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Juno 60 - LFO Trigger strange behavior...


gilwe

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There's something strange going on with the LFO Trigger button on my Juno 60... With NO LFO delay applied art all, LFO mode is set to Manual of course, pushing the Trigger button it takes about half-to full second for the LFO to start sounding... I wonder if there's adedicated trimpot that determines the LFO minimum delay time... Will have to check if it behaves the same when in Auto mode though... :rolleyes: Any other ideas ?

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There's something strange going on with the LFO Trigger button on my Juno 60... With NO LFO delay applied art all, LFO mode is set to Manual of course, pushing the Trigger button it takes about half-to full second for the LFO to start sounding... I wonder if there's adedicated trimpot that determines the LFO minimum delay time... Will have to check if it behaves the same when in Auto mode though...
:rolleyes:
Any other ideas ?

 

The LFO trigger button was a Roland engineering screwup, IMHO. I'm going from memory here, but from what I remember the button has only one switch assembly and a support spring. The switch is on one side and the support spring on the other. Many of my customers complain about uneven or intermittent functionality, depending where they press the button.

 

The other issue is the button is really similiar to the round rubber contact cups found in Poly 6/61, Memorymoog, P600, etc... keyboard assemblies. These switches can be easy or impossible to repair. Some you can take apart, some are molded and cannot be opened without breaking. If it can be opened, then a cleaning can possibly be accomplished. Caveat - Many times cleaning is not enough and the contacts need to be replated, which is a service I do provide for keyboard assemblies, switches, PC board fingers, etc... What happens is that so much resistive material builds up on the contacts that you can end up with readings of 10k to 100K across the contacts when the switch is depressed.

 

These switches are found on the CR8000, TR808, Juno 6/60, I think the TR909, and probably others that I can't remember. Roland was out of them back in the mid 90's, but at times they do turn up stock so I cannot definitively say they do not have any.

 

Wes Taggart

Analogics

http://www.analogics.org/

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Hey, thanks flattop ! You're the man ! :)

 

I did clean it up simply by drowning it in alchohol for half an hour. I didn't work at all before I did that. Now it works, but as I said it had that delay once pushin it - might be because the resistance you mentioned. I'll check it out !

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since you said cleaning helped this probably isnt it, but sometimes faders (like the LFO delay one) will get dirty and automatically jump to a certain value (like .5-1 second LFO delay). so under normal circumstances, id also consider that. i think the manual LFO switch is still readily available. if not, check with chipforbrains.

mini

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Hey thanks Mini-YOU !

 

:D

 

Well, I guess I still have to check whether this happens in Auto mode or not. IIRC it doesn't... So I tend to go with flattop's assumption about the switch resistance... Will update ! Need to complete my OBXa's restoration first !

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