# Obsidius Preamp .. no working attack and drive



## Iampaul (Mar 19, 2020)

*Obsidius Preamp.. Attack Toggle and Drive not working*

1) Attack Toggle when select do not hear any change
2) Drive Pot must be turn to max and got little distortion.
3) Ouput Level is very low

IC4.1, 4.2.. when check the signal just only half c16 680pf


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## music6000 (Mar 19, 2020)

Iampaul said:


> *Obsidius Preamp.. Attack Toggle and Drive not working*
> 
> 1) Attack Toggle when select do not hear any change
> 2) Drive Pot must be turn to max and got little distortion.
> ...


What happens to the Level & Distortion when you adjust the Blend pot?





						Obsidius Preamp Level Pot
					

Hello! I'm just wrapping up building this pedal, and so far I think it sounds great. It's amazing the range of tones you can get out of it. I did notice something strange, and I'm wondering if I screwed something up or if it's the way it's designed. The level pot only seems to adjust the volume...



					forum.pedalpcb.com
				




There's a lot of components, Did you use 1/8 Watt resistors, jamming 1/4 Watt resistors is asking for Trouble?
* Need: *Post Good Pictures of Front & Back.
 Where & What J201's did you use.


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## Vildhjuggah (Mar 19, 2020)

When i built mine i had a bunch of problems. Including a couple of wrong capacitors and one of the capacitors didn't have a solid connection and when i would push the capacitor i figured out that seemed to be the main thing that was making the sound not working right. I think it was the 220nf cap on the left that was loose. hope that helps! Cuz i wasted a lot of mine and chucks time (sorry chuck) checking the transistors and random shit, when it was mostly a loose capacitor.


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## Iampaul (Mar 19, 2020)

Vildhjuggah said:


> When i built mine i had a bunch of problems. Including a couple of wrong capacitors and one of the capacitors didn't have a solid connection and when i would push the capacitor i figured out that seemed to be the main thing that was making the sound not working right. I think it was the 220nf cap on the left that was loose. hope that helps! Cuz i wasted a lot of mine and chucks time (sorry chuck) checking the transistors and random shit, when it was mostly a loose capacitor.



I will check again per your advise.  Thank you


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## Iampaul (Mar 19, 2020)

music6000 said:


> What happens to the Level & Distortion when you adjust the Blend pot?
> 
> 
> 
> ...



I will picture next week.  I already on the road trip.  I used 2n5457 instead of J201 because unable to bough it.  I got the signal before and after Jfet. Thank you for your advise


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## Iampaul (Mar 20, 2020)

music6000 said:


> What happens to the Level & Distortion when you adjust the Blend pot?
> 
> 
> 
> ...





music6000 said:


> What happens to the Level & Distortion when you adjust the Blend pot?
> 
> 
> 
> ...



1) When adjust blend pot to Max.   Level is very low output and Distortion is little distortion and low output
2) I use 2n5457 instead of J201 due to unable to find here
3) IC at bottom of right hand, low signal at pin 3,2 and pin 6,7 also same


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## Vildhjuggah (Mar 21, 2020)

quoting chuck from his first response to my post
"1) Read the other posts in this forum.
2) Clean your board with IPA & a toothbrush.
3) Perform a thorough visual inspection of all components and solder joints. Use good lighting and magnification.
3a) For examples of bad solder joints, look at the pix in this forum.
3b) For examples of good solder joints, look at the pix in the Build Reports forum.
4) Reflow / resolder only the joints that look bad. You can resolder a joint only so many times before the traces start to lift or the parts get damaged.
5) If it still doesn't work, post detailed photos here.
6) Make sure you have a DMM, even if it's one of the Harbor Freight freebies. And an audio probe. "

then follow his instructions to me starting on page 2






						Obsidius preamp problems
					

When you're ready, get your delay going with a more-or-less constant tone. Connect that to the input of you Obsidius. Connect the Audio Probe's ground clip to the ground lug on the IN or OUT jack. Power up the Obsidius. Set the BLEND to 0 (dry), DRIVE to 0 and LEVEL to noon. Set your amp's...



					forum.pedalpcb.com


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## music6000 (Mar 21, 2020)

Iampaul said:


> 1) When adjust blend pot to Max.   Level is very low output and Distortion is little distortion and low output
> 2) I use 2n5457 instead of J201 due to unable to find here
> 3) IC at bottom of right hand, low signal at pin 3,2 and pin 6,7 also same


I was going to suggest Cleaning the board with Isopryl & toothbrush or Electronic Cleaner Spray.
Did you wait between Soldering each Toggle pad, ie Solder One, Miss One & wait 20 seconds
With the Attack Switch in Middle* Off *position, are you getting signal with DMM on continuity setting to Attack Switch outer Pads?
If you are, the Switch is Fryed!
They look like they had a lot of Heat & Solder.

As for finding other Faults, Click on *Vildhjuggah *link above.

Good Luck


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