A3000D weird RAM behavior

[tiim]

Hello everyone,

I have a stock 25Mhz 030 A3000D. I have it populated with 12MB 80ns static column zip ram and 2MB chip ram, everything goes great.

I add the last 4MB of static column zips, unfortunately, these are 60ns and not 80ns, as I do not have 80's laying about.

In DiagROM everything is correct during memory scan, no bad blocks. 16MB fast RAM.

While attempting to boot WB3.1, my BlueSCSI won't work.

I tried a WB floppy, it failed to boot, I tried an old CU coverdisk, it worked, and showed 16MB in workbench. I tried my Gotek and it kept failing, back to coverdisk, it was hit or miss...

I remove the offensive faster RAM and it's happy.

Please share your experience here. I do find it odd that one bank of faster memory would cause a system to be so erratic, but it was sure easy to spot! I have not tried swapping the first 4MB bank with the 60ns RAM, as you know, inserting and removing zips never is "fun".

Thanks,

Tim

[pipper]

It’s possible that you got screwed with those 60ns static column rams and they are really FPM. Now that would mean you’re mixing static column and FPM. This can only work if you put the FPM ram into bank 0 first. This way, when the system boots up and performs to check if there’s FPM or SC in your system, it’ll configure Ramsey for FPM and everything is good.
Tdlr; try putting the new ram into the first banks and see if it makes a difference.

[tiim]

Hi pipper,

The chips are labeled and sold as static column, so following your advice, I added them to my first bank, and workbench boots off the HDD now. I will remove all chips except bank 1 and run a memory test on them to see what I get.

Thanks,

Tim

[patrik]

Bought some 60ns static column ones and if you looked closely, they had the surface sanded down so it was a bit coarse (compare to back side). Also the text was not straight on some of them. Needless to say, they were neither 60ns nor static column.

[tiim]

So These chips work in Bank 1, Sysinfo gives my machine a speed of 0.89 x a real A3000D so I am guessing I am actually in fast page mode?

UPDATE: I removed the "Toshiba TC51402AZ-60" ZIPs and placed my original 12MB in banks 1,2 and 3 and now SysInfo gives me a 1.00 speed compared to an A3000, so, these chips must be re-marked... and I bought from a world-class seller on eBay. I'll let them know.

Thanks for reading.

Tim

[giantclam]

I bought from a world-class seller on eBay

I've been an ebay member for just over 20 years, and never found a 'world class' seller on that platform =)