Amiga 4000 ram troubles

[MrPixel]

On my amiga 4000 mobo rev.B 68040 i get strange error from rams. Every bank see only 1mb instead of 4. Jumper j852 is set correctly in 1-2 position. Ram banks is naturally 4mb.
when type the "avail" command maxumum size is 1024 for each ones.
Does somebody know this problem ?
May be ramsey may be false contact ?
Please helps or hints are very much appreciated.

[amiga4001]

I have had the same problem as you.
Somebody soldered all simmholders new to it(were already broken so had to) and replaced the latch? small ic close to RTC cirquit.
Look closely if no acid has found it's ways to the via's especially under the simmsockets.

[MrPixel]

Thank you, do you have then solved using this method?
I have no acid on the simm bank.