reid@DECWRL.DEC.COM (Brian Reid) (11/19/86)
I have asked people who are in a position to know the story about the LW+ upgrades, and they all say the same thing. I therefore believe it is probably true. In the LaserWriter controller board there are a lot of ROM chips. These ROM chips were manufactured for Apple by a certain company in Silicon Valley. The ROM chips do not meet the required electrical specification. In particular, some of them do not have enough output power capacity to drive the circuits that they are supposed to be able to drive. Hardware types call this "fanout". Evidently Apple did not test the ROM chips carefully enough before they put them into the upgrade kits, and as a result many are marginal. From sources at the unnamed semiconductor company, I have heard that Apple and that manufacturer have hammered out the details of the re-work agreement, and that new ROM chips have been manufactured, and that all upgrade kits manufactured after a certain date have those new chips installed, and everything is fine. I was also told by a less-reliable source (a student who had worked there) that the masks used to make the second round of ROMs were identical to the masks used for the first round, which means that any known bugs (if any) were not fixed before making the new ROMs. All of this is supposedly several months old, and I am surprised to hear that a recently-purchased upgrade didn't work. I just ordered an upgrade for my own LaserWriter, figuring that it was safe now.
farber@HUEY.UDEL.EDU (Dave Farber) (12/01/86)
Gents I know this is old BUT. Can someone reship to me the cable connection and software (postscript) that changes the LW+ to DTR mode of communications with a IBM PC. Dave