FINEBERG@WUMS2.WUSTL.EDU (Charlie Fineberg) (05/31/91)
Well I know that all of you are probably dying to hear about what I have done to attempt to fix my 2500/30 and I just can't disappoint you. To recap, this was the problem. My 2000 w/A2630 + 4M (the last two socketed yeah!) with 2 floppies and no hard disk (long story...) was merrily playing Lords of the Rising Sun last Saturday afternoon. When suddenly the pointer started adapting to mouse movements more and more slowly. The entire machine hung up (with one of the nice images from the game on the screen). It wouldn't respond to a cold reboot or any mouse/key/disk change. When I power cycled I got three quick flashes of the power LED and then Dk Grey, Lt. Grey and nothing. Still nothing to this very moment. Well what have you done between then and now? After all you consider yourself a college educated digital engineer and have been fixing DEC bus based systems (Q and UNI) for over half a decade. Why isn't it working yet? Well a friend of mine has an A2000 which is not responding to horizontal mouse movements but is otherwise working. He let me swap chips to find out both what is wrong with his system and with mine. Let me list what we swapped from one system to the other without changing the behaviour of either machine. (What is socketed on our mother boards?) BUSTER DENISE PAULA 68000 ROM I had a fun evening. Anyway, I didn't have the equipment or patience to swap Agnus (we both have 512K FANG). Does this mean that the offender must be Agnus on my board? (And yes I realize that U202 is probably the culprit for his mouse problems). And thanks to all those who told me to reseat the chips. I should have done that before I complained net wide, but it motivated me to be rigorous. I actually thoroughly cleaned the board too. Any help from any quarter gladly accepted! Charlie -- Charlie Fineberg Biochemistry Dept., Wash. U. Sch. of Medicine (WUMS) Box 8231, 4566 Scott Ave. BITNET: FINEBERG@WUMS St. Louis, MO 63110 internet: fineberg@wums2.wustl.edu
FINEBERG@WUMS2.WUSTL.EDU (Charlie Fineberg) (05/31/91)
Mark Gooderum was kind enough to help me specify my plight more directly... >> Lt. Grey and nothing. Still nothing to this very moment. > >Hmmm. > >> yet? Well a friend of mine has an A2000 which is not responding to >> horizontal mouse movements but is otherwise working. > >Did he check that it is ideed the machine, and not just the mouse, and >whether it is one or both ports? (You can get Intuition to switch >ports 0 and 1 with a left-Amiga-P). I didn't know about left-Amiga-P but I did know about setmouse2 and used it. It worked correctly. But many games (and my accelerator boards rom) don't recognize the right port... >> He let me swap chips >> to find out both what is wrong with his system and with mine. Let me list >> what we swapped from one system to the other without changing the behaviour >> of either machine. (What is socketed on our mother boards?) >> BUSTER >> DENISE >> PAULA >> 68000 >> ROM > >Of course the Mouse X/Y registers are on Paula. However, the ^^^^^ The way I read the apendices of _Introduction_to_the_Amiga_2000_ (the book that came with my 2000), it says that Paula does all of the A/D and D/A. So it does the audio channels the analog joystick channels and some disk control. Denise does the mouse ports. The signals are M0H, M1H, M0V and M1V. But since I was being thorough... >quadrature pulses go through some multiplexors before they get to >Paula (I think). You didn't mention the CIAs. They don't deal with >the X/Y but they do deal with the mouse buttons and the system time >clocks. My 1000 had similar problems and it turned out to be one of >the CIAs. Is that the mouse problem or the system hangup problem. The mouse quadrature signals all go through U202 which is a 74ls157. I think that is just a mux which is toggled (indirectly) by left_Amiga-P. >> have 512K FANG). Does this mean that the offender must be Agnus on my >> board? > >Well, if you system is totally hosed and refuses to boot, Agnus could >indeed be the problem. I wouldn't try swapping w/o a proper PLCC >extractor though. Agnus can take it, but the sockets tend to be fragile. Yeah, I'm hoping I can find a GAC (Gateway Amiga Club) member who has made the upgrade already and will let me borrow their old Agnus and the puller... >You also of course removed all peripheral boards, (inc. 2630) to >elminate them as culprits? Oops. I should have mentioned that right off. Yes, my current test is with power supply and monitor attached. Nothing else. I can do more tests per minute that way. Has anyone had their system behave the way mine has and known that it is independent of all of those chips I swapped? >Bitnet: MARKV@UKANVAX \/\/ / | | | | |__| / \ possible... >Internet: markv@kuhub.cc.ukans.edu And Mark, hurry back to the net. Your ability to eloquently answer questions posed (especially to i-amiga) has made it easy for me to get some work done. "I don't have to answer that one, Mark will!" Charlie fineberg@wums2.wustl.edu, fineberg@wums2.bitnet
dvlrab@cs.umu.se (Roger Abrahamsson) (05/31/91)
Well, it sounds almost like the problem I had a while ago on my A2000, and it turned out to be one of the CIA's. The system just hung up sometimes, some programs just crashed and the DTR to the modem refused to work.. When I swapped CIA's the keyboard went away and the caps-lock led flickered just fine.. Just try and swap the two CIA's and see the effect, I't might not be those who are faulty, but better make sure. They seem to break very easily and isn't that expensive, (compared to the AGNUS). /Roger
monty@sagpd1 (05/31/91)
Have you checked all of the power supply voltages? Sometimes a switcher
will "brown out" and leave all or some voltages low. This can cause many
wierd problems.
Monty SaineFINEBERG@WUMS2.WUSTL.EDU (Charlie Fineberg) (06/04/91)
Yet another update on my still sick 2500/30... Mark Gooderum (he just moved so I don't have a valid address) and dvlrab@cs.umu.se (Roger Abrahamsson) both suggested that the CIAs caused a similar problem on their machines. So I swapped them and no go. Exact same symptoms. And this is not an occasional hang with no response it is getting stuck on the (I think, now that I have stared at a vanilla 2000's startup sequence for a while) the white screen that I am stuck on. It seems actually to get through an initial flicker and then a dark grey and light grey before hanging on the white screen. No other response, with or without the A2630 card in (well the power light only changes intensity once with the 2630 out...) monty@sagpd1.UUCP (Monty Saine) wrote that I should check the power levels. What is the correct way to do this? In the past I've used one of the free connectors off of the power supply while the main connector was connected to the mother board. Is this adequate? And now for the really frustrating one. I thought that I had debugged my friends machine. So I desoldered and soldered on a new U202 74LS157 that multiplexes the signals from denise to the mouse. And when I powered back on it seemed to be working (not that I hadn't gotten that response for a few seconds from the old chip too) but then horizontal movement disappeared again. To recap: On both machines the problem is not Denise Paula Gary Buster Rom 68000 because I swapped them from one machine to the other and both machines behave the same as they did before. I have tried swapping the two CIAs on my 2000 and still have had no luck. I am still hunting and very frustrated. Anyone want to sell me an old Agnus and chip puller? Anyone want two A2000's cheap? Aaargh. I am a frustrated cowpoke people. Charlie -- Thats fineberg@wums2.bitnet or fineberg@wums2.wustl.edu in dog years! -- Charlie Fineberg Biochemistry Dept., Wash. U. Sch. of Medicine (WUMS) Box 8231, 4566 Scott Ave. BITNET: FINEBERG@WUMS St. Louis, MO 63110 internet: fineberg@wums2.wustl.edu "The younger Mr. Popplewick is not permitted to expect anybody" - Mr. Popplewick
peterk@cbmger.UUCP (Peter Kittel GERMANY) (06/04/91)
In article <9106040619.AA27553@wugate.wustl.edu> FINEBERG@WUMS2.WUSTL.EDU (Charlie Fineberg) writes: >Yet another update on my still sick 2500/30... Well, I fear this won't apply to your case, but it may serve as a lesson for me and some others. Only recently we came across a hardware error that was thought to have disappeared for years but now happened again: We had an A2000 where no AT Bridgeboard wanted to work at all. All the bridgeboards worked well in other Amigas, but not in this one. (Similar things might happen to cards in the CPU slot, but then your error should disappear when you take out the A2630.) Finally we found that this was due to a very old version of the casing, more precisely the bottom part of it. There is one more place (like a nut, I don't know the precise English word) in the bottom to receive a screw to fasten the mainboard on the bottom. Now in newer boards there is no hole in this place, but normal traces. If you now insert a card, the board is slightly bent, and the traces touch this post (metal) and get shorted. Luckily this doesn't damage anything, only keeps the bus lines there from working. - So the general hint: Just look under your mainboard and search for posts that don't align with a screw. If you find any, use insulating tape to "debug" it. -- Best regards, Dr. Peter Kittel // E-Mail to \\ Only my personal opinions... Commodore Frankfurt, Germany \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk
daveh@cbmvax.commodore.com (Dave Haynie) (06/05/91)
In article <9106040619.AA27553@wugate.wustl.edu> FINEBERG@WUMS2.WUSTL.EDU (Charlie Fineberg) writes: > To recap: On both machines the problem is not > Denise > Paula > Gary > Buster > Rom > 68000 >because I swapped them from one machine to the other and both machines >behave the same as they did before. I have tried swapping the two CIAs on >my 2000 and still have had no luck. I am still hunting and very >frustrated. Anyone want to sell me an old Agnus and chip puller? >Anyone want two A2000's cheap? Aaargh. Chip swapping, while the easier way to track down problems, is also about the worst way to go about it, unless you have a very obvious indication that a particular chip is bad. If you don't, you'll only be lucky if you find the problem. Obviously, not everyone's a computer designer (though, of course, our lab and production technicians, along with an unknown number of field service people, undoubtedly debug these things a zillion times faster than the folks who built them, since they have practice and know what goes wrong, where all we know is how the thing works) with access to 'scopes and analyzers. First thing you do is check out anything that you might have changed in the system. Did you plug in a new peripheral? Hook up that printer last night with the power on? Recently add plug-in memory? Change Agnus chips? Have any thunderstorms or power surges? Computers do sometimes "just fail", if a marginal part finally makes it under the margin for good. But most of the time, something causes the problem. Being that volt meters are common, though, I always recommend that early on, you check the computer's voltage, at a remote point on the motherboard or, better yet, an expansion card if you have one. The voltage should read just about exactly 5V, with everything turned on. A computer could work just dandy for years, just on the edge of the margin, then get flakey as soon as one more little thing is attached. Zapping your system somehow is annoying, since it can get many different parts of the system, but some are more commonly clobbered than others. If you mis-plug something in a floppy or parallel port, you can damage either CIA chip. If you mis-plug the video port, you might zap a small decoupling resistor that links Denise to the main voltage supply. I've even heard of someone zapping the protection diode on the "+12V_User" supply, which is had at the video or serial ports. It's also technically possible to destroy Agnus (via the video port) or Paula (via the serial or mouse ports) from the outside, though this happens less often than a zap of an 8520, if for no other reason in that there are about 10 CIA pins for every one Agnus/Paula pin at these ports, so the CIAs are a bigger target. After that, remove EVERYTHING that's hooked to the system except for the monitor, keyboard, and floppy. If it still fails, you can attack the problem methodically. Of course, it's much better with a 'scope, then you can follow things very closely. You check to make sure you have all the proper clocks running. You check to make sure the OVL pin is going low out of the 8520 (this can be checked with a logic probe, even). Check the TICK signal going into the CIA, that can prevent the system from coming up. Check the RESET* signal and make sure its high. Check for activity of some kind on the 68000's AS* and DTACK* lines. Check the ROM chip select for activity. And finally, even experienced hackers can't solve every possible problem. Unless you know the system inside and out, and have the equipment to trace though the whole operation, you may not be able to determine what has gone wrong. At some point, you need your computer back in working order. You may have to take it to a service center, plain and simple. >Charlie Fineberg Biochemistry Dept., Wash. U. Sch. of Medicine (WUMS) -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "This is my mistake. Let me make it good." -R.E.M.