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Adam-V
Joined: Jan 29, 2007 Posts: 300 Location: Australia
Audio files: 1
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Posted: Tue Feb 03, 2009 2:23 pm Post subject:
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How are you going with this rj?
Cheers,
Adam-V _________________ Digitalis Effect | Fractured Symmetry (www.spiralsect.com) |
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rjd2
Joined: Sep 02, 2007 Posts: 236 Location: philly
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Posted: Tue Feb 10, 2009 3:24 pm Post subject:
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hey adam, thanks for the check-in! no progress here. i had to slide out to EU for some gigs, got back yesterday.
alas, i think i need a break from "intensive troubleshooting type DIY" for some "instantly gratifying module works type DIY". gotta recharge my batteries. hopefully will pick this up at some point soon.....its alot harder to bail on a module once the front panel is made, though..... |
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Adam-V
Joined: Jan 29, 2007 Posts: 300 Location: Australia
Audio files: 1
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Posted: Wed Feb 11, 2009 2:39 pm Post subject:
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OK. Let us know how you go with it when you do get back to looking at it.
Cheers,
Adam-V _________________ Digitalis Effect | Fractured Symmetry (www.spiralsect.com) |
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macumbista
Joined: Sep 12, 2007 Posts: 398 Location: berlin
Audio files: 3
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Posted: Mon Jul 16, 2012 1:44 pm Post subject:
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Looking at a dead VCO myself. Have another, working one just next to it for comparison, but damned if I can find the difference. I've swapped out ICs, checked for shorts, polarity of diodes, everything. Wondering if I have to consider replacing the FET or (hopefully not!) the matched transistors.
How could I check if the FET or any of the transistors are bad before ripping them out? _________________ Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
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macumbista
Joined: Sep 12, 2007 Posts: 398 Location: berlin
Audio files: 3
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Posted: Tue Jul 17, 2012 4:57 am Post subject:
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Thanks, Andrew. The FET is 2N4391 in both boards. Orientation is the same, one works and one doesn't. So that's not the issue.
I'm wondering if the FET or the transistors are bad somehow. A student did the soldering so I don't know if they got overheated, or static damaged in the case of the 3140 as all the ICs are socketed. Is the FET also static sensitive?
I'm about at the stage where everything else has been checked. But good advice to check from component side. Will report back. _________________ Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
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macumbista
Joined: Sep 12, 2007 Posts: 398 Location: berlin
Audio files: 3
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Posted: Wed Jul 18, 2012 3:42 am Post subject:
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At a certain point, it was easier just to touch each solder joint with the iron to make sure it was good. In the process I found a bad connection to the TL072 at the lowest right hand side of the PCB. All good now. Thanks for your thoughts! _________________ Esoteric drones and nonlinear distortion
Custom/handmade experimental instruments
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