kevin@kosman.UUCP (Kevin O'Gorman) (03/28/91)
I got impatient about some info on the HD2 upgrade, and tried running as just a P5.1 upgrade (replaced the PAL into the socket). This machine now appears pretty dead. The symptom is what I have come to call the "rectangular spiderweb" on the screen, no disk activity, no marching blocks, no evidence of CPU activity at all. The screen has a repetetive pattern probably caused by alternating 32-bit words of all 1's and all 0's -- fine rectangular tracery. Either this is the pattern that the video ram defaults to, or is caused by an early step in the boot roms and the fact that a video raster is an odd number of 32-bit words. The green LED is on solid, the others off. Well, I probably did it to myself, but I could sure use some help figuring out just exactly what I did.... I have tried looking at the power supply, which was the culprit the last time I saw this pattern. I had -12.03, +5.25 and +12.03. I have read that 12.40 is a bit more like it and tried tweaking. On two different supplies I can tweak +12 and +5, but -12 is rock solid no matter what I do to the pot. Is that pot for real? Should I be able to adjust -12? Anyway, this is not solving my problem. Please, anyone have advice for debugging a HD2 upgrade when your tools are a soldering station and a digital multimeter and a couple of space power supplies? Fortunately, this machine is my (very) old 7300 Attilla, who has been through the wars since I bought him in April of '85 (yeah, just two weeks after the product announcement) with 512K and a 10-MB disk (what good was that, you ask? I used it as a word processor (to make money), and to teach me UNIX and C). I still have Ghengis, a fire-sale 3b1, which I will upgrade if I ever get back my confidence. fire-sale 3b1. -- Kevin O'Gorman ( kevin@kosman.UUCP, kevin%kosman.uucp@nrc.com ) voice: 805-984-8042 Vital Computer Systems, 5115 Beachcomber, Oxnard, CA 93035 Non-Disclaimer: my boss is me, and he stands behind everything I say.