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DIY Stompboxes => Building your own stompbox => Topic started by: seten on October 16, 2019, 11:07:34 AM

Title: DD-3 Switching Circuit
Post by: seten on October 16, 2019, 11:07:34 AM
Hey, I have a dd-3 I'm trying to fix up - it doesnt pass signal except to the direct out so I'm gonna take an audio probe to it later today but theres another issue which I think has to be unrelated - the LED indicator only turns on when the switch is pressed down and immediately turns back off when its not. whats strange is the first time I took it apart and messed around with it it worked fine, and I havent done anything since other than solder the input and output jacks back to the board.

http://www.synfo.nl/servicemanuals/Boss/DD-3T_SERVICE_NOTES_3rd.pdf

I've been staring at the SW portion of this schematic for an hour trying to figure it out with 0 luck. Havent done a whole lot beyond mechanical switches.
Title: Re: DD-3 Switching Circuit
Post by: GibsonGM on October 16, 2019, 12:23:38 PM
It is probably one of those "Qs", or their associated parts.  Q2, Q5, Q7, Q9.     

Look at this, to get started:  http://www.geofex.com/Article_Folders/bosstech.pdf (http://www.geofex.com/Article_Folders/bosstech.pdf)

If you understand how this works, it should allow you to test them with a DMM to see what is going on!   
Title: Re: DD-3 Switching Circuit
Post by: seten on October 16, 2019, 01:50:31 PM
Quote from: GibsonGM on October 16, 2019, 12:23:38 PM
It is probably one of those "Qs", or their associated parts.  Q2, Q5, Q7, Q9.     

Look at this, to get started:  http://www.geofex.com/Article_Folders/bosstech.pdf (http://www.geofex.com/Article_Folders/bosstech.pdf)

If you understand how this works, it should allow you to test them with a DMM to see what is going on!

Thanks! Read through that, realized I'd probably have to shelf this till I do some more EE khan academy courses, then switched the delay mode off hold and yep that was my issue - whoopsydoodle.
Title: Re: DD-3 Switching Circuit
Post by: GibsonGM on October 16, 2019, 02:32:21 PM
It happens, ha ha!  Now you know how the switching works, though!  ;)