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Sun Ultra 5 RAM Upgrade Issue

DECtechGuy

Experienced Member
Joined
Jun 22, 2017
Messages
159
Location
Florida
So I have a Sun Ultra 5 that has 256MB of RAM in it and I got an identical set of 128MB DIMMs to push it up to 512MB. Only to find that the opening header still says 256MB. Swapped the DIMM pairs and it still says the same, so they all work, just not together it seems. I have OpenBoot 3.25 on it and would like to upgrade since I think that might be the problem? Not sure, but I can't find any newer copies of the PROM online yet. Unless someone here has one, I'd appreciate a copy. :p

Suggestions?
 

DECtechGuy

Experienced Member
Joined
Jun 22, 2017
Messages
159
Location
Florida
Yup managed to find that and an FTP server with that zip on it. Now just a matter of upgrading.

However, and I just tried this today, my Ultra 5 won't do anything if I only install DIMMs in Bank 0(sockets 1 and 2) and leave Bank 1(sockets 3 and 4) totally empty. Now i'm wondering if bank 0 is dead...

Looks like I need to get a DB25 serial cable and use TIP to get a definitive answer.
 

DECtechGuy

Experienced Member
Joined
Jun 22, 2017
Messages
159
Location
Florida
Updated OpenBoot, no change.

While in the process of updating it, I managed to get more output from the initial post and the banks are shown as just being straight up empty with no errors. SunVTS passes. Something is wack...
 

Jenz

Experienced Member
Joined
Mar 14, 2019
Messages
85
While in the process of updating it, I managed to get more output from the initial post and the banks are shown as just being straight up empty with no errors.

Can you provide some details of the memory modules? It may be imagination, but sometimes reset-all seems to help ...
 

DECtechGuy

Experienced Member
Joined
Jun 22, 2017
Messages
159
Location
Florida
reset-all didn't help, unfortunately.

As for the modules, when I bought them I had just searched for the same part number that I saw on the RAM that came with the Ultra 5, which were 128MB, 50ns, EDO, ECC ram. So I've got dimms that are completely identical, even with the same Micron labels.

These dimms all work, since i've swapped them in and out of the bank that works.
 

Jenz

Experienced Member
Joined
Mar 14, 2019
Messages
85
4 x KMM372F1680CK-5 from Samsung here, low profile to save the unused floppy drive ... ;) I vaguely remember some issues with Micron ...
 

DECtechGuy

Experienced Member
Joined
Jun 22, 2017
Messages
159
Location
Florida
There was something in the documentation I have about using Micron's with a certain openboot versions and high MHz processors, but that should have been fixed with the newer version. Probably will try out that variant of ram and see where I end up.
 

mdog69

Member
Joined
Sep 8, 2019
Messages
11
Location
West Midlands, UK
Some random things:
1) Check the OBP environment variable "selftest-#megs". ISTR having issues with a Sun box* reporting incorrect RAM, and I had the selftest figure set incorrectly. (* can't remember if it was an IPX, SS5 or a U5 I was playing with)
2) The Micron memory issue: https://shrubbery.net/~heas/sun-feh-2_1/collections/fins/I0598-1.html
3) If you don't already have it, the U5 service manual can be found at https://docs.oracle.com/cd/E19127-01/ultra5.ws/805-7763-12/805-7763-12.pdf Appendix C may be useful if you are thinking about getting your soldering iron out.
 
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