For today it is scheduled, a test with the Chicony iDX4-100 PC, I found a 4 cm fan 🌬, which I will connect directly to the molex of the drives, unfortunately in this type of motherboards, there is no socket for the 3 PIN FAN connector, or 2 PIN, these appeared if I'm not mistaken on the S.7, in short, a few years after the 93-94, of course anyway at a certain point, the higher CPU speed, made the PCs louder because the fan was essential for operation without any problem, but initially the systems for hooking the Heat sink, they were not the best, some could easily disengage, because in fact there were four clips, and they had to be hooked directly to the CPU, many then did not use the thermal paste.

For the test I will use a game like Duke3D, currently I have loaded the drivers of the SB Vibra16XV, in DOS everything is fine maybe I should just turn up the volume a little, but I can no longer access Windows 3.1, I will have to try to understand if there is a problem, sometimes I remember that you had to do several tests to be able to make the audio work on Windows 3.1, from this point of view the subsequent Windows work better, and indeed for this kind of sound cards, the drivers are already included, and you don't have to load any floppy.

Among the DOS driver files that I installed, there should be a configuration and test program, which could be very useful, first I should see the current configuration, and this could be useful, in case there is a conflict with something else, in that case it would explain why Windows no longer works.

I'll try the same audio drivers on the PCCHIPS M912, although I don't remember if the audio already works, and therefore in that case it wouldn't be necessary to load them, because initially I didn't connect the speaker jack, but once I'm done with the file transfers, I'm trying to make all the installed HW work better, unfortunately for some things, since it's a dated HW, in case of operating problems, you have to try another one that is definitely working, and if the result is a problem with the card (audio, video, etc...), getting the spare parts today, it would be very expensive, some cards like the video ones, can Be very difficult to find for sale.

Here we are again, this morning I connected the fan on the DX4-100 (MB Chicony), I put a thin layer of silver thermal paste, and I started the PC, so far nothing strange, then I started a short Game session with Duke3D, initially I let it run in demo mode, then I started playing a couple of levels, in short I wanted the CPU to heat up a little, and for the moment I haven't seen any locking, everything has always been smooth as oil (!?).

Yes, because in case of problems, you need to understand what causes them, it's not that maybe, solved the thermal problem of heat disposal (CPU), other problems occur due to something else, however usually if we solve the problem that causes the PC to crash, this will work well again.

So now I can say that in the mid-90s, some problems that manifested themselves were not due to a HW defect, but to poor ventilation, or to the assembly of the heat sink without thermal paste, there were even those who put labels 🏷 on the CPUs, I've seen this done even on P4s, however today it is quite easy to remedy it, if we don't find heat sinks suitable for 486 CPUs, you can adapt those of the Chipsets, which are slightly smaller, even if much higher and more efficient, and maybe it may not be necessary to connect a fan.

Currently, the Chicony PC has two SIMM 72 PIN of 8 MB each, in total there are 16 MB, at this point I am considering whether to add another 16 MB, to have a total of 32 MB (8 MB X 4), in this way I can say that the PC would be expanded enough, not at most but not so far, the maximum would be CPU S.3 133 MHz and 64-128 MB RAM, but I don't know I prefer to use the S.3 133 MHz on a 486 PCI, which together with a VGA PCI, and a lot of RAM, could be more suitable for Windows 98SE.

But that will be the idea, which is possible to realize, only after running the only 486 PCI motherboard I have, initially I will start with an AMD 486DX4-100 CPU, it would be slightly slower than the iDX4-100, because it has a cache of 16 KB (instead of the usual 8 KB).

Later I have the possibility to upgrade, but a lot depends on how the PCI works, some go at the same frequency as the FSB, others instead go to half frequency, so it can happen that at FSB 40 MHz, the PCI goes to 40 or only 20 MHz, the first a little high for some video cards, the second too low, and could slow down the PC a lot.

Still on the subject of 486, I performed some tests on the Chicony with iDX4-100 (it's no longer called 486), I tried Windows 3.1, well it works but without audio, so I think it's necessary to load the drivers directly from Windows, it's a job that was done via floppy, but in Windows there are already some audio drivers, like Sound Blaster or other similar tabs, so I have the doubt that it's enough to select one of those, rather than using a floppy with the drivers.

The ISA Audio card is SB 16 Vibra, I think it is the last version produced for ISA, if I'm not mistaken later we switched to SB 16 PCI, here clearly you are obliged to use ISA cards, because the MB is ISA-VLB, I point out that in DOS the audio works, so unless there are strange problems, it should also work in Windows 3.1.

I haven't closed the PC yet, because I upgraded to the RAM, I had two RAMs of 8 MB each (16 MB total), I added two more of 8 MB, now in total I have 32 MB, I already know that someone might think, that now you could also update Windows, moving from 3.1 to 95, but for the moment I would like to keep Windows 3.1, the disk is just over 500 MB, I wouldn't want to fill it, I prefer to keep a lot of free space, of course if I wanted I could use the program that doubles the disk capacity, in the past I used it, But in reality it depends a lot on the files, some can be compressed a lot, but if most of the files are compressed only a little, the doubling of capacity is not actually achieved.

So for the moment I would say that, this PC solved the problem of audio drivers, can be considered as a definitive PC, that is, there is no need to add anything else, but maybe at the time it had an ISA LAN (10M), here is this could add, but overall it has an abundant amount of RAM, which a part can be used as a RAM drive, and could speed up the execution of DOS programs, since the hard drive is quite dated, and even if maybe at that time it could be relatively fast, so using the RAM DISK, the slowdown due to reading and writing is eliminated .

I closed the Chicony PC with iDX4-100, for now I don't have to do anything else inside, I just have to activate the sound from Windows 3.1, and this is done without having to open the PC.

I go back for a moment to the PCCHIPS M912, I saw on the MB that the version is 1.7, here if you wanted we would have to remove the fake cache, the fake chips should be removed one by one, once all the holes are free you can proceed to solder the sockets, while waiting to get working L2 cache chips, but I also imagine the TAG 🏷 chip, which I imagine is also the fake one.

In this PC I have 20 MB of RAM and a 5V IT'S 486DX2-66, I have to check if there is the possibility of using CPUs with lower voltages (from 3V to 4V), in that case I could switch to FSB 40, to change CPU with DX2-80 or a DX4-120, currently it is a little slowed down, the L2 cache of 256 KB that you read on the second boot screen, is a bluff of the BIOS, it makes you believe that there is but it is not so.

Another upgrade I will do is to change a 72 PIN RAM, in total it is 20 MB, and it should be a 4 MB and the other 16 MB, I was thinking of changing the 4 MB one with a 16 MB, to get a total of 32 MB, in this motherboard there are four sockets for SIMM 30 PIN, but for me it is useless to put them when there are more 72 PIN sockets, maybe they could try, but given the rarity of the 4 MB modules (or more), I really don't think I'll use them here, assuming I have them.

I change the motherboard, I try the MB PINE PT-2068.1 with i486SX-25@33, I change the CPU with the 486DX2-66 (blue heat sink), unfortunately despite some attempts it does not work, returning to the SX25 instead it works.

I try a second DX2-66 (this time AMD), sometimes it gives some starting signs, shows a couple of codes, but nothing on the video, so I think the problem is the socket, I have to make a few more attempts with other 5V CPUs, all 486DX2-66, I hope at least one can work, I wouldn't be thrilled if the only one that works is the 486SX.

There is another 486DX2-66 waiting for a check, it is a ZIDA 4DVP with 128 KB L2 cache not working, years ago it worked and I had expanded it to 256 KB, then it didn't work anymore, I don't know if those L2 cache chips work, I don't have a tool for verification, but I think I've tried others that are definitely working, and I had the same problem, so we'll have to understand if there's a fault nearby.

To recover a DX2-66, I would have to replace the one on the PCCHIPS M912, of course I would have to switch to something faster, that is a DX2-80 or possibly a DX4 100-120, being a VLB motherboard, they can be used with FSB 40, with a maximum of two VLB cards, in this case having a VGA and a Controller, I would be fine, it is also true that there are combo video cards (with controller), but I think they are intended for those PCs like the 486DX50, after all the common use of VLB cards was video and controller, other types of VLB cards are quite rare and personally not I've seen some, although it's likely that there's someone who has one or more in their collection.

Here I noticed that in some situations, that is, in some resolutions, you see black vertical lines, sometimes even quite big, I think it may be a video card problem, or maybe the contacts need to be cleaned, I don't think it's a driver problem, since I use DOS, rather it could be a problem with some video RAM chip, but you have to make a try with a similar video card, if the other one is good, then you could start doing some tests on the problematic card.

On the PINE PT-2068.1 with SX25@33, I transferred other bench DOS programs, initially I had connected the Chicony iDX4-100 PC, but shortly after starting the transfer, an error occurred in the file transfer, I did some tests, but there must be something wrong, maybe one or both of the RAMs I added, it could have something wrong, I will try with the QTPRO diagnostic, first with the four RAMs and then removing the two to get to 32 MB, in case everything goes back ok, I should try two more RAMs, hoping they are fine.

I'll see if tomorrow I can do some tests with the ZIDA 4DVP, in that PC years ago the L2 cache failed, and if I'm not mistaken there is a problem with one or two VLB slots, one definitely works, because there is the 1 MB VLB CL GD5424 video card, the doubt is whether I used an ISA controller, or a VLB (?), years ago I didn't have other VLB controllers, so I used the ISA, but later I bought batches of cards, with a couple of VLB controllers, I even have a couple that are malfunctioning, in the future I could be Forced to repair them, given the current prices.

I hope I don't get bored with all these 486, I know lately I left out the PCs I had worked on, but soon I could change Socket, returning to something later, I'm slowly reorganizing the old PCs, to try to differentiate them a little, I don't want PCs all of the same type, so from the four 486DX2-66 VLB, at least a couple will be updated, in fact only one is missing, the other upgrade was made days ago, with the change of Intel CPU, from 486DX2-66 to DX4-100.

Regarding the PCCHIPS M912 V.1.7 motherboard, I checked if beyond the fake L2 cache chips, there was the TAG chip, this turned out to be fake (him too!) So an additional chip will be needed, for the cache instead at least four are needed, but there is room for another four, if we find eight (8+1) chips of the capacity and type (same), we could proceed with the removal of the fake ones, and the welding of the sockets, for the latter in the motherboard the use of DIP32 or DIP28 chips is provided, so the sockets could be welded to 32 PIN, in which eventually we can install the DIP28 chips.

For the BIOS, I'm sure it needs to be updated, because it shows an L2 cache that isn't there, and if I'm not mistaken, it's not possible to make any changes from the BIOS, such as access times or anything else, the BIOS chip is not soldered, this is already very positive, I think that if it was of the rewritable type, you could only make an update from floppy, because it's a DIP28, they change the size compared to the L2 cache chips, I don't think you can reprogram with a programmer for DIP32, on this thing clearly I wouldn't know if it's possible or not, however it wouldn't be from Exclude.

An advantage of the update would be the support for the fastest CPUs of AMD and Cyrix, we are talking about 5X86 with speeds of over 100 MHz, but for these it is necessary that the motherboard is able to provide the CPU with less than 4V, and looking at the motherboard, you see a small black heatsink, which covers the voltage regulator, if this is not fake too, you can easily install any 486 you have, just paying attention to the jumpers, because an incorrect setting can cause the CPU to not start, so be very careful, and above all check before Install the CPU, that the voltage is correct, here it is obvious if the CPU is always 5V, the arrangement of the voltage jumpers should not be changed, and you can do without checking.

The advantage of the real L2 cache, will it be obvious or not? I think it depends a lot on the type of use we will make of the PC, in general, however, I prefer to have a real and working L2 cache, because the difference is greater between 0 and 128 KB, rather than between 128 and 256 KB or 256 and 512 KB, that is, not having one is definitely worse than having a few but good, while having a little or twice as much would only make a marginal increase, of course no one prevents you from installing the amount you want, according to the manual you can even reach 1! MB of L2 cache, but on a 486 having 128 or 256 KB was normal.

I start with the PINE PT-2068.1, I tried some 486DX CPUs, but none of them worked, the PC never started the post code sequence, with a couple of CPUs after several attempts, it had displayed some code, but then it stopped almost immediately, I don't know why it happens, maybe it's the socket that has some not perfect pin contact, but I don't think it's possible to upgrade at this point, in fact I should put it back to 25 MHz.

Among the benches I ran Phil's, for the verification of the cache, he got scores that I can't say if they are adequate or not, but since there is no L2 cache, I don't think there is much to evaluate.

Just because I needed a 486DX33, I took out a second PINE PT-429 motherboard, this one is in baby AT format, and has the VLB, unfortunately there is no Voltage regulator, but there is a 128 KB L2 cache, the chips are real and also the TAG 🏷 one, I will try to put a CPU of at least 66 MHz, among those I have available.

I noticed that it has a reserved space, the Cyrix Coprocessor, which must be welded under the CPU, should be destined for the Cyrix 486S, which had compared to the i486SX, 2 KB L1 cache and the possibility of adding the Coprocessor, although I have seen in the past, intermediate sockets in which it had to be welded.

If I can I would like to do some bench, I also found an HD connected, there should be DOS and Windows 3. X, it's been several years since I last tried it, and I think there's a problem with the keyboard, which had operating problems, that is, no key worked, and it was not possible to access the BIOS, and store the changes.

Well for the moment I continue with the 486, I took them out to review some things, one for example is the CPU, in some PCs despite having a DX2-66 5V installed, it is possible to change and use CPU from 4V or less (up to 3V), in others instead it is not possible to use these CPUs, except using an interposer (which I don't have).

As I wrote, I have a ZIDA 4DVP with a Cyrix 486DX2-66, in the past I had an AMD 486DX2-66, but I removed it, because it had failed and the CPU had ended up on another PC (the Chicony!), later I found this Cyrix with a heatsink included, this allows you to do without a specific heatsink for 486, there is no fan but I think you don't need it.

Looking at the frequency generator, Chronotel brand and the silkscreens, I was sure that there were not only three FSBs available, and that beyond 25 33 and 50 MHz, there was at least 40 MHz, the MB manual was found to be more detailed, as you can see, there are both 40 MHz and 20 MHz, maybe there are also other frequencies (secret), like 16 MHz or something above 50 MHz (?).

Also from the manual, you can see that the motherboard is one of the first VLBs for 486, on a page at the end, there is an update on the new CPUs available, including the DX2-66.

But the important thing would be to fix the L2 cache, then at that point you can start thinking about some upgrades, the most interesting one would be to change RAM, both to increase the capacity, but also to decrease the access time, from the current 70 ns to at least 60 ns.

Maybe a lower access time is not necessary, if we stayed with the 33 MHz of FSB, but if I wanted to bring it to 40 MHz, installing a DX2-80 here maybe, faster RAM could be useful, if we select 0WS, which allows a slight increase in bench scores, but at this point it is likely that even the L2 cache chips, will have to be re-evaluated, and if necessary replaced with others faster than those currently present.

The last batch of motherboards of 2025, is this one with three MB, two ASUS and one Intel, the Sockets are 754 - AM2 - 478.

I had no interest in getting other motherboards to repair, but this batch was cheap, and the boards are also equipped with CPUs, on the 754 you can read Sempron 3000, the other two have the heatsink on and you can't read anything, in that AM2 the shield is included, let's see them one by one.

I start from the S.754, ASUS K8U-X with some electrolytic capacitors swollen in the VRM area, apart from this it seems in normal condition, after the replacement of the electrolytic capacitors, it is very likely that it can work again, the chipset is ULI, if I'm not mistaken it is ALi chipset, which later I don't know why, they started calling ULI, for the rest it seems to me well integrated, with audio and LAN on board.

The other ASUS AM2 is an M2V - TVM/V, it seems in even better condition, the chipset is VIA maybe it is not the best, but being an AMD card, it is quite common to find such a chipset. This card, unlike the other two, has PCI-E slots, for the video card there is the 16X, but for other cards there is a 1X, complete the slot equipment, two normal PCI slots, very useful for using old cards, even if the uATX format limits the number of slots, here we have enough, considering that there are integrated Audio and LAN.

Finally the Intel motherboard, a D845GEBV2 S.478, a classic Intel board that does not offer much choice in the BIOS, are usually quite limited in options, but on the other hand it should be very reliable and with fairly normal performance. Given the use of DDR slots for RAM, it should be suitable for P4-NW CPUs, probably 400 and 533 MHz FSB, I'll look at the manual but I think it doesn't support 800 MHz ones, although I wouldn't mind at all, but for the presence of only two RAM banks, I don't think the FSB 800 is supported.