• Leaky Ni-Cd clock battery

The Ni-Cd battery may be leaking, risking damage to PCB layers & nearby components. Promptly remove the battery & clean corrosion/alkaline salts from the board. Use white vinegar to dissolve salts, but exercise caution as vinegar can corrode exposed metals. A thorough examination & repair may be needed. Replace battery with guide: https://github.com/wiretap-retro/Not-A-Varta

Jumpers: W1 A PREN ON = Normal floppy precompensation. (Default) OFF = Alternate floppy percompensation

W1 B DRVTYPE ON = Drive is dual speed 5.25" High Density drive. Spindle runs at 360rpm for 500kbit HD mode and runs at 300rpm for double density 250kbit mode. OFF = Single speed 5.25" High Density Drive. Spindle always runs at 360rpm, so data rate is 300kbit/sec double density and 500kbit/sec high density (default)

W2: ON = 0 wait state (default) OFF = 1 wait state forced

W3: 1-2, 2,3 on = 256K or 1M SIMMS 2-3 on = 4M SIMMs (16mb MAX)

SW1: 1 - NiCD battery connection. Closed = battery connected. Open = battern not connected. Set to open if you are using external battery. 2 - CMOS erase? Closer = battery power goes to oscillator (for time) and chipset for NVRAM. Open = battery power is not routed to chipset. 3 - ? 4 - ?

Notes:

The minimum standby voltage of the chipset is 3.0V (as per datasheet) so a CR2032 likely won't work in place of original NiCD battery. Replace with a 6V dual CR2032 pack connected to pin header.

82C711 multi-IO chip is entirely software controlled. The original C&T BIOS for this board cannot control this chip, meaning you are not able to disable onboard floppy and IDE and they are enabled at all times. The AMI BIOS has necessary options to turn off any of the IO ports so you can use an external ISA card.