K8U-X, if I have the same problems, I will try something else, if it works well, I will have to try to understand if the K8U-X is repairable, we will see and let's hope well.

Well as I suspected, it's the ASUS K8U-X that doesn't work, it must have some problems, you can speculate towards the RAM, but whatever it is, it could be something else, currently it can't reach the BIOS screen, which it should do if there was no problem.

Why did I come to the conclusion that that ASUS K8U-X doesn't work?

For the simple reason, that I tried a lot of RAM, and I didn't have any change, then it can happen that some RAM in a PC doesn't work, but so many is impossible I would say, and the problem is not the CPU, because it comes from a working PC, and therefore the only way to verify that everything works, is to try it in another motherboard!

Said and done, finished fixing the MSI MS-6741 VER:1, there is a small problem, the hook for the CPU heatsink is missing, it is a type used only on the 754 and maybe other subsequent sockets, with only two screws, decided to disassemble it from the K8U-X, unfortunately the lower part is attached with a double-sided adhesive, it does not seem easy to detach it.

I had almost given up, but for a short test, I do without the hooks, and put the heatsink on the CPU, install a 128 MB DDR 400 RAM and connect PCI post card and video cable and ATX power supply.

I try to start and after a few beeps, there is the image, first the MSI logo and then also the first BIOS screen, usually at this point everything works, I should try to connect an IDE CF adapter with CF and DOS memory card, I will do it in the next few days, because I want to screw the part where the heat sink is hooked, without disassembling the lower one.

That's it for today, and I hope in the future to have the opportunity to recover other interesting motherboards, for the Intel 478 D845xxx board, I have the same problem of the occluded holes, but it is not possible to use the mini tips, because there are too many left, and most protrude and do not allow the centering of the hole, I think I will have to look for another system, to free those holes.

I will return to the MSI MS-6741 with Sempron 2600+, later, because first I have another ASUS 754 to try, the format is the normal ATX (which I prefer), the model is K8V-F, both the audio and the LAN are integrated, in addition it has a FireWire port accessible from the back of the PC in the shield area, and a socket next to the NB to add other FireWire ports, this technology was used for the connection of external camcorders or HD, the utility is relative, but the presence avoids the use of a special PCI card, leaving the place free for more.

Going back to this K8V-F REV. 1.03, it comes from an Olidata PC, and is dated 12/2004, I thought it was more recent, but anyway we are always facing a twenty-year-old technology, so if we want to use this card today, we have to take into account the limits, which are especially the use of single-core CPU, and first-generation DDR RAM.

The presence of expansion slots is abundant, we find an AGP 8X slot for video cards, five PCI that can be used to add a modem or other types of cards, the CNR is not present, even if it was expected, maybe there is in a possible Deluxe version, finally there are two DDR memory slots, and from what I remember, on the 754 there are usually two, while on the 939 we find up to four.

The board looks pretty good, the chipset heatsink is missing, and the hook for the CPU heatsink, on the back there are a couple of deep scratches, but they are on areas with wide tracks, and do not interrupt the track, so I would say that after a dusting, the board can be prepared for the boot test, since the electrolytic capacitors do not have bulges.

News about the ASUS K8V-F REV. 1.03, it seems that it is a particular card produced by ASUS for PC manufacturers, so it was not sold in PC stores (from what I understand), in this case Olidata was supplied by ASUS for their PC lines, and from what I understand, the same card is used in other PCs such as Fujitsu, but this could make any update difficult, because you can get confused with other similar models always K8V, honestly I don't know how the normal K8V and the K8V-F differ, however in case of doubt I would avoid any update Of the BIOS (in particular).

I have concluded the boot test, and the motherboard seems to work, I see the BIOS screens, but at a certain point it crashes, due to a Fatal Error, I tried to enter the BIOS, before you see the last screen, but it does not seem to be possible to enter it.

The CPU I used is the Sempron 3000+, unfortunately it is not recognized, and maybe this is the problem that causes the fatal error, in the end I will have to change the CPU and try again, I don't know if the Sempron came out years after the Athlon 64, and maybe this causes the lack of recognition, that is, there is no CPUs stored in the BIOS, or it could be that the 3000+, is one of the last to be supported, and therefore requires a BIOS subsequent to version 1007 present in the BIOS chip of the motherboard.