Korg Forums

[voip]

Poor RAM connectivity seems to be a relatively common issue with computer-containing equipment of many types. In terms of what is actually going on, the topic is often discussed in a speculative way e.g:

https://forums.tomshardware.com/threads/why-does-reseating-ram-help-with-troubleshooting.3206498

The likely cause is probably a combination of RAM connector movement, relative to the RAM socket contacts, and contact oxidation and contamination. The relative movement can be caused by thermal expansion/contraction (e.g. room temperature variations, and warming/cooling from Kronos power on/off cycles), and by flexing of the connector and/or RAM, from vibration (e.g. from playing the keyboard, loudspeaker-induced vibrations), or flexing and torsional twist of the Kronos outer case being transferred to the motherboard, more likely during transportation, or handling on stage. When the RAM is first inserted (or reinserted), the contact that is made consists of metal to metal points of contact between RAM contacts and socket "pins" (basicaly sprung metal fingers), with the insertion process having created a "furrow" through any surface oxidation. If a bit of oxidation subsequently forms on the surrounding contact/pin material over time, and the RAM contacts and pins move relative to one another, that movement may not be sufficient to break through the oxide layer, and the contact rides up on top of it, and any wear-related debris plus contamination instead, leading to that connection failing to conduct current.

There is quite a bit of research on electrical contact failure mechanisms generally, though not RAM specifically. See e.g:
(institutional access, or payment is required to view the full papers, but the abstracts at least give a taster)

https://ieeexplore.ieee.org/document/170823
https://ieeexplore.ieee.org/document/7355086
https://link.springer.com/referenceworkentry/10.1007/978-0-387-92897-5_424 (from the Encyclopedia of Tribology - yours for £2,999 in hardback;-) )

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[wildebeest]

That all makes a lot of sense and certainly resonates with my sometimes hurried transportation of my board. Also, when the dreaded black screen of death first appears, its usually after a good few hours of rehearsing/gigging when its probably got hot and expanded inside. The black screen is a regular visitor, cold or hot, thereafter though. Thanks all for your help and thoughts.