IBM

Unsupported DIMM detected is RS/6000 7024-E30

Is there any non obvious way to deal with F25 Unsupported DIMM detected on an RS/6000 7024-E30? The machine was disassembled and reassembled years ago, after what it wouldn't post - nothing could be seen on the LCD. Since it's big and I have to downsize my collection I decided today to try to revive it one last time. I reseated the CPU module, the DIMMs and launched it. It fails with "Unsupported DIMM", but these were the modules this machine came with and it ran with them (2 DIMMs, 64 MB each, in the first 2 slots). Any hints what could be wrong?
:PI: :Indigo: :Indigo: :Indigo: :Indy: :Indy: :Indigo2: :Indigo2IMP: :Octane: :Fuel: :540: Image
Have to ask: are you sure nothing's wrong with the DIMM or the socket?
smit happens.

:Fuel: bigred , 900MHz R16K, 4GB RAM, V12 DCD, 6.5.30
:Indy: indy , 150MHz R4400SC, 256MB RAM, XL24, 6.5.10
:Indigo2IMP: purplehaze , R10000, Solid IMPACT
probably posted from Image bruce , Quad 2.5GHz PowerPC 970MP, 16GB RAM, Mac OS X 10.4.11
plus IBM POWER6 p520 * Apple Network Server 500 * HP C8000 * BeBox * Solbourne S3000 * Commodore 128 * many more...
Well, I'm not sure, but there's no physical damage on the DIMMs or the sockets. It seems these are 5V DIMMs and I don't have another computer to test them. I've installed them in DIMM 0 and DIMM 1 - does the RS/6000 have any requirement on how to install the modules? Do I have to have installed both?
:PI: :Indigo: :Indigo: :Indigo: :Indy: :Indy: :Indigo2: :Indigo2IMP: :Octane: :Fuel: :540: Image
Yes, I'm pretty sure they have to be matched pairs.
smit happens.

:Fuel: bigred , 900MHz R16K, 4GB RAM, V12 DCD, 6.5.30
:Indy: indy , 150MHz R4400SC, 256MB RAM, XL24, 6.5.10
:Indigo2IMP: purplehaze , R10000, Solid IMPACT
probably posted from Image bruce , Quad 2.5GHz PowerPC 970MP, 16GB RAM, Mac OS X 10.4.11
plus IBM POWER6 p520 * Apple Network Server 500 * HP C8000 * BeBox * Solbourne S3000 * Commodore 128 * many more...