Re: Cubase and it's Nemesis...

From: citadel <citadel_at_indigo.ie>
Date: Sat, 25 Jul 98 17:33:07 -0000

Hello to Doug Little, Nick Ripley, Jo Even Skarstein, Richard
Rives and the Falconer's, et al.

Dear All,

==============================================================
Doug Little wrote:

>Can you explain exactly what happens, and under exactly
>which conditions (i.e. the state your machine is in at that
>time) and what things you are able to do in order to remedy
>the problem (even if it means disabling or removing something).
==============================================================
Richard Rives wrote:

>What SCSI driver are you using? What speed are you using?
>Check the wires for proper shielding.

I have HD Driver 7.52, either speed (Nemesis only)..and I have
checked both grounding and shielding...but why Cubase only????
==============================================================

My difficulties have all been related to Cubase running at
either of the two accelerated speeds. I have the most recent
Nenesis (25/50MHz) I did remove the two electrolytics as
instructed..(although upon further investigation, I've found
that makes little difference?). Even under the AB040 I'd like
to use Nemesis on low speed as I have the JAM Pro 8x8 and
need all the processing power this combination is capable of.

Cubase Audio will be sailing along..(sometimes for up to 20+
minutes and then there will be a slight flicker and that's all
she wrote. No warning flag appears or anything. The screen
just freezes. This only happens in Cubase at either low or high
speed. Falcon normal (16/32) seems fine. I've had no problems
with SCSI that I'm as yet aware of. I've done loads of transfers,
back and forth, HD to system...and also to other HD's with no
apparent difficulties.

When I first started the system following final installation of
Nemesis, and booted Cubase, I had terrible noise coming from the
speaker..(like AM radio static.) I found the level was control-
lable by moving the audio mixer faders up and down..(all the LED
simulated meters were going crazy. I started playing with other
resistor values on the white DMA wire connection. When I finally
got around to installing a 1K pot to ground with a .001 cap in
parallel with it off the (pin 110) U36 DMA connection I was able
to "tune" out the noise at both low and high accelerated speeds.

This has helped the crashing problem a great deal (With the noise,
Cubase would crash almost immediately) but eventually it will
crash again. So far this situation only occurs in Cubase! The
flicker appears to be some momentary discharge from somewhere.
Sometimes there's a colour shift...and when it freezes it's often
in mid-cycle so you might be left with a randomly coloured shadow
of some screen object, etc.

I will try more of those things you suggest. I understand Cubase
does something different with MIDI than most other programs? Is
it possible this problem is related to a component breaking down.
I do see this flicker very occasionally while in other programs
but they don't seem to be affected...perhaps not so sesitive?..go
figure.

===================================================================
Jo Even Skarstein wrote:

>I can't recall your original posting, but are you saying that you're
>having problems with Nemesis alone? If that's the case, is this at all
>speeds (16, 20 and 24MHz) or just 20/24?

As stated, just 20 and 25 MHz, in this case.

>If you've already installed the AB as well as the Nemesis, then just stay
>away from the accelerated modes. In 16/32MHz it should be stable, but
>getting stable SCSI in 20/40MHz is quite a job.

No AB040 yet...still trying to solve the Nemesis problems!

>Not all of these tips are directly related to SCSI-stability, but anything
>that improves stability in general will do. I've done all the above, and
>while the Falcon itself is 100% stable in 40MHz now, SCSI and floppy still
>doesn't work >32MHz...

I will follow all your tips...(most were done). SCSI stability
does not appear to be the issue...even my floppy works at the high
speed. It's just Cubase..(the main, perhaps, only reason I did all
of this in the first place.). My gut feeling still says DMA but
why only problems with Cubase. Someone mentioned some weird thing
Cubase does with MIDI..that the line going over to the MIDI chip
might need to have a manual switch on it..only for Cubase???? Any
thoughts?

Thanks to all..I hope youse "brains" can sort me! [|:-)

With regards,

Michael Anthony

Ps. Below are my earlier postings on the problem...assuming you've
the time and/or inclination to continue reading.. (G)

=====================================================================
First letter:

>On my towards the 040, I've installed the Nemesis and buffer mods.
>I now have the Falcon up and running fine except for one major
>difficulty. (My Nemesis is one of the most recent issues with the
>50MHZ clock for high speed operation.)
>
>Nembench readings appear normal with both DSP and processor at 156%.
>..that is until I boot Cubase 2.06! (All other programs so far seem
>to be okay...this also includes Audio Tracker.)
>
>Upon booting Cubase, it loads and the default screen comes up. In a
>matter of a few seconds or so the system locks up. In subsequent
>attempts to get it going I've found loads of what sounds like AM
>radio static coming from the int. speaker...also the audio mixer's
>graphic display registers a great deal of noise in each of the led
>style indicators. It stops the moment I quit the program...and if
>I manage to quit in time the computer continues to function.
>
>If I manage to quit before it freezes and then run DSPBENCH and
>NEMBENCH I find the system has been knocked back to 40MHz (125%)
>If I then reload Cubase it's still pretty unstable but the noise is
>gone. The other interesting thing is that the NEM_ACC.ACC (speed
>indicator) still shows "High" speed!
>
>One other thing that may be normal is if I load in only NEM_HI.PRG
>at boot up without NEMESIS.PRG, the system according to NEMBENCH is
>at the high speed but the accessory shows Nemesis as being off. Like
>I said, more than likely normal.
>
>If I set Nemesis to Low speed (40MHz) Cubase appears to behave with
>no discernable noise. I'm mainly doing these speed mods to assist the
>situation with Cubase. I've no idea why only Cubase (so far!) has
>been affected. Can anyone please shed some light on both possible
>reasons and hopefully a cure? DMA-SCSI operations seem fine at any
>speed. It appears to be connected to something with the DSP...and
>only with Cubase.
>
>If other operations didn't appear to be okay, I might suspect that
>I've made a mistake somewhere...(still quite possible) [|:-) Thanks.

======================================================================
And the second: (I found that using the recommended DMA mod that
the computer was being forced down to the next lowest speed when
going into Cubase)

>Update.
>
>If I raise the value of the resistor in inductor/resistor
>combination on pin 110 of the U36 to ground (Pin 14 of U20)
>the computer is not forced down to a lower speed setting.
>(I used a 1k ohm resistor.)
>
>Doing this enabled me to find out that the computer was
>previously being forced into a "no" Nemesis state while
>running Cubase...(I thought it was running at Low speed).
>After changing this resistor to the indicated value above,
>the noise was evident when set to the Low setting as well.
>The system is very unstable, crashing constantly when
>Nemesis is on and at either speed with Cubase running.
>
>I reset the DEF.ALL file with no volumes in the Audio Mixer
>...(these levels actually control the output of the noise..
>if all turned down, it's quiet). I also set the speaker to
>on and resaved these settings with the file. I did find
>that it wasn't quite so quick to crash as long as I didn't
>turn up the noise.
>
>All these difficulties seem to relate to the running of
>Cubase only...the one program I need to have working! Where
>could this noise be coming from and why? I've gone over my
>wiring a 100 times...here comes 101!

Eventually I sent a letter to Doug outlining the mod I made
to tune out the noise with the adjustable potentiometer and
cap outlined above. I'm now preparing to change buffer chips
and replace the DMA wire with a shielded one. Thanks again.


=====================================================================
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Received on sø. juli 26 1998 - 00:05:00 CEST