Hello,
I have found this old I/O card. As You can see it is missing two quartz oscillators. There is no name or producer on silkscreen. Do you recognize the symbol on the main chip or maybe you know simillar card?
Any help appreciated
The half moon with the small round object looks like Utron to me. (Or fake Utron)
If you feel lucky, you can try experimenting with something like 2MHz crystals. In the end, the FDC needs to get an 8MHz clock and the UART needs to get an 1.8432MHz clock. The UART could drive a crystal itself (no need for an external oscillator), but the layout of your PCB looks like the integrated custom SMD chip contains an oscillator and just drives a clock into the UART.
Also, I'd like to find out what these all jumpers do. So I guess I need to find that card name
Bernkastel7734 wrote on 2022-09-12, 18:50:Also, I'd like to find out what these all jumpers do. So I guess I need to find that card name
Jumpers on XT multi I/O-cards can often be determined using a continuity tester for the IRQ jumpers (they just go directly to the ISA IRQ lines) and trial & error for the base address jumpers. The BIOS is kind enough to detect serial and parallel ports on all typical addresses, so you can just use a tool like MSD to show the base addresses of the ports.
I tried a peek at http://www.uncreativelabs.de/th99/i/iio8_i.htm to find your card, but I didn't find any card with a battery depicted at the location your card has it. You might want to carefully rescan the images whether the battery is just omitted. The position of jumpers and ribbon cable connectors is more reliable on Total Hardware 99 than the presence of the battery holder, so maybe you get lucky finding that card. If not, I guess trial&error is the only way.
I have a card (still unidentified & untested) that I thought is identical to yours, but upon a closer look there are some differences. Anyway, here's a pic, you may use these values and check if you get the clocks earlier described by mkarcher.
FDC chips do not match between our boards, but I've checked the datasheets and both require 8MHz.
quicknick wrote on 2022-09-12, 22:30:I have a card (still unidentified & untested) that I thought is identical to yours, but upon a closer look there are some differences. Anyway, here's a pic, you may use these values and check if you get the clocks earlier described by mkarcher.
FDC chips do not match between our boards, but I've checked the datasheets and both require 8MHz.
So it seems the 24MHz crystal is three times the FDC clock and the 18.432MHz crystal is 10 times the serial port clocks. Those are both very common crystals. Chances are high that the card of the OP requires the same crystals. Swapping them around results in the serial port running too fast, i.e. being incompatible with any serial device because the baud rates don't match, but should not create immediate damage, even though the clock is higher than expected. At the same time, the floppy would run at a lower data rate, being incompatible with any floppy written by different computers and being unable to format floppies, because the revolution of the drive is over before all 9 sectors have been formatted. I thus recommend to give it a go with those two crystal values, try a mouse, and if it fails (or if the POST reports a serial port error) swap the crystals and try again.
