Memory problem with iMac 266

[tk4two1]

I have an iMac 266 and just installed a new memory upgrade. I had a 32 MB chip and a 128 MB chip. I replaced the 32MB with a 256MB. After restart with a PRAM Zap. The system shows only 256 MB in both OS 10.2 and 9.2.2. I opened the Apple Sys Profiler and it showed that the bottom slot had 128 MB and the top had 128 MB. The 256 is in the top slot. I have the lastest firmware version 1.2 that should allow me to use the 256 MB chip in the mac. I'm stumped...

 

[Cheryl]

You have one of the five Life Savers.
First did you make sure you installed a
PC66-SO-DIMM ?
Second, did you make sure you seated the chip in properly?
Assuming that you did, go to the Apple Menu>Control Panels>Memory while in OS 9. As you select memory, hold down the option and the apple keys. This will open another section of the Memory control panel labeled Startup Memory Test. Select on, then close the panel and restart. If there is a problem with the new memory chip, it should tell you with an alert.

It could be that a) they charged you for 256 but sent you a 128 (Miss labeled?), or b) the chip is faulty and only 128 is working.

If you got a Apple hardware test CD with the iMac (I don't remember when they started including those) run that and see what it has to say.

 

[tk4two1]

I figured out the problem. It seems that 128 MB is the max installable amount per slot. There is a trick though to get the 256 MB to work. The iMac can read up to 128 MB per memory bank (not to be confused with memory slot) So what I need is dual bank memory, one with 2 banks of 128 MB to make 256 MB. This memory costs more and is harder to find. The reason this whole problem started what because I didn't specify to the reseller that it was going to be used in a Mac.