First of all, thanks for this amazing pedal. I just finishing soldering and the overall assembly process for pedalSHIELD following all the instructions and I managed to upload a couple of effects to the unit but I don't seem to be able to hear them. The led lights up when I reset or load an effect. Also, I get the true bypass but when I hit the footswitch the DSP does not work and the signal is blocked. Is there any way to troubleshoot the unit, I am not expert solder but I was very careful and checked that all parts where correctly in place. What would be most likely an issue that can lead to what's happening to me? What parts are really sensible? Any help on this would be appreciated.
I figure out what was happening and the unit does work BUT the output sound level is far to low so I had to crank everything up to hear any effect. That is all pots are to the max, the trimmer resistance is set to max (saturating the DAC) and the volumen of my amplifier is set to max, and it is Fender frontman 25R which is pretty loud under normal circumstances. Having done that the tremolo effect is pretty nice .
I tried to troubleshoot my unit and replaced all three chips with other spare parts but that did not work. I assume that might have to do with some faulty part at the output stage that is affecting the bias point of the operational amps but I am not sure. I got all my parts from mouse electronics using the Bill of Material for the SHIELD all but the 1uF caps that were sold-out. I got mine from amazon: (Panasonic ECE-A1HKA010 Capacitor, Alum Electrolytic; Cap 1 uF; Tol 20%; Vol-Rtg 50 VDC; Radial; 4x7; Bulk)
I will look into the the Kicad schematics but later since I have to download kicad and I need to learn how to use. So far, I have measured all pin voltage and the only thing that seems unusual is that Vin ~ 4.37v and 3.3v ~ 3.19v, I am using an ipod charger connected to one of the micro usb ports as you recommended. Also these are the measured nonzero (~ 0V) voltage values I recorded:
Hi,
The pedal works quite straight forward, but I know that sometimes we can miss small things.
Sounds obvious but my first advice is to check all the solder joints, dead shorts, switched parts, capacitors/diodes in the wrong position, op amps in the tc1044 socket... take the picture in the building manual and verify that all is the same.
You can check that the output stage is right by loading the sinusoidal generator program. It only uses the output stage, so you should have a clean tone at the output.
JR,
Thanks for quick reply and all the suggestions. I did check that all parts were in the right place several times and the sine wave gen program does work, the output signal again is not well amplified. Now, I am pretty convinced it is cold joint and I did triy adding more solder to some joints that didnt look good. That didnt work either. In fact, now the pedal is not even bypassing the clean signal. I have been looking online and some people use calibrated ovens to fix cold joints and I have access to one. I will keep on trying and hopefully next time I will have better new to tell. Thanks again!
As with the Tremolo effect the sine wave output is not well amplified, also I can change the tone and gain with pedalSHIELD knobs as supposed to. However, in order to hear an audible sound output from pedalSHIELD (no matter what effect) I must crank up my amplifier's gain up to max. I believe I must have a cold joint in output stage or in the foot switch, or some part is not working properly. I have been busy with other projects but I am planing to use a calibrated oven to reflow the solder and fix any cold joints. I am uncertain if this is the right way to proceed but I can't think of anything better. Any feedback would be appreciated.
Usually when I build pedalSHIELDs they work straight away, but there is always the human factor, so placing parts in the wrong position or place is the most common problem.
Cold joints could be also possible but at least for me it does not happen so often.
As I mentioned before, you can try playing the sine wave program, if it works it is because all the output stage is fine and you can focus in the input stage.
If you have an oscilloscope you can try injecting a sinewave into the pedal (there are plenty of smart phone applications for doing that) and measuring with the probes as the signal pass trough all the stages...
The orientation of the DIP8 sockets does not matter, as you said the orientation of the ICs over them is the important.
However I advice you not to do it, cause in 1 month time you will probably forget about it and if some body else (or even you) play with the board or change the ICs, there will be a lot of confusion.
I guess that you are asking it because you already soldered them, dont worry, dont bother to de-solder them, just put some kind of mark with tipp-ex (or something similar)on the right side and will be enough.
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