Unsuccess  increasing RAM

Forum: Hardware Talk
Topic: Unsuccess  increasing RAM
started by: piccolo

Posted by piccolo on Mar. 16 2006,20:51
I haved my lover DSL running over 486/DX2 66MHz with RAM 16MB. Slow, but running.
But when i increased RAM from 16 MB to 64 MB not boot, not memory test, nothing.
I do not think this problem could can exist and i not have motherboard documentation.
My hardward not soport 64 MB memory or exist an jumper, an set, something to resolved it?

Posted by AwPhuch on Mar. 16 2006,22:22
Possible RAM missmatch

Double check to ensure you have everything seated properly and then if system will post do a memory scan!

Make sure all your connections are tight and well seated after making any physical changed to any machine (I have pulled cords loose and stuff by accident and didnt know) and I hate having to keep pulling the case off for something stupid


Posted by piccolo on Mar. 17 2006,11:04
Many tanks Brain.
I checked connections before write in forum.
This motherboard is very old, i thinks exists an compatibility problem.
Is motherboard av7542 with chipsets SIS85c471 and SIS85c407. Perhaps somebody have documentation.

Posted by skaos on Mar. 17 2006,11:14
Does the motherboard take 72 pin modules? If so, it may not accept EDO-ram. If it is 30 pin, the max may be 32 MB.
Posted by piccolo on Mar. 17 2006,11:29
Many tanks skaos
Motherboard have two slots for 72 pines SIMM memory and 4 for 30 pines SIMM memory.
I installed two 72 pines memories. Each memory have 32 MB.

Posted by piccolo on Mar. 17 2006,16:06
Now i understand!
486 and olds 586 (60 - 100 MHz) use type FPM (Fast Page Mode) memory and not compatibility with EDO (Extended Data Out) memory.
If my memory is type EDO then not compatibility.
Manufacturer ID RAM is: POWMEM 9646. If EDO or FPM ?. I that Not it knows. Somebody knows?

Posted by cbagger01 on Mar. 18 2006,18:55
You need to read the part number on the RAM chip itself.

But ulitmately, knowing the RAM type isn't gonna help your situation.  Either the stick works with your PC or it doesn't work with your PC.

FYI, some older MBs required the RAM to be installed in pairs (groups of 2 identical or nearly identical sticks per bank).

If you can find out your montherboard part number, you might be able to find an old manual in PDF format on the internet that will provide more information.

Posted by piccolo on Mar. 18 2006,23:06
Many tanks cbagger01. You have reason.
Part number on the RAM chip is: MT4C4M4E8DJ-6 and is EDO RAM. Well, not luck.

Posted by anaconda on Mar. 22 2006,21:40
You may have to modify the jumper settings in the motherboard to tell it what size the new memory is.

It is possoble that there isn't any autodetection of memory.

It is also possible that the motherboard takes memory in pairs, then you would have to have 2 identical memories.

I remember that when I had a 120MHz 486 I was happy that it had memory autodetection. My parents 33Mhz 486 didn't have it.

Posted by piccolo on Mar. 23 2006,10:34
This motherboard documentation difficult to find but is evident have memory autodetection because detects 16 MB when boot with a pair of 8 MB memories and detects 8 MB when boot with only one 8 MB memory.
This computer can to run with only one memory but i also had used 2 identicals 32 MB memories within success.
Tanks anaconda.

Posted by piccolo on Mar. 23 2006,10:58
Before i want to write: i also had used 2 identicals 32 MB memories without success
Posted by t4thfavor on Mar. 23 2006,13:20
I feel bad that I threw away a pIII 500 and a dual 550 with 512 of pc100 each and did not even bother to offer it to someone. I come into gobs of elderly hardware and will start to offer it up for the cost of shipping.
Posted by piccolo on Mar. 24 2006,10:46
I'm sorry, an interesting proposition but i write from Argentina. Many tanks t4thfavor, though.
Is important for me to recover old computers by installing DSL because i think that can be the way to carry education and technology to poor or displaced people of few resources.
Even more, that people will begin using Linux. Regards.

Posted by 300c_pilot on Mar. 25 2006,06:42
These motherboards can run eather 30 pin mem or 72 pin but not both. There is a jumper on the mother board that selects which one you are using. 30 pin mem was limited to 4 megs a slot and had to be installed in pairs. The 72 pin memory must be in pairs of the same type, edo or ecc was probably not supported on cheaper boards. Because it is showing 16 megs max with the 72 pin mem installed, I believe the jumper is still installed in the wrong place. The jumper is next to the 72pin slots. I believe that most of these boards supported 128 megs in the 72 pin slots.

I do have a bunch of old p2 350's & p3 550 boards I would give away if you pay shipping. I also have a bunch of old computers as well, free to those that want them. PM me if you or anyone is interested.

Posted by piccolo on Mar. 25 2006,14:08
Interesting information 300c_pilot, unfortunatly i give away that computer running with only RAM 16 MB but later i will return a search that possible jumper.
I not mentioned some strange: during boot with 64 MB RAM the computer hangs showing BIOS to detect 386 processor running in 16 MHz when actually is 486 processor in 66 MHz. Perhaps BIOS attempt or force to match system to RAM size due incorrect jumper setting. Existing 3 jumpers close to slots 72 pin but i believe they are for setting cache memory size. Other jumpers are far from slots.

International shipping cost is prohibitive. Is necessary an dedicated infrastructure for became it possible. Anyway, i appreciated very much your help and also all other replies. Tanks.

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