juno 6 problem, juno 6 doing weird things

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Learning to Wiggle
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juno 6 problem, juno 6 doing weird things

Post by lostpablo » Mon Jan 11, 2021 3:45 pm

hey guys, my juno 6 is doing weird things since i used it in unison mode (with key transpose and arp up during power on). when i play it, at some point all of the waveforms from the dco section stop working right, only noise, filter, envelopes and the lfo is working. the weird thing is, when i let it rest unplugged, it works for maybe 10min, then the dco section makes strange things again.
another thing is, when i put the bender fully right with dco full, the dco section is working normal..
like it has some disease or i dont know..
did someone experience similar issues with his juno? or a expert for synthesizers?

Don T
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Re: juno 6 problem, juno 6 doing weird things

Post by Don T » Mon Jan 11, 2021 3:54 pm

Try unplugging all the connectors, especially between the pitch bend board, and the voice board. It could simply be a loose/dirty connector, so unplugging them then reseating may help. Also, check the pitch bend board for cracks or loose solder joints at the connectors.

Learning to Wiggle
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Re: juno 6 problem, juno 6 doing weird things

Post by rich_de » Tue Jan 12, 2021 10:13 am

If you have access to an oscilloscope or at least a frequency counter that can do a few MHz, check the connection net at the collector of TR63, R420, and the clock inputs of the 8253s. The service manual says it should oscillate around 1.9MHz. If that stops oscillating when the voices drop out, verify the proper input on connection 21 (from Bender Board 5) through R398 as already suggested. When both tests are positive (master oscillator stops, but bender input is okay), it's time to debug the master oscillator in between.

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