Hi all,
I’m working on a IIcx board repair and need to know if I should be seeing any activity on the NuBus address and data lines when no cards are plugged in.
There’s no activity on any of the pins. Just stuck high or low.
When I power the board on or hit reset all I get is a sad Mac chime.
If I plug in any of my cards (except for one) then I get no chime at all. Just a clicking sound and all I see on the cards is a clock signal. Except for a radius video card. I get a chime on that one but same thing only a clock on the card. The other card is an Apple Macintosh ii video card.
I’ve also noticed that with an OEM power supply when I push the soft power button it turns on and then back off immediately. If I hold it down it just cycles trying to shut off and no chime. I’m using an atx power supply on the bench instead and that powers the board up fine and I see activity everywhere except NuBus and I get that sad mac chime only. So wondering if maybe something power related as well. I’m pretty sure it’s a good power supply but not positive.
Not sure where to go next. But I’d really like to know what I should expect to see on that Nubus if the there’s no cards on it.
Thanks!
I’m working on a IIcx board repair and need to know if I should be seeing any activity on the NuBus address and data lines when no cards are plugged in.
There’s no activity on any of the pins. Just stuck high or low.
When I power the board on or hit reset all I get is a sad Mac chime.
If I plug in any of my cards (except for one) then I get no chime at all. Just a clicking sound and all I see on the cards is a clock signal. Except for a radius video card. I get a chime on that one but same thing only a clock on the card. The other card is an Apple Macintosh ii video card.
I’ve also noticed that with an OEM power supply when I push the soft power button it turns on and then back off immediately. If I hold it down it just cycles trying to shut off and no chime. I’m using an atx power supply on the bench instead and that powers the board up fine and I see activity everywhere except NuBus and I get that sad mac chime only. So wondering if maybe something power related as well. I’m pretty sure it’s a good power supply but not positive.
Not sure where to go next. But I’d really like to know what I should expect to see on that Nubus if the there’s no cards on it.
Thanks!