@tbtorro When an A4000D Rev B have an external drive connected the internal drive stops working. Tries to boot on startup, but gives up after 3 times trying to read the disk. When the external drive is disconnected the internal FDD works as expected including boot. Also if the internal drive disconnected (by cable) the […]
Category: Amiga
A4000 Rev B stuck at early boot (grey screen)
Newly built A4000 motherboard. Tested all resets, supply voltages, and there was video out. DiagROMs would also not initialize, indicating very early fault during boot (during reset routine). _OVL signal on CIA B (U350) would go to high at hw. reset, but would not return to low indicating the CPU didn’t write back to CIA […]
HDD Led always bright using some SD/CF Adapters
Some SD/CF Adapters makes the HDD led always bright and you can see a flight flicker when the disk is loading. This can easy be fixed by replacing the PNP Transistor Q631 with a PNP Transistor with an extra Resistor just like the PDTA123ET Transistor. now HDD light will behave normal.
Amiga 1200 video DAC information
Some information about the video DACs If the Amiga rev 1 board uses ( or will be ): ADV101 D215, C215, R215 must be placed on the board. VP101 D215, C215, R215 must be removed from the board. On the lower pins of D233a a 1uF 0805 capacitor must be placed. If you […]
Amiga – What are those board jump wires ?
Amiga 1200 CCK clock signal – Alice to Budgie The technical reason is that the CCK clock signal coming out of Alice is not clean enough to drive the input on Budgie. It was cheaper for Commodore to clean the signal up using a buffer chip in stead of fixing the Alice chip itself. They […]