Re: 192 bytes free

From: Ruud Baltissen (
Date: 1999-03-18 22:10:13

Hallo Bill,

> Yes, 74LS257, not 74LS237
> The fact that the address count always stops at 192 (128+64) suggests
> that address bits 6 and 7 on the driver chip are defective (shorted
> together).  The chip at U25 drives both lines and the physical location of
> the drivers are located adjacent to each other on the chip.  This a
> typical failure of that kind of chip.
> The 74LS258 controlls refresh.  Failur of this usually gives a slightly
> different address each time.
> Bill

Thanks for the info. Makes realy sense.

Groetjes, Ruud

This message was sent through the cbm-hackers mailing list.
To unsubscribe: echo unsubscribe | mail

Archive generated by hypermail 2.1.1.