SSL6000 rapid pulse noise on mains. All channels down

[jwhmca]

It's a pretty low noise. All the channels are down. Can't see it bouncing the VU's but the level is pretty low. Any thoughts? Things to test?

 

[pucho812]

If it's across the board it's going to be a PSU issue. I have had it where wires over time break due to heat in the PSU on the 4000 series so might be the same thing. Look in perticular to the wires going to and from the the large amp rectifiers

 

[bruno2000]

What meters do you have? Plasma?
Best,
Bruno2000

 

[jwhmca]

VU Meters, not plasmas

 

[bruno2000]

Automation computer?
Best,
Bruno2000

 

[jwhmca]

yes it has total recall

 

[bruno2000]

Same noise with ribbon jumpers in and computer off?
Best,
Bruno2000

 

[jwhmca]

ahhh. sorry, "ribbon jumpers" is new to me!

 

[bruno2000]

I'll see if I can find the docs.  Ribbon cable connectors that have the first 10 (?) pins jumpered to the last 10 pins that you plug into the console where the computer ribbons plug in.  Bypasses the computer VCA control voltages.  I'll pull one out and take a photo.
Best,
Bruno2000

 

[bruno2000]

Sorry, first 10 into next 10.  Getting the photo now.
Best,
Bruno2000

[edit:  added photo]

 

[jwhmca]

So you turn the computer off, then plug that into where?

 

[bruno2000]

You unplug the ribbon cables under the patch bay (one from each bucket, one (I think) from the 651) and plug these jumpers in, bypassing the fader control from the computer.  You now have a completely manual console.
Best,
Bruno2000

[edit: spelling]

 

[Walrus]

I had a very similar fault this week, (4K desk) except my noise was at 500 Hz. All evidence pointed to a PSU fault as when hitting a Solo button (more loading from all the Cut lights) the noise got worse.
However switching off buckets as a last resort to eliminate the desk, showed it to be coming from the A-H bucket. Turned out to be a faulty 79L15 on the VCA card on the D channel!

 

[jwhmca]

I had a very similar fault this week, (4K desk) except my noise was at 500 Hz. All evidence pointed to a PSU fault as when hitting a Solo button (more loading from all the Cut lights) the noise got worse.
However switching off buckets as a last resort to eliminate the desk, showed it to be coming from the A-H bucket. Turned out to be a faulty 79L15 on the VCA card on the D channel!

Even with all the channel faders down?

 

[Walrus]

Yes!

 

[pucho812]

Not sure how far you have gotten on this but after some current posts,  if it were me, I would kill power to  all the buckets including center/master section.  I forget where the power switches for the buckets and the master section are. On our 4000 they were under the producer desk/patchbay area on the left hand side.  From there turn on the center section only. then turn on each bucket one at a time and see if and when the noise starts, assuming it has not done so already. This will narrow down the search of where to look. Console fault finding and repair is all about taking the big picture(console and PSU's) and making it smaller, until your down to that one section of the board then going from there.