The S2ACINS improves electrical safety and synthesizer and computer card cooling in the Synclavier II mini-systems.
The S2ACINS is a panel that mounts in the four innermost fan screws on
the back/inside of the 3U fan panel, to completely cover the AC wiring
on the terminal block and the rear AC power terminals of the AC
outlet(s) between the fans.
It is very common to have to access the cards behind that panel for any
type of service, meaning the fan panel has to be unscrewed, tipped
down, and supported on something below or pulled out on the wires and
set on top of the machine, and the stupid wiring of the Synclavier II
Control Unit is such that you can be shocked even when the power switch
is turned off!
Instead of using a proper DPST switch that would disconnect BOTH the line and neutral AC lines when off, NED just put the line (AC hot) through an SPST switch, then ran the neutral directly
to the terminal blocks and thus all the way through the entire system,
so that line and any voltage present (0v, 115v, 230v, a billion volts
from an electrical storm, etc.) is always there inside the CIM-1 Clock
Interface Module, the Sample-to-Disk ADX 16/DAX 16, and on the back of
the 3U panel with the fans and AC outlets, even when powered off, and
ran the line to an SPST switch. So even with the power supposedly
turned off, you can be shocked. The only way that's likely to happen is
on the back of the fan panel, where that voltage is exposed in several
Electrical shocks have occurred numerous times, just by leaning the back of one's arm up to the back of the panel while accessing the synthesizer cards. This problem is common to ALL Synclavier IIs.
All Synhouse fully restored mini-systems sold
with 230v Euro power in the first fifteen years had these connections
insulated and covered, but it was time consuming and a little hand made
Additionally, it greatly improves cooling of the computer cards and
synthesizer cards by completely sealing off the air between the open
front cable area and the front of the synthesizer bin. This means that
all the air in that front cable area has only one place to go, under
the computer bin or in the front of it, between the computer cards, up
through the slots between them, up into the synthesizer bin and between
the synthesizer cards, and then turn and be sucked out the front
through the exhaust fans. Without this, any air there is going to go
the shortest and easiest route, right up to the fans and out, having
not cooled anything. This way, any air in there will be cooling both
sides of each one of the cards.
This photo shows the standard mounting flush on the back surface of the fans:
This photo shows an alternate recessed mounting (in case more space is needed for cables used for MIDI, sampling, etc.):
Much needed for many years, available now in the Synclav.com Synclavier store.