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| | |-+  buss output on unassigned channels
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Author Topic: buss output on unassigned channels  (Read 1128 times)
windmill
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« on: March 22, 2016, 04:34:36 PM »

Hi,

Console is 528b

One of my channel busses (channel 12) is outputting to all other recording buss outs.

When I try to send out of the buss (12) the signal from the channel preamp is showing up on all other busses/tracks being recording as well.
Example:  Channel 12 preamp bussed to Channel 12 output is sending signal to all other bus outs.

If I assign to a different bus out of the channel it works as expected and only outputs on that bus.
Example:  Channel 12 preamp bussed to Channel 1 output is fine and only outputs signal from bus 1

Anybody experience this before?
Thanks!
« Last Edit: May 08, 2016, 03:41:17 AM by windmill » Logged
kakumei47
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« Reply #1 on: March 31, 2016, 02:30:49 PM »

I've never seen this one. It's a little weird because the channels routing is based on the switches at the top of the channel and it Would be very strange to have all switches failing at the same time, especially if it's only when 12 is depressed. Could there be some mod made on that channel? Can you see anything visibly different on that channel?

Does it still happen in the same way when you switch it with another IO module (like if you trade it with 11, does the problem follow the module or stay with that slot, or disappear altogether?
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windmill
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« Reply #2 on: April 02, 2016, 12:47:48 AM »

Thanks for the reply:)

The problem stays with the module regardless of changing slots.

I'm thinking bad opamp in the Chanel bus driver?

Thanks again!
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Harrison
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« Reply #3 on: May 04, 2016, 11:47:37 AM »

No it's not.
What happens if you move the module to another slot? Same thing? ie 12 busses everywhere.
If you move iy and sawap 12 and 13, you might find it now does it in 13.

It's more likely the ACN on 12. This might be bad and sending the signal along the ACN common to all the others.
You might see by winding the buss trim away from the calibrated switch position.
put the console into tracking mode with both status buttons up, rotate the buss trim away from the switch on a good channel see if the track meters kick; (ie a DC thump) now do it on 12. You might see all the meters kick. This certainly can be seen on LM meters in peak mode.

The ACN common is the only thing goes to all channels without some form of isolation.
Hope this helps
PC
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windmill
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« Reply #4 on: May 07, 2016, 11:02:06 AM »

Thanks for the help:)

Problem solved:  it was a bent op amp  leg on the channel output amp IC700...one of the legs was not seated properly and was touching another leg as well.

Thanks again!

« Last Edit: May 08, 2016, 03:38:24 AM by windmill » Logged
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