These are 300-DPI scans of the TRAN Ampli-Bus PCB.

The Ampli-Bus was plugged into the Oric expansion connector and provided
three buffered expansion slots. The Jasmin floppy disc controller was
supposed to be plugged into the last connector.

The sanded-off chips are three ordinary TTL buffers (74LS244) and one
CMOS inverter (4069, if I recall correctly). But you don't have to trust
my foggy memories : the schematic was published in one of the later
issues of Théoric.

I'm fairly sure that it's me who cut the two traces (pins 33 and 34 on
the last connector), although I can't recall why I did. Probably
something to do with a ground loop. The blue wire on pin 3 of the last
connector is also of my doing. The switch was desoldered to facilitate
the scanning. When in the "+" position, an extra amount of conditioning
was applied to the phi2 signal.

-- AYM 2004-07-19

        876  2004-07-18  README
    118_847  2004-07-18  amplibus-comp.jpg
    143_879  2004-07-18  amplibus-cop1.jpg
    127_971  2004-07-18  amplibus-cop2.jpg