todd@snowcat.umbc.edu (todd bernard) (06/30/89)
I just installed the 1 meg angus in my 2000. It comes up with a meg of
chip memory, but I've had some strange this start happening. My 2000 (Rev 4.4)
has an 8 up board with 4 megs and a hardframe with a 40 meg HD. With everything
in the system, I open up the clock and it's all screwed up for example the
second hand will leave orange splotches as it goes around the face. With
floppy disk accesses I will occasionally get read/write error requestors,
if I click on retry everthing is fine. Also with floppy disk accesses the screen
will flash.
So I thought it might be the expansion boards not getting along with Agnus.
I pulled them out and the machince seems to work like normal about have the
time. I was just wondering if there might be something with my mother board
rev and the new agnus.
Thanks
Todd
Todd Bernard Disclaimer: Anthing said here is not my
todd@umbc3.umbc.edu employer's opinion.
hull@hao.ucar.edu (Howard Hull) (07/03/89)
I finished the fatter Agnus upgrade on my Haynie4.4 Amiga 2000 motherboard this morning and it seems to run fine and dandy. As usual, the helpful suggestions of other netters saved the day. The winner is the guy who recommended removing the EMI shield and pressing the old FANG out of its socket through the two holes drilled in the bottom of the motherboard. Without that one, I would be still at it - I had it laying upside down on the floor with two allen drivers pressed in there and was almost able to do a hand stand on the thing before it would come out. It musta taken fifty or sixty pounds... For the rest of you who are contemplating this, I might as well add that on this one you are going to have Ami stripped down to zero undergarments before you finish, so you might as well set yourself up with a good system for keeping a large quantity of nuts and bolts separated and classified. Begin by disconnecting the keyboard and mouse and RS232/PAR stuff & AC. It is then necessary to remove all the added bus modules, the 2620 (if you have one), the 2300 genlock (or the Flickerfixer), and disconnect the disk & power LED. Then unplug the white nylon power supply connector (CN400 in the docs), remove the two middle power supply attachment screws, followed by the two rear ones. I found it helpful at this point to disconnect the disk drive power harness and to lift out the power supply and place it upside down in front of the machine. This gives better access to the floppy disk data connector (which is routed under the drive and power supply tray). Remove the two rear tray mounting screws (these are the lower ones that appear the same size as the power supply screws - they do not hold the power supply in place, so don't behave as though you thought they did - the dealer said to me "Don't drop the power supply on the mother board." You have to cut just one trace, not all of them). Now, while realizing that the tray is free floating at the back (so don't do anything fancy) remove the three front tray attachement screws. It should now be possible to lift the tray up and out, collect the power supply, and head off across the room with it all so you can put it down somewhere where you won't knock it off your bench or table or whatever. This is the best time to deal with the trace you need to cut, as everything is gone from the innards of the machine but the motherboard, and you have an unobstructed view of the top surface of the board. It is necessary to move one jumper (J101) by pulling off the mini-jump and moving it one position to the left (as seen from the front of the machine). The jumper is located near the right front corner of the power supply connector. This is EASY. Everything should have been like this. Now then, the trace that needs to be cut is a VERY SHORT almost invisible one that goes between the two pads that make up the location of jumper J500 (I say "jumper" advisedly, since the trace is there to make up for the fact that there were no 25 mil posts installed on the 4.4 motherboard to implement this jumper and it was in fact implemented on the CAD instead. I hope this teaches them a lesson!). [The installation notes say (concerning the Amiga 500 FFANG exchange exercise, anyway) that one must be careful of nearby traces that run parallel with or under the silkscreen markings as it is REALLY EASY TO GOUGE THESE while working with an Exacto knife and trying to constrain its motion so as to cut only the desired trace. I very definitely recommend that this operation be done with lots of light, or perhaps with the aid of one of those lamps that has a circleline fluorescent lamp with a magnifying glass in the center, even though there is much more room longitudinally than one would have between a group of ten mil traces running across the board together. This exercise is a good way to find out why it is that most of us are not brain surgeons. Another way to remove this trace with minimum risk would be to use a hand-held MotoTool with a ball-end bit. I have one at home (but forgot to bring it). When you're done with this you can relax and have a soda, but NOT BEFORE. You know, the caffeine, the shakes... As for beer, forget it. Now this is the point in time where it would be really nice to be able to read and follow the Commodore instructions - "NOTE: The correct IC Extractor Tool must be used when removing the original 8370 FAT AGNUS from the socket. The Extractor Tool is available from Commodore Parts. P/N 314874-01" and probably quicker than you'd ordinarily think. So maybe you want to put this whole thing aside before you find yourself engaged in the following adventure: (See note [1] below). Back to Ami, you can now remove the roughly one-dozen motherboard attachment screws - but keep in mind that two of them are booby trapped. The one that holds the end of the external disk drive D connector closest to the 8520 IC's and oppositely at the front, one of the ones on one of the front mouse port connectors are attached by blind nuts. When you turn these screws, they'll feel less positive than the rest - you needn't share the experience I went through in assertively removing them - just go on unscrewing the others until you can get a feel for what's still holding the board to the box. There is at least one screw that's quite a way in from the edge of the board, so don't just try to snatch it out of there after you have the outside screws taken out. The board can be removed by lifting it up at the front, and then pulling it up and forward to allow the D connectors and RCA jacks at the rear to disengage from their mounting holes. To remove the EMI shield you will need a thin-wall nut driver that fits the D Connector attachment hex studs - or you can depreciate your Amiga an extra amount for the benefit of the IRS by removing them with a small pair of long-nosed pliers (cringe). Suit yourself. It IS worth while to take them all out, as opposed to cheating by loosening the shield at the mouse connector edge only and hoping you can get at the FANG holes by lifting only one edge of the shield. You can do that if you want, but you will probably be much better off to just surrender to the electronic gods, remove the shield completely, put the board upside down on a smooth surface where you can generate some force in a fashion with some semblance of control. Two Allen hex drivers held together in one hand, one in each hole, should allow you to push out the old FANG - it will likely take a bunch of force, steadily and evenly applied. You might want to observe the orientation of the old chip chip before you do this though, as if you have bad luck you'll have to put it back the way it was... The new chip goes in with the notch you'll see in the center of one edge placed opposite the "1" silk screen marking on the motherboard. My old FANG did not have a notch in the center of any edge. However both it and the new FFANG had a ever so slightly cut away upper left hand corner (as seen from an orientation where the board "1" mark is top-center). This relief on the parts is matched with a similar counter-relief at the corner of the square socket. Now all you have to do is put it all back together just the same as you took it apart - should be DUCK SOUP. (Um, er, just how IS it that you make duck soup, and why does anyone think that it's easy? Ever try it with a wind-burned piano-wire tendoned chain-mail bellied transcontinental duck?) Only one thing to watch out for after you put this back together, and it's something that has been mentioned by another netter fairly recently. If you have BufMemType set to "4" or "5" for anything in your MountList, and you are doing this exercise on a 1 megabyte Amiga 2000, you won't have any type 4 (Fast) memory for AmigaDOS to put the buffers in when you come back up alive, so your Hard Disk (or perhaps your "Clock" executable? may not work). It would be best to edit your MountList to set the hard disk BufMemType to "0" (Any) or "1" (Public)? before you take your machine apart... But you will have more than 900K of Chip ram when you're done - Good Luck! Note [1]: "Perhaps the greatest adventures in life are attributable to poor planning." Howard Hull hull@hao.ucar.edu