dirks@kaa.eng.ohio-state.edu (William R.Dirks) (10/26/89)
I am having some difficulty getting my LUCAS project to work. When I power up or reset the power light flashes five times, then I get a dark grey screen. And that's it. No boot song, Kickstart hand, etc. Everything I can find in the docs about a board that gets part way through boot-up says try different logic families for U9, and/or different clock speeds. I have tried the following parts for U9 at both 16 and 20 MHz: 7474 'ALS74 (TI) 'AS74 (National) 'F74 (Fairchild) 'F74 (Motorola) 'LS74 (Signetics) 'S74 (TI) In every case exactly the same thing happens, which leads me to believe it's something else. I have examined the board very closely for soldering mistakes and other defects many times. I found nothing suspicious. The board mates with the motherboard socket firmly and comfortably. Amy works perfectly with her 68000 reinstalled. When I tested the LUCAS board I had all peripherals disconnected except for monitor, mouse and keyboard. I have grounded the PALs on the Kickstart daughterboard. I have pins 1 of J1 and J2 connected together. I have not performed any other hacks on LUCAS. I am hoping someone out there has some knowledge of similar problems with LUCAS, or with what is happening at that phase of boot-up which would help me track down this problem. The only debugging tools I have are a multimeter and a BSEE degree. Any help/insight is greatly appreciated. -=- Bill Dirks dirks@kaa.eng.ohio-state.edu
douglee@becker.UUCP (Doug Lee) (11/02/89)
In article <3326@quanta.eng.ohio-state.edu> dirks@kaa.eng.ohio-state.edu (William R.Dirks) writes: >I am having some difficulty getting my LUCAS project to work. When I >I have tried the following parts for U9 at >both 16 and 20 MHz: stuff deleted to keep rn happy > 'LS74 (Signetics) Try using National 74LS74's. Also try as many brands of LS parts as you can find. Check the tolerances of R1 and R8 as they are critical. The brand of clock generator is also relevant. I find that KDS brand works better than Fox brand. There is also the possibility of a bad CPU. Someone brought me a board to debug which actually ran CPU cycles when viewed on a scope, but wouldn't boot due to a dead 68020. -- Doug Lee douglee@becker 416-461-5357
hamilton@intersil.uucp (Fred Hamilton) (11/03/89)
In article <3326@quanta.eng.ohio-state.edu> dirks@kaa.eng.ohio-state.edu (William R.Dirks) writes: >I am having some difficulty getting my LUCAS project to work. When I >I have tried the following parts for U9 at >both 16 and 20 MHz: > < rest deleted > Just to make things more complicated, I have found that experimenting with U8 (if I remember the number correctly, it's definitely the one in the lower left corner) made mine (and a friend's) work MUCH more reliably. I think I ended up with an LS and he used an ALS. -- Fred Hamilton Any views, comments, or ideas expressed here Harris Semiconductor are entirely my own. Even good ones. Santa Clara, CA