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Old 15 April 2019, 15:50   #1
Changis
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Is my Amiga Cursed? ALICE dying? Bad RAM?

so, having had 2 bad amiga boards, and not enough knowledge (yet) to fix them properly, i managed to trade some stuff for a new amiga1200 mainboard.
my first issue was the keyboard not working properly, this turned out to be two lifted chips from the keyboard chip (from a previously removed external kb hack)
i managed to push them back with my soldering iron and got everything working seemingly fine again.

I also have a blizzard 1220 for expanded ram and faster cpu, which i ordered a ADD4 ram expansion for.
expansion arrived, and i plugged onto the 1220, but the system still only reports 4mb expanded memory. the ADD4 board has a jumper, but still only reports 4mb with jumper on or off (i am not using pcmcia slot at all)

I tried starting some WHDload games, but got a memory error, however regular workbench with apps worked fine.
then after a little while of testing, it started restarting and keyboard became unresponsive after a while. (ctrl-A-A still works, as do capslock light)
opening a text editor shows random keystrokes (seems to be from numlock area)
i unplug the keyboard (i have a onboard keyboard app in workbench if i need keypresses) and notice i get the same issue. tapping/pressing on the CIA-A or Keyboard chip showed nothing. though the issue only starts after a while, so i start checking the chips, and find that ALICE is getting very hot just from workbench idle.. i find a fitting heatsink from and old motherboard (northbridge heatsink as perfect size) and put it on with some noctua ceramic thermal paste, and load some system diagnostics to a CF card to diagnose the amiga. (my floppy doesn't work properly, and i don't have any disks available (but winuae and a cardreader works just as good)
this issue occurs with or without 1220 expansion (with or without ADD4 attached)

starting up amiga test kit, i only still get 4 mb expanded ram showing, even when ignoring kickstarts, however ram tests seems to be working without fail, however, the amiga still presses keys after a while (with heatsink, maybe 5-10 minutes just idling in amiga test kit's keyboard tester) this last time showing keystroke "ff" every third second or so.

Alice still gets very hot no matter what i try.

Long story short;
most likely ALICE chip overheats and creates issues/restarts
also ADD4 expansion does not supply 4mb extra ram (not sure if ADDfor or 1220 or ALICE is to blame for this, or something else entirely)


i've tried:
*two different card reader harddrives (SD and CF) - both work, no change
*with 1220 and add4 - no change (only reports 4mb instead of 8)
*with 1220 without add4 - no change
*without 1220 - no change
*without keyboard - no change
*Had priest perform extensive exorcism
*combinations of with/without keyboard/expansion
*with heatsink on Alice: - no change, but takes longer for issues to arise

is my ALICE chip dying? all the caps look fine, and seem to be changed recently, however i do have an extra set of caps from amigakit i could use to replace them, but i don't want to do that before i've exhausted other less "intrusive" solutions (if there are) or am i looking at a possible alice chip replacement?

i swear, i'm starting to believe that i'm somehow cursed to not have an opreational amiga, if i can't get this fixed, i might just sell off all my amiga stuff and use winuae instead

Last edited by Changis; 15 April 2019 at 15:55. Reason: added issues to title for easy identification
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Old 16 April 2019, 07:56   #2
modrobert
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I'm assuming you have the A1200 schematics.

Did you try to measure voltage pins on Alice using a multimeter?

Might be a good idea to check other voltage points as well, since Alice gets hot, maybe there's a short somewhere. If so you should be able to measure significantly lower voltages on the power rails.
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Old 16 April 2019, 09:18   #3
Changis
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Yes, i have schematics and amigapcb handy, ill go over the chip when i get home and can get out my multimeter.

After a quick glance yesterday, i could not see any obvious cracks or similar on the ALICE chip, but i might go over it with the soldering iron or hot air station if nothing else works (worst case, i have two more a1200 boards i could steal chips from)

I have attached a "screenshot" of what the amiga thinks the keyboard is doing (note, this is as stock as possible, only cf card harddrive and a serial to usb mouse adapter (shouldn't affect anything)
This is from just after about 2-3 minutes of on-time, not being taxed more than loading the diag software / workbench.


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I also read somewhere that it might be the kickstart? I have several kickstarts available to test with (3.0, 3.1, 3.x) but i doubt this is the issue?
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Old 16 April 2019, 11:40   #4
Jope
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The problem is in the CIA or the keyboard MCU, I'm sure.
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