Boss ME-8 multi effects unit adapter plug size

[Kenny202]

I got this old beast with a 100/14VAC BRC power supply and my country's power is 220v so I need to use a step up transformer.
No problems but it is a bulky thing with the BRC transformer and the step up transformer so I bought a 220/14VAC power adapter.

Problem is the plug on it doesn't fit my ME-8, too big. I also tried a modern Boss adapter (without turning power on) and that power jack didn't fit either even though the outside diameter of the jack is the same (Just over 5mm, 5.2?)

Anyone have any idea of what sort of jack I should be looking for? The only thing it says on the manual is to use a BRC power supply, but I am pretty sure the early GT series also used a 14v BRC power supply but had the modern size Boss adapter jack. I had a look in the service manual for the ME-8 also and the only thing I could get of that was what maybe an adapter spec or Roland part number, not sure.
HEC0740-010010 (13449728)
Any help appreciated. I am sure there will be an adapter or something available but unfortunately I live in remote Thailand and can't just pop into a shop and try it

[bigtone23]

According to this, the BRC is 3mm/6.5mm. https://www.thomannmusic.com/boss_brc230_netzteil.htm
I don't know the history nor if it used the typical 2.1/5.5mm jack before.