I have had trouble getting DUSGs to work as well, and there is a technique I've found that seems to help quite a lot.
I print out the picture Ken has on the webpage that shows the PC board traces. I then sit down with that page, a highlighter, the pc board, and an ohmmeter, and I check every single trace for continuity. The traces on these boards are somewhat fragile, especially if you use lead free solder (which requires higher temperatures). Just be patient and you can get through the whole thing in an hour or two. Whenever I've had a DUSG failure, this has found the problem for me.
That being said, I'm troubleshooting a friend's VCS right now, and this hasn't helped a bit ;-)
Anyway, give that a try. Chances are you will find an open trace.
Gary
I print out the picture Ken has on the webpage that shows the PC board traces. I then sit down with that page, a highlighter, the pc board, and an ohmmeter, and I check every single trace for continuity. The traces on these boards are somewhat fragile, especially if you use lead free solder (which requires higher temperatures). Just be patient and you can get through the whole thing in an hour or two. Whenever I've had a DUSG failure, this has found the problem for me.
That being said, I'm troubleshooting a friend's VCS right now, and this hasn't helped a bit ;-)
Anyway, give that a try. Chances are you will find an open trace.
Gary
--- In cgs_synth@yahoogroups.com, "adematteo" wrote:
>
> Not sure if this is the best way to do this ? but figured if someone in the future searches better to have a few problems in 1 thread.
>
> Anyhow, i have 1 (1/2 of the board) of my dusg's working perfectly and the other not working at all as expected.
> The problem is no recognition of a trigger input or signal in for that matter unless i have the fall pot full cw then it seems to go into a slow self cycling.It needs a trigger to start this but does not sync with the trigger at all.As soon as i back off to about 2-3 o'clock it stops.
>
> These are the things i have checked/verified against the working half:
>
> -All ic;s getting and sending the same voltages as working half
> -Diode orientations
> -resitor values
> -Transistor orientation,proper part,voltages the same as working half
> -continuity through path of trig in to output
> -checked for solder bridges
>
> I'm out of ideas so i will really appreciate it if someone has some advice !
>
> Thanks, Tony
>
> --- In cgs_synth@yahoogroups.com, richmolindarius@ wrote:
> >
> > Fully agreed. The USG is my fave by far with the SSG following up in a close 2nd. :D
> >
> > On 2012-10-11, at 12:06 AM, Stephen Richards wrote:
> >
> > > My all time favourite Serge function block , DUSG rocks.
> > >
> > > ________________________________
> > > From: Rico Loverde
> > > To: cgs_synth@yahoogroups.com
> > > Sent: Thursday, October 11, 2012 1:51 PM
> > > Subject: Re: [cgs_synth] Re: CGS114 DUSG problems/troubleshooting
> > >
> > > awesome!!!
> > >
> > > On Wed, Oct 10, 2012 at 7:26 PM, ch1nard wrote:
> > >
> > > > **
> > > >
> > > >
> > > >
> > > > okay awesome, that was totally it
> > > >
> > > > Now other than the fact that i have the pots wired backwards DUSG seems
> > > > functional!
> > > >
> > > > --- In cgs_synth@yahoogroups.com, "ch1nard" wrote:
> > > > >
> > > > > ah yes, you appear to be correct good sir :)
> > > > > this would be reverse orientation for all trannies? (2N3904 and 2N3906)
> > > > >
> > > > > i will switch them around after i get home from work and see if that
> > > > fixes things up.
> > > > >
> > > > > might need to hit up the parts store on the way home in case i pooched
> > > > any of them from being in backwards
> > > > >
> > > > > --- In cgs_synth@yahoogroups.com, sasami@ wrote:
> > > > > >
> > > > > > Also make sure you are using the right sort of tranny! I had people
> > > > with
> > > > > > this problem on another project - and they had used the wrong sort of
> > > > tranny.
> > > > > >
> > > > > > >Are the trannies situated like the silk screen on the pcb or
> > > > reversed? They
> > > > > > >should be reversed.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >On Tuesday, October 9, 2012, ch1nard wrote:
> > > > > > >
> > > > > > >> **
> > > > > > >>
> > > > > > >>
> > > > > > >> Okay, i have been staring at this for almost a week without making
> > > > any
> > > > > > >> progress so its time to start asking around for help on figuring
> > > > out what
> > > > > > >> might be wrong with my DUSG build
> > > > > > >>
> > > > > > >> I am running this off +/-15v power supply and i have all the
> > > > connections
> > > > > > >> appear to be correct with no magic smoke escaping
> > > > > > >>
> > > > > > >> What is happening is that the output lights are lit up constantly.
> > > > > > >> When i hook it up to a scope it appears that both halves are cycling
> > > > > > >> (triangle) at about only 300mV p/p
> > > > > > >> -fiddling with the rise/fall gives minor variations but is still a
> > > > > > >> triangle. (never hits saw or ramp)
> > > > > > >> -feeding LFO into VC in shows the same minor variances as fiddling
> > > > with
> > > > > > >> the rise/fall knobs. bipolar control seems to work
> > > > > > >> -feeding a signal IN combines the signal with this triangle
> > > > oscillation
> > > > > > >> -trig and end do nothing
> > > > > > >>
> > > > > > >> now everything 'appears' to be wired up correctly and there were a
> > > > couple
> > > > > > >> of lifted pads that i was able to jumper patch around.
> > > > > > >> building this as part of a 'best of cgs' BOG panel, so the wiring
> > > > is well
> > > > > > >> documented.
> > > > > > >>
> > > > > > >> I have verified +/- voltage being delivered to all the TL072's and
> > > > > > >> verified + voltage for the LM3900's
> > > > > > >> ground appears to be delivered as well.
> > > > > > >> all the trans are correct value and orientation (2N3904 and 2N3906)
> > > > where
> > > > > > >> applicable
> > > > > > >>
> > > > > > >> Anyways, eyes are too tired to look at this anymore tonight...
> > > > > > >> time to smoke a bowl and watch some doctor who.
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >
> > > > > > >
> > > > > > >--
> > > > > > >________________
> > > > > > >rico loverde
> > > > > > >415.596.6255
> > > > > > >ricoloverde.com
> > > > > > >
> > > > > > >
> > > > > > >[Non-text portions of this message have been removed]
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >------------------------------------
> > > > > > >
> > > > > > >The CGS Modular Synth home page: http://www.cgs.synth.net/
> > > > > > >Yahoo! Groups Links
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > __________________________________________________________
> > > > > > Ken Stone sasami@ otherunicorn@
> > > > > > Modular Synth PCBs for sale
> > > > > > Australian Miniature Horses & Ponies
> > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > > --
> > > ________________
> > > rico loverde
> > > 415.596.6255
> > > ricoloverde.com
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > > ------------------------------------
> > >
> > > The CGS Modular Synth home page: http://www.cgs.synth.net/
> > > Yahoo! Groups Links
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>