I absolutely love these old Olivetti cases.

good luck repairing it!

pampilhoso wrote on 2021-07-14, 15:44:

I absolutely love these old Olivetti cases.

good luck repairing it!

Hey thank you! 😁

I’ve got a PCS 11 (the even smaller form factor version of the same PC) that I’m going to attempt to replace the PSU with a flexATX PSU.

My PCS 33 is fortunately still running on its original PSU.

I’d go with repair of the original PSU if possible, my PCS 11’s PSU is unfortunately beyond repair (at least by me, blown traces and ruined solder pads around mains components).

@paradigital
Hello 😀

Nice i didn't know this PC brand before i've got to admit haha, but it's really rare!

Okay that's neat, and may i ask why this model in particular? Does it fit the case? And i guess you will modify the cables because they don't have the same connectors for the mother board right?

That's what i'm trying to do, i've tested all of the components on the PSU board and i've found many that are leaky, i'm going to change them all and see if that changes something.

Ah, my father worked for Olivetti so all of my computers during my childhood were Olivetti. I currently own 5:

Quaderno PC-XT
Quaderno 33
Philos (Laptop)
PCS 33
PCS 11

As for the PSU, FlexATX is a form factor that happens to be around 1U in height so should fit in my PCS 11 case no problem. My bigger issue with the PCS 11 is that it’s a soft power switch built into the PSU, on a 386! I’m going to need to do something to power on, and keep on, an ATX class PSU. The internal power cable I’m just going to cut off the original PSU and solder onto the right rails of the FlexATX PSU. I won’t worry about -5v as I’ve tested the machine without it, and it’s fine, I won’t be using any ISA cards that require -5v.

I think a Micro ATX PSU would probably fit in the PCS 33 if the worst came to the worst, heck it would probably fit in the original PSU housing itself.

Wow what a collection! 😁

That's awesome really! And they do all work?

Okay that's interesting, i guess it's pretty much the same as the PCS33 inside? So should i try to get me a Micro ATX PSU and install it?

@Verax, if you have access to a MiniPro or similar EEPROM reader, it would be nice if you could dump your BIOS ROM, yours seems to be newer than mine at 6.03, mine is 6.01.

Here's the PCS 11 vs PCS 33. The 11 is just so small for the era, it's almost the form factor of a modern day USFF PC.

That's cool! It's almost the size of the PCS33 motherboard haha.

Okay so i see you didn't make the PSU change yet, could you show me the PSU you will use for this one please?

Same PCs that were on my elementary school about 1993-1998 in Finland when I was +7 y.o. starting school.
386 Olivettis were the first PCs I saw. I still remember those.

Olivetti PCs were not rare back in 1990s. In Finland the Italian brand was pretty common.
People bought Olivetti because they had produced typewriters which had a good name.
Olivetti computers are kind of integrated and fewer update paths for example cheaper SX-processor compare it to DX.

Few years later I had a change to buy schools old PCs when in secondary school 1999-2002 for about 5-10 euros when they removed them but decided that the monitor which had to be taken too was too heavy for a 14-15 year old. 😀

We played the gorilla skyscraper dos game. Those had Windows 3.11.
In secondary school it was counterstrike time in school if I remember correctly.

Found a better 386 DX 33Mhz in a dumpster few years ago was it 2018 or 2019.

@user33331 Hello 😀
That's a funny story, i wish i could go back in time and buy one of these too! :-p haha

Do you still use it for retro dos gaming? 😀

May i ask if you had a PSU to sell by any chance? ^^

So if i wanted to check the mother board with a modified PSU, what wires should i link to the motherboard connector for it to launch properly?

I made a quick Blueprint so it's easier to see/explain : Thanks for your help! 😀

I'm still trying to work out what is what, mainly with what you have as pin 21 and pin 22.

On my PCS 33, my multimeter shows the following:

P21 = 5.07v = P8 (PWR_OK)*
P22 = 5.19v = ??
P23 = -12.22v = P12 (-12v rail)
P24 = 11.75v = P10 (+12v rail)
P25 = GND = P3,5,7,13,15-17 (ground)
P26 = GND = P3,5,7,13,15-17 (ground)
P27 = GND = P3,5,7,13,15-17 (ground)
P28 = 5.09v = P4,6,19-20 (+5v rail)
P29 = 5.09v = P4,6,19-20 (+5v rail)

Quite what P22 is when it doesn't appear to be the negative 5v rail is perplexing.
I'm actually surprised that Pin 22 isn't -5v rather than the +5v it appears to be. So that's one oddity. * I'm also pretty certain that P21 is PWR_GOOD, which would be P18 on the ATX connector.

Okay 😀

Well it's pretty much the same for me here is my measures as well (On the left)

Yes something that we don't know yet about some wire i don't know which one though.
I've got 0 volts on Pin 22, i don't know why? (notice that my card and PSU might be failing, i'm still testing so i don't know yet)

Yes you are right the brown one is the PWR_GOOD! 😀 Although, on the ATX refering to the manual of my model it's the grey one that is the "PWR_GOOD" .

You are right, I meant P8 not P18 for PWR_GOOD.

The blue wire on the PCS 11/33 PSU is definitely -12v, I think your 26.4v reading was measured between -12v and +12v so is wrong.

The white wire on the PCS PSU has direct continuity to the -5v pin on the ISA slots, so I think it “should” be -5v. The fact that mine is +5v and yours is 0v suggests both are wrong. Given the relative scarcity of the use of -5v, I don’t own a single ISA card that needs it, I’d be confident of just leaving that pin disconnected.

Okay so we both agree on that then good! 😀

Okay so the blue must be the "-12v" right? I can't measure it for some reasons, but thanks clarifying this as well.

I got to say that i'm lost on the white one? On the other PSU the white wire is the "-5VDC" one but i don't think it's the same for the Olivetti's card.
So the white one should be powering the ISA slot?

UPDATE with all of the corrections :

I added symbols to where i should connect the wires together to make the PC start at least haha

And also, how do i do to start the PSU? Do i need to bridge two wires together like the green one (Which is PS_On) with another one?

So, i did test out with the wires diagram, and guess what? It worked as for launching the computer however, still nothing appears on the screen... I might try to change some caps on the mother board to see if it changes something, i'll let you know 😉

Here is the video of the first launch with the new PSU linked to the board :

https://youtu.be/R2N8b9CBLqM

Oh I've successfully booted my PCS 11 with an ATX PSU before with the pinout I described above. As my ATX PSU was newer than the ATX 1.x specifications it didn't have a -5v rail, so I left that out (P22).

I did this months ago mind you. I knocked up an adapter using a filed down du-pont connector for the end that plugs into the PC, and a female ATX connector to plug into the PSU.

I'm pretty confident that my issue is going to be finding a PSU that fits inside the small form factor of the PCS 11. So far I'm coming up short, even most 1U rackmount PSUs are too long 🙁

Maybe a picopsu would do the trick ?

Verax wrote on 2021-07-15, 12:59:

@user33331 Hello 😀 That's a funny story, i wish i could go back in time and buy one of these too! :-p haha
Do you still use it for retro dos gaming? 😀
May i ask if you had a PSU to sell by any chance? ^^

I never bought the Olivetti back then. I now have a generic "ACT-brand" PC-Chips 386 motherboard. It is better than Olivetti and has a removable processor socket with AM386 DX/DXL 33mhz (upgradable to 40mhz but speed gain is not much to bother.).
- It runs on a very common 200W "PC-TECH Taiwan" AT-power supply.
- I never use the 386 it works but it is slow, has only a floppy drive and memory is always full. It is in storage. The slowest I go is Pentium 1 (200/233mhz) with CD/DVD-drive as a vintage PC. Usually I use Duron or Pentium III.