Arrakis Console issue

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ChuckG
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Arrakis Console issue

Post by ChuckG » Sat Sep 02, 2017 2:20 am

Arrakis 2000SCT-12S console. One particular channel drops levels about 20 db when any other channel is put into either program or audition. All other channels play nicely with each other. Out of ideas, the dumpster is looking like a promising solution...but I'd really like to fix it if possible. Ideas?
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Chuck Gennaro
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davek
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Re: Arrakis Console issue

Post by davek » Sat Sep 02, 2017 2:32 am

Just a guess: it sounds like that channel has a faulty op-amp that might be dumping DC onto the PGM or AUD buss when the channel is enabled... hard to say without seeing the circuit documents though.

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kkiddkkidd
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Re: Arrakis Console issue

Post by kkiddkkidd » Sat Sep 02, 2017 7:13 am

I concur with davek. I recall that those consoles are DC coupled from one end to the other. Or there is something wonky going on with the VCA. Or yet another of those little tantalum caps has shorted...

I only have 2 old Arrakis consoles and one new Arc in use. I begged the customer not to buy the Arc but it was cheap.
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ChuckG
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Re: Arrakis Console issue

Post by ChuckG » Sat Sep 02, 2017 5:11 pm

I had considered that, problem is 11 of the 12 channels would have to have a fault.
When one particular channel is on -air, IIRC it's channel #5, putting any other channel in program or audition drops the level on that #5 by 20db. Any other combination of channels works fine. It has to be something in that #5 channel, but what....

Kevin, I have 5 Arrakis consoles still in service. It's a special form of torture.
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RGORJANCE
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Re: Arrakis Console issue It's a special form of torture.

Post by RGORJANCE » Sun Sep 03, 2017 7:40 am

Sorry to hear of your problems. I must have installed maybe 14 or15 of them of the 12,000 and 22,000 series with only very limited troubles over many years.

Most were switch tops breaking and there for a period of time, I lost some of the VCA chips until we got the latest versions. They were pretty reliable, and most were in high AM FM RF environments with few RF issues found immediately after installation. Only one site was RF difficult due to ancient wiring and very chaotic grounding inside the building.Thankfully only one console was tricky. Every time you added things, new antennas popped up that made extra work.

However, the portions of the board that were unbalanced weren't my favorite places.

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KPJL FM
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Re: Arrakis Console issue

Post by KPJL FM » Thu Sep 07, 2017 7:25 am

sounds like ch 5 has a bad chip, where it mixes it's signal to the buss(es). Got a print? Look for what applies the ch output (post fader) to those busses. Try swapping the chip with a different ch. See if the problem moves to the other ch. Tantalums around that chip would be suspect, also.
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Re: Arrakis Console issue

Post by ChuckG » Tue Sep 12, 2017 7:44 pm

Replaced the VCA chip, seems to be solved.
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Chuck Gennaro
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Bill DeFelice
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Re: Arrakis Console issue

Post by Bill DeFelice » Wed Sep 13, 2017 3:43 pm

I was buying the SSM2013 VCAs for the 1200-15 console I tended to. Keep in mind that the other channel's VCA would become wonky when the other chip took a dive, so it might prove beneficial to replace both channels if your board is indeed set up with two VCAs per channel.
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