Falcon + CUBASE AUDIO + SCSI - Experiences?

[exxos]

Without testing 75R I can't say. 62R is what's used. Without seeing how it was installed it's hard to say if anything is wrong. Did you fit the SDMA cap? as some falcons are not happy with it.

[whomper]

NoI did not install the cap as instructions stated it's not required. I may go back to it with the proper resistance and a cap at hand to see how it behaves.

[exxos]

NoI did not install the cap as instructions stated it's not required. I may go back to it with the proper resistance and a cap at hand to see how it behaves.

It would help to scope the signals with and without the cap in place. Also clear images of your install will help.

[whomper]

It would help to scope the signals with and without the cap in place. Also clear images of your install will help.

Will do once I get my Falcon back online. For some reason it now boots with black screen. I've created a new post for this new issue.

[whomper]

While waiting on the resistors, I did notice that with my current clock patch I'm not getting any audio clicks when the bluescsi streams, however once the Falcon is on for some time, probably reaching higher temp, I start to get those annoying audio crackles upon playback of a few audio files.

What could be temp sensitive that could cause this? Perhaps there is an aged component that is more affected by operating temp?

Lastly, Should I remove the top metal cover in order to allow for better air flow? I find it odd that there is complete air flow blockage with the top metal sheet, so the fan is probably less effective.

[mikro]

@whomper that's definitely related to clock patch and quality of signals, respectively.

I have had a very similar pattern on my CT2 Falcon, which pushes the signal quality on the old Falcon board to the limits.

The top shielding has only one function: to suck out the heat from the PSU/CPU via the "tunnel" to the fan. Or the other way around, I can't remember.

[whomper]

Update:

I've installed v4 clock patch including 100pF underneath and 62R in DMA (attached pictures). I've removed accelerator board and am stock setup.
I've tested 62 Ohm on each side of the trace and the resistor's other end, so signal is flowing.

I'm getting heavy DMA errors. Any thoughts?
What's the best way to test that the clock patch works for the other two signals and then the DMA one?

IMG_9906.jpeg

IMG_9905.jpeg

IMG_9904.jpeg

[exxos]

It is difficult to tell anything without scope readings the signals.. You could try temporarily bridging over that 62R resistor, it will push more voltage to the SDMA which may help. I have half a feeling I was considering 33R for some reason..

I would also continuity check the left side of that 62R resistor and make sure it connects to one of the output wires on the V4 board. I don't remember which one it was it was either the centre or the right-hand wire.

I don't know why there is such variations on what works with what falcon. My falcon will work with anything I throw at it.. Other falcons seem to be more problematic but nobody knows why yet. It's almost impossible to diagnose such issues when I can't replicate them with my boards.

Plus what was the results before adding the V4?

[whomper]

Here are some more testing results after installing the DFB1X.

1. DMA testing is now fully green. Strange... However
2. Audio crackles in Cubase. How does that relate with DMA testing being green, beats me...
3. Scope measurements across 5 testing points:

Right side of 62 Ohm resistor

62 Resistor.png

In1

In1.png

Out 1 (starting left)

Out1.png

Out2 - Leads to DMA

Out2.png

Out3

Out3.png

As you can see, it does not seem to smoothen the signal and Out2 (DMA one) looks odd and not like the actual signal that reaches the 62 Ohm resistor).

With the previous clock patch, DMA testing app was green but audio was broken, just like now, so no real change.

[exxos]

Thanks , those look normal.

Its odd placing in the DFB1X changes the outcome. Does tend to lean towards a power related problem or just the usual "bad grounding" on the Falcon. Its difficult to say. Though I think it points to not being a clock patch issue as your not seeing much change there.

Have you scoped the DSP clock ? IIRC its on its own OSC without any termination resistor. Faults from SDMA to DSP might not be SDMA and might be DSP related. But its only a guess as I haven't seen that behavior before. But I am aware some Falcons have very strange issues. Some people have bad DSP ram causing various issues.

Did you resolder the Falcon PSU connector ? Also replace the big bulk capacitor on the motherboard ?