Analouge Input very noisy

[Showcase]

All of a sudden Its flying all over the place in the Analogue Input test!

When disconneting all ribbons(or switching of the buckets) it goes silence, which first made me believe it was something in the console or PSU but that doesnt make sense to me.
Could it be the Analog In card has become to sensitive for whats coming in, not filtering right or something?

[kilmister]

Perhaps you've accidently changed threshold level? You can change it simply by pressing a coresponding number. Typical threshold is 3 or 4.

-Paavo

[Showcase]

Hi, thanks for answering!

I think it was set to 4 by default, I´ve tried to change it to even higher values and at 8 its fairly quite.

All this quick little movements is ofcourse recorded when trying to do a mix so Im filling up a whole disk just for a 4 min song and something is wrong, could it be that my VCAs
actually are giving wrong voltages because of power issues to the console? (though it doesnt seem to be any problem there)

[kilmister]

If it isn't about treshold, then make sure you have correct voltages and there's no ripple.
If you find any ripple, recap your PSUs regulator boards.

-Paavo

[Showcase]

If it isn't about treshold, then make sure you have correct voltages and there's no ripple.
If you find any ripple, recap your PSUs regulator boards.

-Paavo

Can I higher the threshold while mixing, and not only in the test menu?

[kilmister]

Noup. Threshold setting is a test tool to give you an idea how much noise you have in your VCA lines. If you have to set it up to 8, it's way too high and you have some sort of problem. I suggest you to check your voltages sooner than later. If the problem is in the PSU you should fix it immediatly.

-Paavo

[kilmister]

Forgat to mention:
Check both, console and computer PSU rails.

-Paavo

[Showcase]

Forgat to mention:
Check both, console and computer PSU rails.

-Paavo

Thanks!

Dont know how to do those measurements so better wait for a tech
I have 2 PSUs so cut off some buckets and tried with one PSU, and then switched to the other PSU but no luck, will have a look at the changeoverunit now.

[Showcase]

Thanks for the help Kilmister, I PMed you instead!

Any other suggestions or how to rule out things here is much appreciated 

[kilmister]

Let's keep it public, might be useful info for someone else having same kind of issues.

Refarding your tests with your PSUs it looks like problem is not there.
I would check how VCA line voltages look like. You need a scope to see what kind of noise there is. Measure most noisies channel. Find measuring point from schemos at VCA card. Maybe it gives a hint what's wrong.

Do you have Totall Recall?
If yes, check you have all ribbons connected at the card below keyboard. Unfortunately I'm not next to Service Manual at the moment and don't remember card number.

-Paavo

[Showcase]

Let's keep it public, might be useful info for someone else having same kind of issues.

Refarding your tests with your PSUs it looks like problem is not there.
I would check how VCA line voltages look like. You need a scope to see what kind of noise there is. Measure most noisies channel. Find measuring point from schemos at VCA card. Maybe it gives a hint what's wrong.

Do you have Totall Recall?
If yes, check you have all ribbons connected at the card below keyboard. Unfortunately I'm not next to Service Manual at the moment and don't remember card number.

-Paavo

Good thinking

I have TR, checked the ribbons under keyboard and they seem fine.
The problem now is that the VCA behaviour has totally vanished without a trace again so I´ll have to wait until next time hehe, in the meantime Im gonna try dig up some schematics to give me
some ideas where to start doing measurements.

Thanks, Ill be back!

[Showcase]

Im sorry I need to revive this thread, the problem is back

When running old mixes it seems to behave, so Im guessing Analouge out is fine, setting up a new mix and the bargraphs are moving some, and VU meters when in (VCA´s to meters) are going forth and back aprox. 1 db
Turning off/bypass computer and the VCA´s seems steady again

[Showcase]

Fixed this problem.

Solution was that we seem to have an even bigger problem with the grounding/earth, the ribbons going from faders etc.... was shielded with tinfoil and copper connected to ground to prevent interference, instead their is some leak of current in the ground which made it all worse. So... not good, calling an electrician today,

[marcmozart]

Every day of downtime sucks. On the positive side, we will get so much better over time analyzing problems on our consoles!

[Showcase]

Yes, thats why I think its important to write a solution/what was wrong... It could help someone else maybe

But this leak of current to earth is not good, and I think very hard to track down, could be anything :/