ECS UM486V memory issues \ VOGONS

ECS UM486V memory issues

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First post, by Andrejka

Posted on 2025-01-13, 11:55

Andrejka Offline

Rank Newbie

Rank: Newbie
Posts: 1
Joined: 2025-01-13, 11:30

Hello community,

Maybe someone can suggest why my selfmade 4MB 30 SIMM modules are not recognized on ECS UM486V mainboard.

Mainboard works perfectly with 3 chip 1MB SIMMs (with one or two banks filled), but refused to start with 4MB modules based on Alexandru Groza SIMM PCB project.
ICs are removed from 72 pin 16MB SIMM with marking MH4M36DXJ-6 ( 8x chip M5M417400CJ + 4x M5M44100CJ).

Of course I exclude assembly and soldering mistakes.

Many Thanks

Andrej

Reply 1 of 1, by Horun

Posted on 2025-01-14, 02:56

Horun Offline

Rank l33t++

Rank: l33t++
Posts: 6908
Joined: 2019-09-19, 02:19
Location: USA

My guess is the chip density of those 4Mb simms. I know 9 chip 4MB simms work on it just fine. One example with Sphonglefan: Re: What retro activity did you get up to today?
note the pictures, 4 simms and shows 16mb in 4th picture.

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

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