Jupiter 6 repair help hecka needed!1r

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noisecomm
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Gear: Ensoniq ESQs & Sq80s, various Junos & an odd jx-3p, Korg & yamaha units & a Rhodes Suitcase 73. SIG
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Jupiter 6 repair help hecka needed!1r

Post by noisecomm » Fri Jun 28, 2013 7:53 am

I've been nuts deep in a Jupiter 6 trying to figure out why it won't power on. The tranny is showing 6v at every tap.

So, is there a reasonably cheap replacement out there and has anyone dealt with a rectifier/re-cap on one of these?

Any help would be greatly appreciated. :la: :happy3:
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noisecomm
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Re: Jupiter 6 repair help hecka needed!1r

Post by noisecomm » Fri Jul 05, 2013 9:51 am

please help..... :banghead:
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garranimal
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Re: Jupiter 6 repair help hecka needed!1r

Post by garranimal » Fri Jul 05, 2013 4:20 pm

You're showing voltages at the transformer, I'm assuming on the secondaries? Remember at the transformer these will be AC voltages so the DVM might be reporting averages. So the switch must be good. The power on switch went out on mine three years ago. Replaced it with an illuminated switch and looks great.

Don't assume the transformer or diodes are bad, find evidence to back up this idea. It may be due to the power supply pulling too small current due to component failure in one of the circuit branches.

Download the service schematics and verify the power supply output voltage at each point. It should indicate which circuit branch in the PS may have the failed components. The failure may also come somewhere after the PS board, so this is why you might take off the connectors to isolate the PS board and see what the PS is putting out irrespective of the rest of the synth. As always be careful doing any testing while running power. And there's no shame in taking it to a synth tech that you know and trust, there's some peace of mind to be had in that.

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Re: Jupiter 6 repair help hecka needed!1r

Post by neanalog » Sun Jul 14, 2013 2:57 pm

I agree with garranimal. I repair synths for a living and I have seen a lot of bad things happen from novices taking on power supply issues. (I don't know what your level of knowledge and skill is.) If your meter is on DC volts, you will get a reading like 6v on all of the transformer windings. I very rarely see failed transformers, though it does happen from time to time. With the multimeter set to DC volts, check the output of the +5V, +15V, -15V. Are any of these correct? Remember that the transformer here has two secondary windings, and two bridge rectifiers. This means that if you aren't seeing anything on any of those outputs, that the chances of BOTH windings, or BOTH regulators being blown are very slim. Based on that knowledge, we can then point to only a couple things, those being the primary winding of the transformer, the wires leaning from the switch and the noise filter, and the switch. I'm not looking at the schematic right now, but I believe there is also a capacitor between the plug terminals. If it were shorted, you would blow a fuse in your breaker. If you are getting only +5, or only +/-15, then you have a problem with your power supply and will need to chase that down. I usually disconnect the power from each board and test, to be sure that one of the rails on one of the other boards isn't shorted. Hope this helps.
-Rob C
http://www.newenglandanalog.com

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Re: Jupiter 6 repair help hecka needed!1r

Post by neanalog » Sun Jul 14, 2013 4:56 pm

By the way, if you need someone to fix it and don't mind shipping the unit, we can do it. PM me if you need it serviced.
-Rob
www.NewEnglandAnalog.com

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