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having issue maxing ram in 486

oblivion

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Aug 28, 2010
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Apache Junction, AZ
i've been running 8MB of ram via 8 1mb sticks for some time now and have been wanting to upgrade to my MB max ram of 32mb for some time now. i recently found affordable 4mb sticks here
http://www.datamemorysystems.com/_memory-information/DM13_013.asp

so i bought 4 sticks. once they arrived i plaaced them in the pc, booted up fine and detected 16mb of ram. happy that this worked i orded anouther 4 sticks and they arrived today. after placeing all the ram i got a few beeps on startup, it detects the full 32mb and then.

"CMOS memory size mismatch" also when you hit F1 to continue i get

on board parity error
addr (hex) = 0000:0002)
system halted

i tried to enter the bios by hitting delete on bootup but it won't enter bios settings and i get a keyboard error message, i tried 2 diffrent keyboards with the same effect.

so thinking it was an issue with the extra ram i removed 16mb back down to the working 16 i had but i had the same error. the only way i can get it to run now is going back to the 8mb of ram useing my 8x1mb sticks. ive tried reseating the ram several times to no effect. im sure when i origionally switched over to 16mb via 4x4mb sticks it worked for me so i don't know why even that config won't now. i even tried pulling the battery to reset the cmos but nothing. any help? i would love to get my 32mb in this thing.

my MB is
amibios 1992 american megatrends inc
UM486V AIO V2.0 03-25-93
 
Usually, the memory size mismatch is normal the first time you boot it up. On subsequent power-ups, it remembers the amount of memory you had last time.

The parity errors suggest to me that one of your sticks has a problem. I assume these are 30-pin SIMMs, so you have to install them in sets of 4. That will make it harder to isolate the problem, but basically what you'll need to do is put 16 MB in, check for the problem, and if you find it, swap one stick out of the set at a time until you (hopefully) locate the bad one.
 
Weird question, but how shiny are the pins on the simm slots? Could just be dirty connections...

Also, try this to test the ram. Stick in 4 1mb simms, then 4 of the 4mb's on the last 4 slots. Run memtest, then repeat with other 4 sticks. Error you have given shows an error on simm slot #1 btw.

And finally, dont forget 30 pin simms came in both parity and non-parity flavors. Perhaps you ordered the mac/IBM compatible parity ram by mistake or vice versa? Please count the chips. All non-parity 30-pin SIMMs have an even number of chips; all parity 30-pin SIMMs have an odd number of chips. On a non parity board, you SHOULD (not always) be able to use both parity and non parity ram. You can not do the same mixing on a parity board.

Glad to see you use DMS btw! Great store! :thumbsup:
 
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Weird question, but how shiny are the pins on the simm slots? Could just be dirty connections...

Also, try this to test the ram. Stick in 4 1mb simms, then 4 of the 4mb's on the last 4 slots. Run memtest, then repeat with other 4 sticks. Error you have given shows an error on simm slot #1 btw.

And finally, dont forget 30 pin simms came in both parity and non-parity flavors. Perhaps you ordered the mac/IBM compatible parity ram by mistake or vice versa? Please count the chips. All non-parity 30-pin SIMMs have an even number of chips; all parity 30-pin SIMMs have an odd number of chips. On a non parity board, you SHOULD (not always) be able to use both parity and non parity ram. You can not do the same mixing on a parity board.

Glad to see you use DMS btw! Great store! :thumbsup:

hmmm, on the diagram/stats i found on my mb it mentioned in the ram section i need 4x4(9) chips so maybe that means i need sticks with 9 chips? the ones i'm useing have 8.

Does your CMOS battery hold a charge?

yhea, its only a year old battery
 
8 chip 30 pin SIMMs are used in Macs, the 9 chip (parity) is what old PCs need. Is there a setting in the BIOS for parity memory?
 
hmmm, on the diagram/stats i found on my mb it mentioned in the ram section i need 4x4(9) chips so maybe that means i need sticks with 9 chips? the ones i'm useing have 8.


LOL I knew it! Had a feeling it was a parity issue. Been there, done that, have the door prize... ;) The ram should at least be easy to find.

As for macs and parity ram, here's something I bet you didn't know. There were special versions of the Macintosh IIci that used parity 30-pin SIMMs!!! :shock:
As for your old ram, perhaps you can throw it up on here for sale/trade to someone with an old mac. Hate to see you loose money on a silly oversight.
 
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Disable the parity test in the BIOS and you can use non-parity SIMMs just fine.

Parity isn't at all useful on a PC, as all that happens when an error occurs is the PC crashes and shows an error message like the one the one you saw.
 
well i got impatient and ordered some 9 chip 30 pin ram that i hope will work. as for the ram i have i happen to have some old macs that could use it so its not a total loss. i'll post again when the ram arrives to give the update.
 
got 9 chip 4mb ram sticks today, worked like a charm. finally have my 486 dos rig decked out

DOS 6.22
intel 66mhtz 486 with heatsink/fan
CD-rom drive, 1.44MB 3 1/2 inch FDD, 1.2 MB 5 1/4 FDD
500MB HDD
32 MB ram
diamond speedster pro 1MB VLB video card
sound blaster 16 paired with a roland MT-32
HP flat screen CRT monitor
 
Nice! Glad to hear its all working great!

Time for you to do the sacred banana dance
banana125.gif
to please Zeus, the computer god! Also, don't forget to offer a sacrifice! :eek:nfire:
 
I had a long debate before, if it was Zeos or Zeus. At the end of the conversation we decided it was Zeus, since he was the god of thunder/electricity... LOL
 
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