Audient ASP8024 Metering Problems

[cbarrett92]

Hey guys,

At the place where I work one of the power supplies went out and we had to order a new one from Audient in order to get the console back up and running. But now we have a strange problem with our metering.

While there is absolutely no signal going into the console, all the meters show a LED or 2 of signal, even though there is nothing audibly going through the console. The problem will go away temporarily if we power off the console overnight, then the problem wil go away only temporarily for a couple of hours. Everything else in the console seems to work as it used to.

My thoughts is that when the old power supply went that it damaged and internal voltage rail for the metering circuits. Does this sound like I'm on the right track to anyone?

I will be opening the console tomorrow to see if any of the usual suspects are about (blown caps, diodes, resistors, etc.)..

 

[cbarrett92]

Also in the master section metering. Note there is no added noise on the master bus... It is strictly in the metering.

 

[pucho812]

if it's showing up on the meters, there has to be a way to measure it. Sure it's not audible but that doesn't mean it's not there.

 

[Rochey]

High frequency switching noise coupling to your metering ground?

Too high for your hearing, but enough amplitude to modulate the ground reference?

 

[TomWaterman]

Hi cbarrett,

I just got alerted to your thread (I don't spend much time here anymore).

Question first:

Is your console a 48-frame and has two supplies? Your post suggests it from "one of the supplies failed" - if so it might be possible that you have two of the older PSU designs. On a 48-frame with those supplied, one would power the audio path and the other supply would drive the meterbridge.

If you replaced the supply that drives the audio path - that should be OK, so first thought is to check the rails from the supply that wasn't replaced - and then search inside for a bad 0v ground connection from the meterbridge back to the supply. Ground bus could be poorly connected or damaged - look for connector burn also on molex headers.

If your console has two newer supplies (or indeed just one) then it is likely something else - if you can create a support ticket on our system (https://audient.zendesk.com/home) either myself or Gerald (our service engineer) can get you some more documentation and advice etc.

We should be able to get you going soon enough.

Best,
Tom (now working for audient...)

 

[cbarrett92]

Hi Tom,

I submitted a support ticket. I will post the solution I find to this problem just for curiosity and reference once we get it all sorted out.

Thanks

 

[cbarrett92]

Well I might have found the problem or one of them. This was right behind the master section metering. Seems to have really burnt up. It tore up the PCB and almost burned resistors R1-R5 for the power status LED's.

Had to replace those resistors and solder in a flying lead disconnect for the power input because the board is too tore up for another 6 pin Molex...

But it makes me wonder what could cause this? None of the power traces on the board were burnt up (except right at connector). Would this indicate some sort of high resistance connection in the Molex causing it to burn?

Will install and update tomorrow.

 

[Brian Roth]

YIKES!

 

[TomWaterman]

Hi Chris,

this is an issue we have seen on some of these power inlet Molex connectors. David thinks it may be something to do with turn on current draw on the negative rail and some form of arcing / electroplating between pins which causes the connector to burn out.

If you hardwire to the main PCB then this will not happen again. I can't remember off hand but think we may have changed the connector type on newer consoles. It seems to only happen after a very long time - however I've not heard it cause the symptoms you have had here (meters) - we have heard clicks in the master output signal path sometimes.

Did you verify that your 0v ground returns were nicely leading back through the Y-split cable to the PSU from the meterbridge?

-T

 

[TomWaterman]

Looks like both rails took a hammering in the connector. This may have happened when the old supply died.

-T

 

[TomWaterman]

Hi Chris,

did you get any further with this?

-T