Re: CBM 8280

From: Nicolas Welte (
Date: 2000-08-23 13:56:04

William Levak wrote:
> My sources say that the 2797 is not completely compatible with the 1797.
> The biggest difference seems to be that the 2797 does not support non-IBM
> modes.  There are also a few differences in the pinout.

The main difference that I found is the power supply, the 179x series needs
an extra 12V analog supply. But I didn't study the datasheets very

> If the drive LED that is constantly on, is actually a drive LED and not a
> power LED, then that drive may be defective.  Try disconnecting it.

I got some more info from him (but still not if the blinking is a special
pattern or not): There are three LEDs, two drive activity LEDs (upper and
lower drive) and the red/green power LED, so we have the same situation as
with the 8250. The power LED and the lower drive LED blink synchronously,
about once per second. I don't know if it is a symmetric blinking or not,
but I don't think it is a count followed by a pause. The upper drive LED is
always on most of the time, but sometimes it goes off after powering on the
drive. Still the blinking on the other LEDs stays the same. Disconnecting
both drives didn't change anything, because all LEDs are connected to the
controller board, he says.

> Can he read the command channel?

No, he says that hangs the computer.

He's now going to read out the ROMs and compare them to the copies
available on funet and/or Bo Zimmermans site. I'll keep you updated.

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