Digital Glitch using Adat, problem 1 with recording system Options

[Cpt Horse]

I've Being using (for quite some time now, about 4years)

Mac G3 266MHz 96meg ram
OS 7.6
Korg 1212 i/o audio card
Alesis Adat
Cubase v3.5
all running at 48kHz sample rate
the audio card is the master time clock source
the adat sync to the audio card

i use the Adat as a digital interface with cubase
eg. 8 channels analogue directly in to the adat then routed via the optic cable to the korg 1212 i/o.This gives me 12 channels of simutanous recording with the analogue and digital inputs on the audio card

this system is rock solid and it has never failed me as a basic recording tool.
and is used in a profesional studio.

But with one little problem thats now starting to bother me.
I get what apears as a random digital glitch while recording,
its a 'tick' noise, it will peak above 0db and only on any one channel of the incoming 8 from the adat. it might happen once every 5 to 10 min or once a day. in the pass i would just zoom in on the recorded data and edit it out.  

what i want to know is if anybody else has a simular system as the one above with the same problem or if any one might know what might be coursing it?

thanks.
Cpt Horse  

[DigitMus]

My first guess would be hard drive issues. Are you recording to the drive that has your system/recording software on it? If not, is your second drive on the same buss as the startup drive? Do you optimize the drive before recording to ensure CONTIGUOUS free space? Are there any background apps running that might be trying to access the drive/buss during recording? Are you recording to a high speed (7200 or 10,000 rpm) drive? Does the drive have thermal calibration disabled? Do you use a custom system set-up for recording (i.e. all extensions/control panels not needed for recording disabled)?
Any of the above factors could introduce glitches in the recording process, and there are probably some I haven't thought of yet. I've used the 1212 IO/ADAT combination on a powermac 7300 & a B&W G3-400. I use a separate ( high speed) drive on its own buss, optimize before recording, custom system configuration, virtual memory off & lots of ram assigned to [Cubase, Deck II, whatever].
I hope some of this information is helpful.

Scott