Amiga 2000 experts needed

[dava1973]

Hi Amiga experts out there! I picked up a few damaged 2000 motherboards lately and all the rev 6es have a strange pcb where the buffer chips to the onboard ram sits normally. See pic attached.
I didn't have time to investigate further, yet, but will desolder one and have a closer look,if it's not something common, that all of you know already about ..
Does anyone happen to know what these pcb are for? Maybe bugfix by C= ? Or an aftermarket mod? Thanks for any hints the community might have!

 

[pms]

I remembered having a picture with that specific pcb : It is labelled: "A2000 Piggy Bag Solution"
But when I google it, not much comes up.

 

[8 Bit Dreams]

It's so called "Tokuda Tower" - additional circuit to add extra refresh for RAMs...

Someone by Commodore bought wrong Ram Chips, it wasn't possible to use them without this additional refresh circuit, so this additional tower circuit was added..

 

[dava1973]

Thank you for your answers & help!! Good to know - never saw this before

 

[8 Bit Dreams]

Please be aware, it is better to remove it if You are going to install an extension like 2MB Megachip, otherwise it will hanging on the BUS and may cause additional load with unknown results affecting accelerator and Zorro cards...

 

[KPI]

Thanks, good to know!