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Messages - zgrav

#31
VFE Projects / VFE Bumblebee troubleshooting
November 21, 2019, 03:30:42 PM
Finished assembling this pedal and now troubleshooting an odd problem.  It is a split-rail design, and when powered I am only seeing -1.2 volts on the negative supply.  If I disconnect the negative power going to the main board, the output from the charge pump is OK on both the positive and negative outputs.  What I then see is that I am getting about 3.5 volts on the negative power traces on the main board with all of the transistors and the two ICs removed from their sockets.  Also getting the same 3.5 v on the negative circuit path when the transistors and ICs are in place.  I am looking for unwanted solder bridges but have not yet found any.  Since that is about 5.4 volts less than the positive voltage going in to the main board, does the voltage reading itself suggest any particular places or parts to check on the board?
#32
Does the trimmer adjustment for the nom nom change the effect you are describing?   And can you hear a difference using the second trimmer to adjust the feedback?  I would try playing with those some more to see if you can get a better overall sound to your liking. 
#33
Global Annoucements / Re: New Projects Are Up!
September 27, 2019, 03:43:12 PM
Mine is apprently in the mail, so no problem here.  But good to know that a few other folks won't be disappointed.
#34
maybe the octave is a feature instead of a concern... : ^ )
#35
Global Annoucements / Re: New Projects Are Up!
September 25, 2019, 06:44:07 PM
No surprise to see that the Snarkdoodle boards are gone.  : ^)   
#36
Global Annoucements / Re: Next giveaway coming soon!
September 09, 2019, 04:32:03 PM
nice to see the build doc posted!
#37
Global Annoucements / Re: Restocks are in.
August 30, 2019, 01:52:56 PM
Enjoy the holiday weekend with your family!
#38
cross your fingers and see if it works after you replace the regulator. 
#39
VFE Projects / Re: Klein Bottle - Makeup Gain Trimpots
August 14, 2019, 07:11:50 PM
Not THAT'S a capacitor...
#40
I put the beveled ring on the outside of the enclosure and another plastic ring on the inside.
#41
sometimes you can get a pop if there is a dc voltage on the ouptut.  you can try replacing the out wire from the PCB to the footwswitch with an electro cap.  maybe 47 UF or higher.
#42
A nice surprise to see the VFE Bumblebee listed as a new project.  I wonder if this is the first of several limited returns of older VFE pedals for MBP.
#43
Sorry to hear about this heartbreaking loss.   Hope you and your family can find some comfort moving forward.
#44
Tech Help - Projects Page / Re: Uber tuber issue
June 18, 2019, 03:22:09 PM
I built the Uber Tuber and my Sat control works but it is subtle.  Running a hotter signal to the input helps.
#45
Interesting that you have built two of these and ended up with the same problem.  In general, these builds for the smaller cases are tougher than larger enclosures.  Have you used your DMM to check for shorts between the wires going to and from the header board?
For starters, you might want to clean some of the flux residue off of you PCB using rubbing alcohol or some other type of electronic cleaner.

The I would use an audio probe to find out how far your audio signal is going through the PCB, starting at the input and checking the audio in and out for all of the points on the ICs. 

When you find the spot where the audio stops use your DMM to make sure your parts connect as shown in your circuit diagram, take voltage readings on the ICs, check ground connections, etc.