Further investigations on the motherboard 386/25, coming from an HP Vectra, one thing that I found very interesting, is in the Slot ISA area, there are points where you can measure the voltages, of course using the post card, we have LEDs for every single voltage 😬, but sometimes it can happen that you don't have it within reach 🐾, and it should be measured on the ISA slot, in this way you can easily measure if the voltages are present and correct.
I saw the speed in ns on the RAMs, there are 70 and 80 ns chips, in theory so they should be 80 ns RAM (I guess), since the PC is a 25 MHz this speed should be enough to use low WS (0? 1?), I didn't quite understand which are the 4 Cache chips (32 KB), and I don't know if there is a TAG chip, however I didn't look carefully at some small chips, maybe maybe 🤔 they are those.
Moving on to the PS/2 connector area, I will try to look carefully at the mouse connector circuit, I don't know if it is possible to replicate it, but in case it could be something 😨 interesting to build, because it would be a valid alternative to serial ports, in many old PCs, in fact the disk controllers and ports, were on two ISA cards, and therefore you could do without one of the two, obviously the card with serial ports.
Finally the connector of the proprietary power supply, you can read P1 and P2, the P1 is three PIN, and the three PINs are connected to three wires of different color (black yellow red), the order of these wires may be different, but basically it is the +5V of the +12V and the ground wire, so if we had a normal power supply, it would not be so difficult 😩 to connect via an adapter.

Just to take stock of the situation, for now I don't have enough time to do the boot test, with the HP 386/25 PC power supply, and later with the motherboard.
I have no idea 💡 how long it will take, it is likely that if I were to find lines beyond tolerance, I would have to investigate thoroughly to try to fix them.
Some time ago I fixed a Gigabyte GA-7VAXP, and I found the photo of the lot of which it was part, there is also the ABIT and a strange PCChips i810 (without slot), of these two one has been almost repaired (ABIT), the other instead not due to lack of spare parts, which I will have to order in the coming months.
Having little time available at the moment, I prefer to try the motherboards that I have repaired in the past, or that do not need repairs, at the moment there are a maximum of ten, but for some you need a reduced ATX to ATX-adapter, in particular I have some HP Bach boards, which should be tried.

Speaking of motherboards that I bought recently, there are some that I can't repair at the moment, others haven't been tried yet, in short, I need some free time, which unfortunately I don't have, from Monday to Friday it's impossible for me, the only days I could therefore be Saturday and Sunday, and a few minutes are enough for some tests.
From the pictures you can see a 286 motherboard with Headland chipset, it's a 12 MHz and if everything is ok and works well, it would be the slowest 286 I have, I have another 16 MHz, but there is a non-standard AT power supply failed, which I should repair.
For my 486 Terminator II with AMD 486DX4 100 MHz, today I received an ISA sound card, a Trust Sound Expert De Luxe Wave 32 3D, with all the software kit and manuals.
Regarding the motherboards with only ISA slots, I practically ran out of ISA VGA video cards, unfortunately today you can't find anything at normal prices, cards like the Trident 8900 or similar, or the ET4000 or equivalent in performance, they are hard to find and cost (not little!).

For the moment having little free time, I am gathering various ISA cards, for PC up to 486, since I recently fixed some, my stocks have run out 😰, being cards now almost unobtainable, those for sale have prices a little too high (in my opinion!), but it may happen to find some opportunities at low prices.
As you know (see signature), I have a collection of PCs that goes from 286 onwards, in fact I also have an XT that I have never tried, maybe one day I will try it, but I have others to try, a 286-10, a 386DX25, a 486 with UMC CPU, then I have various 486 with various cache problems, problems that should be solved to get the maximum performance.
Unfortunately 😣 by now for this kind of ISA motherboards, even if you find second-hand boards (in good condition), find everything else, various memory boards etc..., it is quite difficult if the budget is limited, towards the end of the last century, it could happen that someone gave them away, or gave away the entire PC (especially if it broke down!).
Fortunately over time I found several used motherboards, even if they required some interventions, some welds or repair of the tracks (corroded by battery acid), but at the end of the work there was still a nice 🤩 satisfaction, as soon as it displayed the BIOS screen.

As far as it matters, the next motherboards I will work on, will all be from the 90s, maybe not everyone knows it but they are the PCs I prefer, of course their computing power (limited), can make them a little slow, if you don't have much RAM and the frequency is low, from the PCs I had (and that I still have ⚓️), a 486DX2-66 can be used with Windows 95, but having at least 16 MB of RAM, with 8 it works but not at the best!
Among the various 486, I temporarily postponed the work on the Terminator II with DX4-100 (AMD), I recently recovered an ISA sound card, which I will replace with the temporarily used one (SB16), the sound card is a Trust Sound Expert De Luxe Wave 32 3D, I think it is comparable to a SB32, and it has a wavetable (integrated), to complete the updates, I will see to find two RAM chips for the video card, it would not be necessary to increase it, because I have 1 MB, but I saw that the cost of a small batch of RAM chips was not exaggerated, so I think in the next few weeks to order them.
I will also try to gather everything necessary to test the 286-12 Headland, and the 386DX25 HP, I would have the stocks of ISA cards a little lacking, in particular VGA and controller, I recently recovered something, but I have one or two at most, this could greatly limit the possibilities of repairing ISA motherboards in the future, although perhaps it could be solved with the boards made (replicas) following the original traces, I have seen several some are even slightly improved clones, of motherboards now unobtainable in good condition, because most have been corroded by the acid lost by the battery.

Chkcpu wrote on 2025-10-26, 18:19:

I will look if a further 5SVA-E BIOS upgrade is available, or can be made.

Jan

Ciao Elio,

Last October you, Ydee, and me talked about the Zida 5SVA(-E) BIOS.
You chose the v1.40 BIOS for your 5SVA-E board, and I promised to look for a later BIOS.

Well, I found an Award Rel. 2.0 upgrade BIOS from Unicore Software for the 5SVA and I believe it will work on the 5SVA-E as well. This upgrade BIOS supports drives up to 128GiB/137GB and supports UDMA under Win98 as well. It also supports all Socket 7 CPUs, except the K6-2+/III+.
I have patched this 09/22/1999 BIOS to include support for the K6-2+/III+.

If you still have this board, could you test this 5SVA(-E) patch J.1 BIOS, and report how it works? Thanks in advance.

Greetings, Jan

Chkcpu wrote on 2026-05-17, 17:45:

Ciao Elio, […]
Show full quote

Chkcpu wrote on 2025-10-26, 18:19:

I will look if a further 5SVA-E BIOS upgrade is available, or can be made.

Jan

Ciao Elio,

Last October you, Ydee, and me talked about the Zida 5SVA(-E) BIOS.
You chose the v1.40 BIOS for your 5SVA-E board, and I promised to look for a later BIOS.

Well, I found an Award Rel. 2.0 upgrade BIOS from Unicore Software for the 5SVA and I believe it will work on the 5SVA-E as well. This upgrade BIOS supports drives up to 128GiB/137GB and supports UDMA under Win98 as well. It also supports all Socket 7 CPUs, except the K6-2+/III+.
I have patched this 09/22/1999 BIOS to include support for the K6-2+/III+.

If you still have this board, could you test this 5SVA(-E) patch J.1 BIOS, and report how it works? Thanks in advance.

The attachment 5SVA20J1.zip is no longer available

Greetings, Jan

Ciao Jan,
Yes, I remember that motherboard well, and after trying the new BIOS, I took care of other motherboards including some 486, however I intend to try this version 2.0 of the BIOS, but I will only be able to do it this weekend, because from Monday to Friday I am too busy at work.
From memory I don't remember if after the update I tried the multi 4X or other improvements, however I will review all the notes about that MB, just to understand if the new version of the BIOS improves performance, but this will be seen by comparing some benches (mostly those of Phil's).
Regarding the support of the K6+, a lot depends on the voltages that the board is able to provide, I remember very well that it makes 2.2V, but maybe it is possible that it can do even less, but from memory I don't remember if the regulators are linear or switching (?), in any case well I would use them in motherboards with FSB 100, here I have used so far a Cyrix MII-300 233 MHz, maybe not the best choice, but having almost a dozen S.7, I like to have some PCs with CPU not Intel or AMD.
Greetings

Chkcpu wrote on 2026-05-17, 17:45:

Ciao Elio, […]
Show full quote

Chkcpu wrote on 2025-10-26, 18:19:

I will look if a further 5SVA-E BIOS upgrade is available, or can be made.

Jan

Ciao Elio,

Last October you, Ydee, and me talked about the Zida 5SVA(-E) BIOS.
You chose the v1.40 BIOS for your 5SVA-E board, and I promised to look for a later BIOS.

Well, I found an Award Rel. 2.0 upgrade BIOS from Unicore Software for the 5SVA and I believe it will work on the 5SVA-E as well. This upgrade BIOS supports drives up to 128GiB/137GB and supports UDMA under Win98 as well. It also supports all Socket 7 CPUs, except the K6-2+/III+.
I have patched this 09/22/1999 BIOS to include support for the K6-2+/III+.

If you still have this board, could you test this 5SVA(-E) patch J.1 BIOS, and report how it works? Thanks in advance.

The attachment 5SVA20J1.zip is no longer available

Greetings, Jan

Ciao Jan,
Only today I found the time to download the BIOS for the MB ZIDA 5SVA-E, but due to various commitments, today I can't try it, but I'll see to update the MB as soon as possible, and I'll let you know if I notice any differences, doing the usual Phil's bench, although I believe that the results will be the same or very similar with the BIOS currently installed.

In the next few days I hope to be able to do the first boot tests of some dated motherboards, in particular there are a 286-20 and a 486DX2-66 VLB, I just checked who the manufacturers are, the 286 should be a PCChips M209, the other instead should be a Gemlight GMB486, maybe they are not high quality motherboards, but I hope they both work, because I like both and I hope 🤞 to enrich my collection of OLD PCs.

In a few days I should have between my paws 🐾, the motherboards of the previous message, the one that interests me particularly, is the M209 with 20 MHz CPU, from the photos it is not possible to understand if it has corrosion problems, due to the battery that is leaking acid, I hope 🤞 that the problem is not there, or at the limit it is not such as to compromise the operation of the motherboard.
Among the pages of the manual, there are some interesting things 🧐, first of all I notice that there is no 287, it is not essential if you do not use calculation programs, but if you need one, I think it must be at least 12 MHz, there are still various versions, which are slower, but even if they could work, I think they can slow down the calculations, since the CPU is 20 MHz, a frequency not common for a 286.
Another interesting page 🧐, is the one on the memory configuration, which should be from 512 KB up to 4 MB, normally 1 or 2 MB, they were common quantities at the time, but today if you can, I would recommend at least 2 MB or even 4 MB.

In addition to the two motherboards 286 and 486, there is a third motherboard 775 to try, and it might look like a very normal motherboard, but this ASROCK 775i65GV, is strangely particular, looking at the info available on TRW, it seems that the AGP is particular, there is a list of compatible video cards, but from what I understand, it is a type of AGP that works like a PCI, so definitely slower!
It therefore looks like a priority AGP port, which while making some video cards work, does not make them go at full speed, this is quite strange, since the card is relatively modern, I would have understood such a thing at the time of the P2 and P3, certainly not with the P4, in short, those who own such a card, can be quite disappointed by the change of VGA, I don't think you gain much by changing VGA, from the integrated one to the AGP one (compatible), it looks like a kind of remaque of those PCChips cards, known for promising high-level performance, while the reality is clearly opposite.
Another strange thing is that ASROCK is a cheap brand, but with some interesting solutions, for example the Upgrade series allows the support of the next generation CPU, through a special card and socket (Future Upgrade), that is, I can understand that there is an AGP-like Socket, but I don't understand why it is limited in performance, moreover there are MB ASROCK MB with AGP and PCI-E.

Today I received the batch of three motherboards, 286 486 and 775, the one in better visual conditions is the 486 VLB, in the 286 there is a bit of corrosion due to the loss of the battery (it has come off!), the 775 has some damaged pins and requires the replacement of some swollen electrolytic capacitors, maybe 🤔 managing to straighten the crooked pins, there are good chances that after replacing the capacitors, you can see a video BIOS screen.
I don't know if the damage was already present, or if it is due to the transport, if you want to have a replacement socket, it would be possible to replace it, because it is not of the BGA type, the individual PINs are welded on the back of the MB, those who perform micro-welding work, can replace it without resorting to special equipment, which instead are necessary when the Sockets are BGA.