I feel like I'm making some progress! 😀

Firstly, using Ctrl-Alt-Shift-Del to enter Extended Setup works! It's great to see this back again, as I thought I had broken something...
Secondly, my battery is definitely delivering 3V from the daughterboard onto the riser card. There is also a jumper fitted to the riser card, which I believe is necessary to connect up the battery. So I still don't understand why I get the flashing battery symbol, but I'm as sure as I can be that this bit is working OK.
Third - switching the floppy drive off and on again in Extended Setup has got it working again, just as you said it would. I can now boot into DOS (from the floppy) again!

I still don't really understand what the difference is between the Basic and Extended Setup screens. I can see the Extended screen has more options, but I can't really figure out why they didn't just go with one comprehensive screen! Also there are some strange differences:

- In the Basic setup screen, the time and date are shown as not set. However, if I go into Extended Setup they appear (and seem to be retained correctly after switchoff).
- In the Basic setup screen, the floppy drive is shown as "Y" and I can even set the drive size (which I assume is 1.44MB). But in the Extended screen the floppy setting is blank, and I can't alter it.
- The Hard Disc is kind of the reverse of the above. On the Basic Screen it just says "Y". On the Extended screen is says "Y - 1 040MB" which I think shows it has auto-detected the right size (I don't seem to be able to change it). However, on boot I still get "Not present" for the hard disc.

At the end of the boot sequence it still reports "Configuration error" but it's not clear what the error is. I wonder if the CMOS chip is actually damaged? Does anyone know what type it is (or where it is?)

I think I know what the problem is - some parts of the CMOS ram are corrupt and I need a utility program to repair them. I tried using the Olivetti setup disc found here: https://www.minuszerodegrees.net/manuals.htm#Olivetti
...but that's for an M300-15 which is a slightly different model (the PCS33 is an M300-02, I'm not sure exactly what a PCS11 is). The software generally runs, but when I go to the Setup Utility part, I get an error message saying it's not compatible with this system.

Does anyone have a floppy image for a setup utility for the PCS11/PCS33?

I found the "GSETUP" utility here: https://www.uselesssoftware.com/category.php/ … ities?start=310

It's not an Olivetti utility, it's generic (that's what the G stands for).

It seems to work, in that the "Not present" message has gone away and now the machine is looking for the hard disc. I haven't plugged it back in yet, but I have some experimenting to do!

The PCS11 is a tiny little small form factor PC - same 386SX-16 and general architecture as the large boxes. I'd love something like that, if only you could get them with something with more grunt than the 16MHz SX.

A further update on this - the machine is now running quite well and I have managed to install a CF card. I have configured the BIOS to expect a "Type 3" hard disc, which is 120MB, and have formatted a 512MB CF card to that size. It all seems to work! The GSETUP utility was essential in getting to this point.

There's only really one remaining issue, which is that for some reason the BIOS seems to be looking for 2 drives, and reports a fault when it doesn't find the second one. Using GSETUP I have of course specified that the second drive is not present. I think this fault is probably only fixable using the original Olivetti utility disk which nobody seems to have. Incidentally this is an identical issue to the one already reported on Vogons here: How enter Olivetti PCS BIOS setup?

Hello everyone, I am looking for the types of ICs and the transistors/mosfets of the power supply from the olivetti M300-02 who refers to this thread because over time they have been erased. Thank you in advance .