Hi peda126,
if you are still looking for the manual you can download it from web.archive.org.
https://web.archive.org/web/20180107113509/ht … oard_manual.pdf
If that doesn't work for you I can give you a copy. Have downloaded it some time ago.
Please be aware that there are several different versions of the TC40 mainboard, sometimes referred to as Level 1 to 5 (written in copper above the cache socket). There's also a label next to the RAM slots that says "TC40 Bxx" where xx can be e.g. 11 or 20. I have seen two or three different numbers there already.
The main point is that it is possible that your specific board only supports 5V CPUs, like mine did (came with a Pentium Overdrive 83MHz 😉. This is because they omitted the 3.3V regulator (a 3pin TO-220 next to the QFP-196 CPU socket) and some passive stuff. Luckily, this can be added without problems. You also have to set the according large jumperblock next to the brown fan header/PSU connector to the left side, otherwise the CPU will still get 5V from the PSU. Alternatively they have added a six pin connector like the ones for the PSU right next to the jumper. There you can input 3.3V (or whatever you like) as well (3 pins Vcc, 3 pins ground).
On my board there's a AMD DX4-100SV8B working right now. Although the BIOS doesn't tell the right name at the boot screen it works without problems as far as I have tested it.
There's only one little thing I might fix some day: due to different pinouts of 486s (intel, AMD, cyrix) the CLKMUL pin (pin R17 of socket 3) of the newer ones isn't connected to a jumper or anything (at least on my board revision) leading to the fact that you are fixed at a x3 multiplier on those CPUs (since they want a specific level on that pin for setting the "correct" multiplier which the board doesn't supply). That means for example that a AMD DX2-66SV8B runs at 3x33MHz and not 2x33MHz as it should (has internal pull-up -> x3, needs external ground for x2, tested). A DX5-133 would also run at 3x33MHz out of the same reason (internal pull-up -> x3, needs external ground for x4, untested).
If you don't want to modify the board there are also some cheap socket adapters with onboard voltage regulator and multiplier jumpers which also work fine. The only downside is that they don't have a ZIF socket for the CPU...
Another difference between the board revisions is that some jumper headers are sometimes not populated. Instead the jumper pins are hardwired on the backside of the PCB. I tried to figure out their specific function but due to a lack of freetime I could not finish that until now.
By the way: because I was not able to find any suitable cache module I started designing a 256kb cache module on my own. Don't know if this will be working in the end and being worth the effort at all, but at least you can learn something whith such things 😉
Don't expect it to be ready too soon, as I can only work on it from time to time.
Regarding the video memory upgrade:
As far as I could figure it out it would require two 512kbyte/4MBit memory ICs in a very odd package.
This is called "zig-zag in-line package" oder "ZIP" (Amiga users may have heard of it before). Although the manual mentions it at some place I didn't realize how this upgrade should work for some time (mainly because I had never seen such a package in over 15 years of designing electronics and could not figure out how to connect any memory to that strange sockets).
Unfortunately these RAMs are very expensive today if you can find any at all and I don't know the exact type required. They are also very large blocking the PCI slots in the end, so I decided not to go after it anymore.
Quite a bit of information, but maybe it helps someone...
Regards
(P.S.: I am new to the forum so if I did something wrong regarding posting rules please give me advice and be patient. Thanks.)
RetroPC: K6-III+/400ATZ @6x83@1.7V / CT-5SIM / 2x 64M SDR / 40G HDD / RIVA TNT / V2 SLI / CT4520
ModernPC: Phenom II 910e @ 3GHz / ALiveDual-eSATA2 / 4x 2GB DDR-II / 512G SSD / 750G HDD / RX470