I have some 486 waiting to be repaired, one was bought 30 years ago, it only worked for a couple of days, and went to service a couple of times, without them having to solve the problem (freeza shortly after starting up), I kept it, and several years ago, I tried to turn it back on.

Honestly, I don't know if the motherboard returned from the assistance is the same one I had sent, that is, if they changed my motherboard with another (?).

Doing the boot tests, I tried the CPU in another PC, and it was broken, putting the one working, I saw the first BIOS screen on video, and then it crashed, every subsequent attempt showed nothing more.

I update the current configuration, instead of the Cyrix DX2-80 (5V) mounted on an intermediate socket, I tried other CPUs, with an AMD DX2-66 I saw the BIOS screen on the video, then an Intel DX-33 and finally an SX-25.

The RAMs are 30 PIN, four of 1 MB each (NEC 2+1 chip), but in this card it is also possible to use a 72 PIN RAM, or both types.

On the paper manual, there are various combinations, in the 30 PIN ones, there are some strange 512 KB and 2 MB modules, but it could be a translation error (at least I think), and all the jumpers are set correctly.

The motherboard is still almost like new, there is only a slight dust, observing it I notice a trace in the battery area, oxidized green, I will have to investigate to understand where it goes, I see that it passes under the BIOS chip, maybe that could be the problem (?).

Unfortunately it will have to be scratched, to make the COPPER underneath appear, fortunately the warranty has expired, since 01/1996!

If I find an interruption, the problem of not starting could be solved, for the original problem, I don't think it was caused by the Cyrix CPU, which maybe started to fail, because with the AMD it happened again ️

After performing some checks, I can rule out that the problem comes from the UMC chipset, by the way the motherboard is a Power Tech MB457, AT Industrial format, usually these boards are sold with U5 CPUs, here maybe in Europe you couldn't sell such CPUs, but there was still the socket (1 or 2?), in which to insert the 486 at 5V, unfortunately it does not have linear controllers, to use 486 CPU at lower voltage, if you wanted to use you needed an interposer with regulators on board.

As anticipated, originally the CPU was a 5V Cyrix Cx486 DX2-80, but it was mounted on an intermediate socket, which in the back has some pins connected to each other, I see three very thin wires of different colors, which bridge two socket pins, from what I know, they serve the Cyrix CPU for the cache, but when the PC worked, the intermediate socket had been removed.

On the fact that the CPU does not work, there would be the same doubt as before, that is, if the motherboard sent for service, has been changed with another, in that case the CPU could also have been changed (?).

The card was bought new, and when it worked it was very fast, compared to other 486 DX2-66, although this card does not have the L2 cache, it is also true that at that time, the fake cache was very widespread, so having it or not was the same, that is, if they were not real cache chips, the performance was comparable.

Maybe, however, the FSB at 40 MHz instead of 33, could make the cards work faster, as VGA ISA I had a 1 MB Trident 8900, all in all not bad for DOS use, with Windows 3.1 only at high resolution you could see a bit of slowness, but I think it was quite normal at that time.

Also on the 486 PC that I have in repair, I have an ATC-1411B format AT Industrial , the card has a welded CPU of the UMC, a U5SX 486-33F, there is also the possibility of welding a socket 2 or 3, but the holes should be released closed by the pond, also there are 4+1 empty sockets, which are used for the cache and the TAG chip 🏷, maybe the chips were removed by the old owner, honestly I don't know if that TAG 🏷, is essential for the operation (?), however apart from the oxide damage, and a couple of missing SMDs, there would be to be replaced The 72 PIN RAM bank, a hook is broken.

In recent days, I have scratched the green to expose the copper, then I should check which tracks are interrupted, and finally I would have to clean inside the ISA slots, some of the PINs are oxidized, it would be the case to see if it can be removed.

There is some work to be done in the back as well, in particular a scratch, it should be checked, to see how many tracks it has interrupted.

An interesting thing, next to the BIOS chip, there is the possibility of adding a regulator and various SMD, to power the CPU at voltages of about 3V, this would be useful in case there is the Socket, but honestly I would never remove the welded UMC CPU, both because it is I imagine rarer, compared to the normal ones (from Socket), and because it should be a better CPU than Intel equivalents or similar.

Regarding the BIOS, the chip is a DIP28, out of curiosity I saw what chip it has, an ST M27C512, interesting also because there is a round window (transparent), it is used to delete the content, maybe it must be deleted first and then it can be reprogrammed, while the subsequent chips could be rewritten without first deleting them.

The BIOS should be an AWARD, I don't know what version, if I manage to fix it, I should understand it from the BIOS screen on video, however even if I wanted to, I can't remove the chip and read it in the programmer, for that format (DIP28) I don't have an adapter or a support, so the only way maybe would be by floppy, but also not, because you should remove it hot, delete it and then rewrite.

Regarding the motherboards being repaired, I examined a Siemens D1115, uATX format with i440ZX chipset, there is no integrated audio and video, strangely in these reduced formats there is at least one of the two.

As a video card you can use an AGP VGA, but I think the version should be 2X, so not all AGP VGAs can be used, especially the newer ones, but alternatively you can put a PCI VGA, in case you don't have a suitable AGP available.

I'll make a brief summary, the motherboard won't start, giving power to the ATX power supply, an orange LED lights up, and pressing the Power ON switch, nothing happens!!!

This makes me think that there is something interrupted, but looking I don't see anything scratched or burned, but I notice a 14.3X quartz, which is raised on one side, maybe it's broken, I decide to change it, I don't have new spare parts, I recover one from a scrap motherboard, the acronym is slightly different, but I decide to use that one, hoping to solve it this way.

Once replaced, I put the card on the bench, and add everything necessary for a start-up test, including the ISA-PCI post card.

I'll try to start, hoping it starts, unfortunately nothing happens!!!

There should be another fault, maybe in the start circuit, honestly I don't think the replaced quartz was also broken, maybe I could have tried it before welding it, but I wouldn't know how to verify it, I think you can use an oscilloscope, or a tester able to read the frequencies, all things I don't have.

So even this motherboard, can come back among those to be repaired, or in the future it could go in a box, of motherboards from which to recover something, like a connector slot or other verifiable, in short I hope not.

I came back to the S.7, I had put as a card to try a ZIDA 5SVA-E, because there is a Cyrix M II-300 (233 MHz) and VIA VPX chipset, as configuration is slightly different from the ACORP, there are 32 MB of RAM, a VGA PCI 3D Labs Permedia 4 MB, a 4GB HD Fujitsu, an ISA SB vibra chip sound card, and Windows 98SE.

Started the PC, with a serial mouse 🖱 connected, I took a look at the programs present, some bench images are stored there, for example BMX, I use some, like CPU-Z, but I didn't do the bench, I looked at the info on the PC.

Later I started from Windows, the Speedsys 4.70 program, and I noted the scores: 167.67
Data Cache L1 64KB - 787.81 MB/s

Data Cache L2 512KB - 194.17 MB/s

Memory Throughput - 106.83 MB/s
After closing the program, the message appears that you can turn off the PC.

From then on, it was useless, any attempt to enter Windows, and after various tests, I decided to disconnect the Fujitsu disk, to connect the IDE CF 40PIN adapter with DOS.

In this way, I can do other benches, especially those of Phil's, I do the 2) and I have 297.3 as a score, I go to 3) and get 162.6, with the 4) instead the problems begin, manifest blocks or the exit from the program with the return to the menu, in short in fact it is a bit hot, but in my opinion not to the point of burning.

For this reason, I don't think it's a good idea to put the 333 (263 MHz), I remember it had some problems, but I thought it was due to the chipset, since the other VPX (ACORP) was more or less the same.

Maybe I'll try to do some tests, with some modifications, changing cards or something else, but I wouldn't be surprised if nothing changes, a test I'll do will be the change of RAM, I remember that I couldn't go beyond 32 MB, here's this is a further problem that I couldn't solve, maybe I didn't have suitable RAM, but I think I tried some RAM, removing them from other PCs and of higher capacity, it didn't work because I've never seen more than 32MB, then it could be the BIOS that doesn't read correctly, even the speed is currently wrong, The Cyrix M II-300 is seen as 6X86MX-266.

For this, I could fix it with an update, but if I do it will be later, for now it is not important that the CPU is read incorrectly.

I performed some tests, on the ZIDA 5SVA-E motherboard with Cyrix M II-300 (Black), taking advantage of the cooler temperatures, I ran all the other Phil's benches, obviously yesterday I had it heated up before starting to do the benchmarks!!!

I put the results here, so that I can compare them with those of the Cyrix M II-333@300 that I have on the ACORP motherboard, the difference between the two cards is minimal, different VGA and RAM of 32 and 128 MB, then the rest should be the same, see chipset VIA VPX and SDRAM, I point out that I could have used 72 PIN RAM, but with the modules that I have available, I could reach a maximum of 64 MB, while with SDRAMs I get to 128 MB, or even 256 MB ? (Which I've never tried).

Let's see Phil's scores:

2) 297.3 | 3) 162.6 | 4) 49.8 | 5) 65.7

6) 25.1 | a) 304.86 | b) 79.80 | c) 40.0

D) 18.4 | e) 40.0

Later I will see to go and recover those of ACORP, just to understand if and how much difference there is. (?)

Currently, there is the BIOS with which the motherboard arrived, it is probably the original one, I think I will update it to a later version, because I would like to correctly recognize the CPU, and because later I want to try the Cyrix M II-333 using the multi 4X with FSB 66.

Chapter RAM, I currently have 32 MB, many for DOS, but it could be few in Windows, in particular having Windows 98SE, they are enough to work and use some program, in reality if I had at least 64 MB it would be better, so I start trying various PCXXX RAM, with the 64 MB ones it reads only 16 MB, with the 128 MB ones instead only 32 MB, with a 256 MB double-sided one, the PC does not start it crashes on some post codes, but with all the double-sided RAM it is the same (lower capacity), so it seems impassable to have more than 32 MB with SDRAM.

Among the RAMs that I keep aside, there is a 64 MB EDO SDRAM, single face, well I try that one and it works!!!

So there must be something in normal RAM, which obviously does not digest, the same problem is on an LS i430VX, maybe I can see if this EDO RAM is read in full, even there.

Finally, a further update, looking at the VCORE jumpers, the 2.8 V is selected, the PC works but...

It should be 2.9 V, this could explain, because every now and then some problem or blockage occurs, that 0.1 V more could give stability, and eliminate various operating problems.

PC@LIVE wrote on 2025-10-28, 14:32:

Looking at the files contained, regarding the updates, I noticed that it would seem the same for both motherboard models, that is, both the 5SVA and the 5SVA-E, use the same BIOS (?). Looking on the Internet, I found some info about it, it says that the BIOS is not the same for 5SVA and 5SVA-E, in short, if there was a doubt, now it has not disappeared.

As far as I know, there are references online that the BIOSs for 5SVA and 5SVA-E are different, and indeed the BIOS files for 5SVA have the label 5svAxxe.bin, whereas for 5SVA-E is in the name 5svExxe.bin.
So we can assume that even though both boards use the same chipset and are similar in many ways, there are some differences in BIOSes.

PC@LIVE wrote on 2025-10-28, 14:32:

Other info about the memory, it says that the maximum capacity DIMM modules are 64 MB, in fact I don't remember if in the past I tried 64 MB SDRAM, eventually I could try, if you want you could use the DIMMs together with the SIMMs, it's not something I would do, but I could do if you need to have more RAM than 64 MB.

With BIOS v.1.41, I have a 128MB SDRAM module on my board and as you can see in the images in the attachment, it is properly recognized and fully usable. But I just have a version of 5SVA without an E and the latest BIOS v.1.41.
For your version of 5SVA-E, the last BIOS is 1.40, and I don't know if the support for large SDRAM modules is solved there in the same way as the non "E" version - (which should hold up to 256MB modules)?.
I dug up my old "buddy" and ran Speedsys in a hurry, the results are on screen. (HDD is Seagate 40GB and due to the small 256kB L2 cache and the large SDRAM module, the L2 cache runs in write-through mode and not write-back, so the performance is lower).

Ydee wrote on 2025-11-11, 16:36:

As far as I know, there are references online that the BIOSs for 5SVA and 5SVA-E are different, and indeed the BIOS files for 5S […]
Show full quote

PC@LIVE wrote on 2025-10-28, 14:32:

Looking at the files contained, regarding the updates, I noticed that it would seem the same for both motherboard models, that is, both the 5SVA and the 5SVA-E, use the same BIOS (?). Looking on the Internet, I found some info about it, it says that the BIOS is not the same for 5SVA and 5SVA-E, in short, if there was a doubt, now it has not disappeared.

As far as I know, there are references online that the BIOSs for 5SVA and 5SVA-E are different, and indeed the BIOS files for 5SVA have the label 5svAxxe.bin, whereas for 5SVA-E is in the name 5svExxe.bin.
So we can assume that even though both boards use the same chipset and are similar in many ways, there are some differences in BIOSes.

PC@LIVE wrote on 2025-10-28, 14:32:

Other info about the memory, it says that the maximum capacity DIMM modules are 64 MB, in fact I don't remember if in the past I tried 64 MB SDRAM, eventually I could try, if you want you could use the DIMMs together with the SIMMs, it's not something I would do, but I could do if you need to have more RAM than 64 MB.

With BIOS v.1.41, I have a 128MB SDRAM module on my board and as you can see in the images in the attachment, it is properly recognized and fully usable. But I just have a version of 5SVA without an E and the latest BIOS v.1.41.
For your version of 5SVA-E, the last BIOS is 1.40, and I don't know if the support for large SDRAM modules is solved there in the same way as the non "E" version - (which should hold up to 256MB modules)?.
I dug up my old "buddy" and ran Speedsys in a hurry, the results are on screen. (HDD is Seagate 40GB and due to the small 256kB L2 cache and the large SDRAM module, the L2 cache runs in write-through mode and not write-back, so the performance is lower).

Thank you for the suggestions, I already knew about these differences, because we talked about them with Jan and others, in fact it was a bit strange that the cards are almost the same, but the BIOS is specific for one or the other model, even if in some notes of the BIOS files, it is written if it is possible to use them also on the 5SVA-E, in any case I do not think I will update, without first saving 🛟 of the one currently present on the motherboard, and then updating with Version 1.40, which has the recognition of the latest CPUs, and other corrections.

Honestly I don't know if updating, I would solve the RAM problem, which is now also almost solved, with the 64 MB EDO module, of course for me it would be better to have a 128 MB RAM, but I don't think it's needed or makes a difference, and as I said I prefer SDRAM, instead of the 72 PIN SIMM, then I'll try again some of the 128 MB modules, if they go it means that it was the original version of the BIOS (1.00), which was limited to 32 MB with the PC1XX SDRAMs, I'll see if the update also solves this problem.

I momentarily go to an SMT 486 PCI motherboard, it's the only one I have, I put the CPU myself, because I wanted to recreate the 486-DX4-100 that I had years ago, it was slightly better than this, but all in all recovering this, I would have something quite similar.

In my opinion, this card has been washed, but it has not dried well, in the large chips (chipsets and others), the pins are very dark, and in the sockets of the cache chips, I notice green, for this reason, I decide not to try it now, I will do it later, after cleaning some areas, for this I remove one of the L2 cache chips, to see under the chip how much green oxide there is (?), in practice it is almost all oxidized, there is not much, but the contacts have a dark and greenish color, instead of being silver.

The same chip, has several oxidized pins, once removed, I proceed to clean them, for about half of the pins, brushing them and sanding them, a copper color appears, instead of the silver color they normally have, maybe here I would explain the green where it came from, if I wanted I could make them all copper color, and then stagnate them, so as to make a thin tin plating, but I don't know if it's better to leave them like this.

Last work done, the polishing of the pins of the big chips, chips labeled ALi, they have a very dark color, I think it was not dried well, and that the water left between the pins has oxidized them, the only way I found useful to revive them, is to pass a thin abrasive paper on top, the final result is much better than before, I wanted to remove that oxide, to prevent it from creating a bridge between the various pins, and to prevent them from corroding and interrupting each other.

Now I should polish the inside of the cache socket, plus the other three chips that are still to be disassembled, with the right welding station, the hooches would need to be changed, but to avoid unnecessary damage, I prefer to try to clean them with a pin, then I check if the pins lead, if so I should prepare the card, for the start, there are jumpers that need to be moved, but maybe to try, I will use a slower CPU, like a 486 SX or 486 DX, later if I see the BIOS screen on video, I would switch to CPU 486 100 MHz or more.

Ydee wrote on 2025-11-11, 16:36:

As far as I know, there are references online that the BIOSs for 5SVA and 5SVA-E are different, and indeed the BIOS files for 5S […]
Show full quote

PC@LIVE wrote on 2025-10-28, 14:32:

Looking at the files contained, regarding the updates, I noticed that it would seem the same for both motherboard models, that is, both the 5SVA and the 5SVA-E, use the same BIOS (?). Looking on the Internet, I found some info about it, it says that the BIOS is not the same for 5SVA and 5SVA-E, in short, if there was a doubt, now it has not disappeared.

As far as I know, there are references online that the BIOSs for 5SVA and 5SVA-E are different, and indeed the BIOS files for 5SVA have the label 5svAxxe.bin, whereas for 5SVA-E is in the name 5svExxe.bin.
So we can assume that even though both boards use the same chipset and are similar in many ways, there are some differences in BIOSes.
………..

Sorry but I only realized after answering that it was you and Jan, who suggested the existence of new updated and corrected BIOS.
Since I see that you have a Tomato logo, which would be equivalent to ZIDA, I wanted to know if you are interested in the original BIOS that I have in the motherboard, that is, version 1.0, if maybe putting it here, someone can download it.
I don't know if you're interested, but I have a ZIDA Z4DVP motherboard (if I remember correctly what it's called), for 486 VLB, which I can easily restart, has a problem with the L2 cache, I don't know if it depends on a broken chip, but I don't think so, because if I'm not mistaken, I had tried 4 others, and even those didn't work, while in another card it did.

Soon I will update the BIOS on the ZIDA 5SVA-E motherboard, I had downloaded all the versions from the Tomato (ZIDA) website, but I chose version 1.40, special for the 5SVA-E, in short there is the support of new CPUs, such as AMD K6-2 (I think also K6-III) Cyrix MII etc...
These two types of CPUs are the ones that interest me, first to try to speed up the PC, and then to make some bench comparison.
Of course in addition to the BIOS files, I downloaded the HWflash V.8 file, which is needed for the update, but before updating, I will make a copy of the original BIOS, which should no longer be useful, but in case of problems, I can reuse it and try to update with other files of different versions.
If it's a fast enough job, I could try to complete the work on the 486 PCI motherboard, I have to scrape the green in the L2 cache sockets, I thought of using a pin, or a small screwdriver 🪛, the problem I think is not the visible part, but the internal one, maybe it would be better to sand, but the space is so tiny, that I don't think it's possible.
But I would like to be able to try it as soon as possible, so I will try to spray some IPA on it, before reassembling the chips, in their place, then the rest should be, prepare the card at the first boot (after a long time), and hope to see a BIOS screen on the screen.

Finished a little while ago the BIOS update on the ZIDA 5SVA-E motherboard, initially I had a problem saving 🛟 of the BIOS 1.0 (the original one), but after a few attempts I solved it using the same AWDFLASH of the ACORP BIOS, those Version 8. X that I had downloaded from ZIDA had strange blocks, which at a certain point I feared having to disassemble the chip, to reprogram it with the USB programmer.
Lucky 🍀 that I tried the ACORP one, which seems to work much better, so first of all 😨 I saved a copy *. OLD (Version 1.0), then I turned off the PC and after restarting it, I programmed with version 1.40 (special for 5SVA-E cards), using the 5SVE140E.BIN file, when asked if I wanted to save 🛟 a copy of the current one, I said yes 👌
It would not have been necessary to save a second time, but in case of problems, I would have understood if the save had gone well, or not, however later after finishing he asked me if I wanted to go out or restart the PC.
When you restart the PC you don't notice anything new, why not buy the CPU and RAM, except that the version is now 1.4, however from the second BIOS screen, I see the correct CPU identification appear, like Cyrix M II-300 (or IBM 6X86MX-300), in short everything went well 😊
But now that the CPU recognition works, in the right way, I try to change the memories, to see if maybe they are detected correctly, I try a 64 MB module, previously it was detected as 16 MB, now it works! Reads 64 MB correctly!
But now I have the chance, to try to see if it also detects the 128 MB ones, so I remove the 64 MB one, and put a single face PC133 128 MB, and read them!!!
I haven't tried the 256 MB ones, because honestly I'm not interested in having more memory, but I think a single face could be detected in full, I haven't tried the double-sided ones, but even here I have no interest in using them there, they will go to the next generation PC.
That's it for now, the next step could be done, with a different motherboard, a LuckyStar 5VX1C, Socket 7 chipset VX that has the same memory problem, does not detect SDRAM for more than 32 MB, I will try the 64 MB EDO SDRAM module, I think it will work (let's hope so!!!), in that card I had updated the BIOS to solve the problem, but it didn't work, maybe maybe there could be a possibility to solve (?) This problem?

PC@LIVE wrote on 2025-11-11, 19:36:

Since I see that you have a Tomato logo, which would be equivalent to ZIDA, I wanted to know if you are interested in the original BIOS that I have in the motherboard, that is, version 1.0, if maybe putting it here, someone can download it.
I don't know if you're interested, but I have a ZIDA Z4DVP motherboard (if I remember correctly what it's called), for 486 VLB, which I can easily restart, has a problem with the L2 cache, I don't know if it depends on a broken chip, but I don't think so, because if I'm not mistaken, I had tried 4 others, and even those didn't work, while in another card it did.

Thank you, but the only Zida Tomato board I have is just 5SVA rev.1.2. The others (BX98-CT and BX98-3D) I was forced to send in due to lack of space. I have the Tomato board logo because of my weakness for outsiders, and of course Zida was no match for giants like Asus, Gigabyte, Abit and so on. But some pieces of hw from them I enjoy and 5SVA is one of them, although there is nothing special about it and it is built on the overlooked VIA Apollo VPX chipset.

Ydee wrote on 2025-11-12, 16:35:

PC@LIVE wrote on 2025-11-11, 19:36:

Since I see that you have a Tomato logo, which would be equivalent to ZIDA, I wanted to know if you are interested in the original BIOS that I have in the motherboard, that is, version 1.0, if maybe putting it here, someone can download it.
I don't know if you're interested, but I have a ZIDA Z4DVP motherboard (if I remember correctly what it's called), for 486 VLB, which I can easily restart, has a problem with the L2 cache, I don't know if it depends on a broken chip, but I don't think so, because if I'm not mistaken, I had tried 4 others, and even those didn't work, while in another card it did.

Thank you, but the only Zida Tomato board I have is just 5SVA rev.1.2. The others (BX98-CT and BX98-3D) I was forced to send in due to lack of space. I have the Tomato board logo because of my weakness for outsiders, and of course Zida was no match for giants like Asus, Gigabyte, Abit and so on. But some pieces of hw from them I enjoy and 5SVA is one of them, although there is nothing special about it and it is built on the overlooked VIA Apollo VPX chipset.

I thought that maybe somehow you were linked to the site, and you had a collection of ZIDA motherboards, exactly I don't know if I have other ZIDA motherboards, but I definitely have a couple, the 5SVA-E was bought many years ago, because I wanted to see if it was faster than the ACORP 5VIA3P, looking at the site I think there are some boards to add, for example the 4DVP, which is a 486 VLB.
Among the non-branded cards, I have several PCChips, some are good cards, others are not so good, however I like them because most of them are quite unusual.

I did some short tests, to eliminate the errors present in the first BIOS screen, I managed to delete them all, except one.
There was a little low battery 🪫, and it didn't store the BIOS settings (accessed via Delete), the 1.44MB floppy disk, I use it occasionally, so I removed it from the BIOS, but I haven't tried to do a CMOS reset yet, I don't think it's possible to eliminate the remaining problem.
With the BIOS REV:1.0, the memory at startup was counted three times, with that of now (1.4), instead the count begins and then at a certain point jumps directly to 131072, then at the bottom you read the message "Memory test fail".
I think it reports an error, I changed RAM with another 128 MB single face, but the message 💬 remained.
Even if the PC seems to work, but without the HDD with Windows 98SE, I can't try to start some diagnostic programs, just to understand if there is actually a problem with the SDRAM modules, or it's the new BIOS that reports an error, which in reality I don't know if there really is 😨.

I solved the problems of the RAM that failed the test at startup, after several tests I decided to return to the 64 MB EDO SDRAM, because it works very well, while the normal 128 MB PC133 SDRAM that I used, even if then the PC works, it gives an error, and you have to wait to press an F1 key (or Delete), to be able to complete the OS startup.
I haven't tried SDRAM PC66 or PC100, because I could have them but they are in some PC, I don't know exactly where, however I tried the double-sided ones and they don't work.
But I tried the other PC with MB ACORP, unfortunately there is a problem, even manually entering the C. H. S., I can't get it started 🛫, this is because with the automatic recognition of the disk, it doesn't automatically detect the values, in short, maybe, I'll be forced to go back to the previous version, or maybe try to recover ❤️‍🩹 an HD and then put Windows 98SE.
Speaking of DOS, I read that in Windows 95 there is a version 7 of DOS, I wonder if it can be extracted, to be used without Windows (?).

Now I have between my legs, the SMT 486 PCI motherboard (Terminator !!!), I removed the second L2 cache chip, it was definitely better than the one before, however almost all the pins are very oxidized, I revived them with fine abrasive paper, and I think I will do the same work on the other two and on the TAG chip 🏷, at least in this way I should improve the contacts with the socket, about this, inside the sockets there is a lot of oxide, I removed a part by scraping with a pin, I hope to have removed enough, but given the size, the alternative In case of problems, it would be to change them with new ones!

Among the controls I performed, there is that of the jumpers, this motherboard uses a very complex system, quite common even in other 486, nothing to do with automatic CPU recognition, there are jumpers for multi FSB frequency cache etc...

In practice, even if the CPU is at the same frequency, depending on the brand it has different settings, I don't know in fact if this doesn't prevent the operation, but you can see that at that time, the 486 were different in something depending on the brand, perhaps to avoid making them the same and having legal problems.

From what I've seen, the jumpers are set up for an Intel 486DX2-66 (I think also the same as the DX-33), I don't think I have a free DX2-66, but I definitely have a DX-33, and I'm thinking of using it as a CPU for the first boot test, later if I see that it works, I'll try to change all the jumpers, to replace the CPU with an AMD 486DX4-100, I would evaluate later whether to change again ️ CPU, to choose between Intel DX4 100 , and AMD 486DX4-120 or 5X86-133 P75, maybe among these three, the fastest one would be the best, some manage to make them go to 160 MHz (4X 40), but the PCI would also go to 40, or the PCI works at double speed (?), so it would be 80 MHz!

Looking at the BIOS chip, the pins of both the chip and the socket, do not seem oxidized at all, so I do not remove it, if instead I notice the absence of post codes, I would try to remove it, to do the cleaning treatment and oxide removal.

Needless to say now, but this would be among the 486 I prefer, since most are all DX2-66 VLB, later I'll see to update some of those, with faster CPUs, one for example would go to DX2-80, another to DX4-100, the main problem is that not all have the voltage regulator, so only 5V CPU, for those who have it, well keeping a 5V CPU doesn't seem like a good idea to me.

The only thing you have to do later, is to choose the cards to use, for the video card, I have kept for a long time ⏱ an S3 Trio32, precisely a Miro Crystal 12SD-PCI, it has 1 MB of RAM expandable to 2 MB, a card that I occasionally use in MB tests, but that I would not put on recent socket 7, as a sound card instead I would go on an ISA or a PCI, it depends on how many free PCI slots you need, of the three I will occupy at least two (VGA and USB PCI card), so maybe the best solution is an ISA sound card maybe of the type without a controller CD on board.

Another motherboard that I have to try again these days, is an S.423 with RDRAM, it is an Intel D850GB (Garibaldi), if I remember correctly there is a P4 Willamette 1.6 GHz (256 KB 400 FSB), the card is in excellent visual condition, but even if it starts, it can't get to the BIOS screen, I don't remember well but it seems to me that it doesn't beep at all.

For the RAM I used two RDRAM PC800 not ECC of 128 MB each, plus two terminators for the other two empty benches, I also checked the jumpers and everything seems ok.

In the tests carried out some time ago, the PCI post card, displayed the codes D4 D3, D4 has to do with the memory, and looking at the connections, the RAMs are connected directly to the i850 chipset, so if the RAMs are working I would suspect that the problem is elsewhere, and being connected directly with the i850, I would think that there could be a problem there, provided that it is not another problem.

Thanks to Jan's suggestion, I saw that the PCI post card can display all the previous post codes, so I thought I'd try to see if the one that precedes the D4 and D3 codes has a logical sequence, in case there isn't, maybe it could be an incorrect or poorly executed BIOS update.

Of course, I could check the content of the Chip, unfortunately it is welded to the motherboard, I have no idea if it is a solution to save money, since the motherboard looks like a basic model, that is, with only the bare minimum, you see a lot of gaps, and many are predisposed for various chips, for me it is not a big problem, what is missing I add it with PCI cards, surely a PCI sound card should be added, then maybe if you need a PCI LAN, while for the video card there is an AGP slot, to start I have a 64 MB Radeon 7000 (? It seems to me), possibly later I can always change it with another one.

All the info and photos of an equal card are on TRW here:

https://theretroweb.com/motherboards/s/intel- … di,-garibaldi-c

On the Intel D850GB I anticipated the tests to today, I have to specify some things, the CPU is P4 1600/256/400/1.75V, the RDRAMs are Samsung MR16R0828BN1 800 -45 128MB/8, the AGP video card was Radeon 7000 32 MB, but it doesn't matter because I tried a 32 MB TNT2-M64, it's a pair of VGA PCI, nothing happens, whether there are VGAs or not.

As I said I turned on the PC, and the PCI post card, it shows the d4 and d3 codes, scrolling through the previous codes, I see these: d4 d3 d2 d0 14 d1 dd, very little compared to what I imagined, of course no beep.

The LEDs of the keyboard when the PC is turned on, so nothing strange, but then almost immediately, arrived at d4 d3, the PC interrupts the boot sequence, it is not possible to do the keyboard reset, pressing the three keys at the same time.

I wonder if starting without RAM, I can make some beeps, empty the counters and start, the codes 01 dE appear, followed by three beeps, then after the beeps the codes become a9 01, the backward sequence is like this:

A9 01 dE dF d3 d2 d0 14 d1 dd

Finally I wrote down the voltages on the mosfet, maybe there is a low voltage problem, on two mosfets near the CPU, I read on pin 2 a voltage of 1.36V, while on a third larger, on pin 2 I have 11.45V, this makes me suspect the power supply because on the 12V I have 11.73V, however on the two large inductors I read in one 1.42V and the other 1.72V, so this would be the voltage of the VCORE (?).

Considering that all the voltages seem to be more or less normal, I would say that there is nothing abnormal, and this would make you think of a non-hw problem, yes I did not check how many Volts there are in the RDRAM, but there is a suspicion that something happened, maybe it is the result of a power outage during the BIOS update, or an incorrect programming, checking the content is impossible, because the chip is welded, who has a hot air welding station, solves the problem, unfortunately I don't have it.

On the Intel D850GB I did other tests, I tried to turn on with the 4 PIN (+12V) disconnected, I expected that there would be no voltage in the VRM area, well to my great surprise it is not like that, there is also in the MB manifold the +12V!

So I also disconnect the other one, the 6 PIN (type AT) with the +5V and +3.3V, here too I measured in the MB connector, and there are both voltages, in practice I think the ATX 20 PIN alone is enough, to make the card work!

Maybe it was made like this, because initially the suitable power supplies, with the two 4 and 6 PIN connectors, were not widespread, and they would have forced to buy a new ATX power supply, the motherboard was also sold with RAM, in short at the time it was not really cheap to buy a P4.

The purpose of disconnecting the auxiliary connectors, was to see other codes, or listen to some beeps, unfortunately nothing happened.

Further proof, I had the motherboard warmed up for a few seconds, and I touched all the big chips, to see if anyone burned, no one shows temperatures that suggest a failure, they are all cold, even the heatsink of the chipset is strangely cold, otherwise why would it have a heat sink, here maybe this is the solution, I understand the inactivity, but I expected to feel a certain heat.

So I think I've finished with this card, probably the problem is in the i850 chipset, of course the doubt remains about the BIOS, which it was not possible to verify, but in case you can look at the content, and it was intact, then it would be in my opinion very likely that there is a failure in the i850 chipset.

When starting the LEDs of the PCI post card, all those of the voltages light up, and also the CLK one, then the RESET one flashes, as soon as RESET is turned off the IRDY and FRAME LEDs flash simultaneously, and then when the two are turned off it stops on d4 d3.