SOLVED Dark Rift repeats are pretty short

dstahl

New member
I am starting a new thread for this since I resolved the previous issue. The effected sound is pretty clean now, but I am not getting the amount of repeats that I think I should. I get like 3 repeats before they trail off. And I can't get anywhere near self-oscillation.
I tried swapping pt2399 again to no avail.
The B50k pot seems to behave just like the other pots when measured with a DMM

any thoughts on what to try?

 

zgrav

Well-known member
Nice job cleaning your board. Did you use IPA and a toothbrush?
Double check the values on R10 (1K) and R8 (18K). Your repeat pot works, but it seems like you are losing some signal in the repeat path.
 

dstahl

New member
Nice job cleaning your board. Did you use IPA and a toothbrush?
Double check the values on R10 (1K) and R8 (18K). Your repeat pot works, but it seems like you are losing some signal in the repeat path.
I have something called "Heavy Duty Flux Cleaner" spray. It is super toxic, but does the job well.
I re-checked those values and they do measure out correctly for R8 18K and R10 1k.

Does anyone have any ideas if there is any easy way to rule out the pot being the issue? When measuring any 2 lugs next to each other, I can see resistance change as I move the pot. I do see one side maxing out at 40k and the other at 50k. But I would think even if it didn't get full 50k it still wouldn't cut off repeats like that. But I am only guessing.
 

zgrav

Well-known member
are you measuring the resistance or going by the colors on the bands? check your resistance on the repeats pot between terminals 1 and 3 to see if it is 50K. then make sure when the repeats are maxed that you are getting very little if any resistance between the middle terminal and one of the outside terminals, and see what the resistance is between terminal 2 and ground at that point (should be close to 50K)
 

dstahl

New member
I first measured and double checked with DMM and then I also verified colors for R10 were Brown,Black,Black,Brown,Brown. which should be 1k with 1% tolerance.
Term 1&3 = 48.7
Term 1&3 maxed out = 41.3
Term 2&ground maxed out = 41.25
 

dstahl

New member
Ok. I think I got it.
C7 was 1u. But when measuring it, it looked kind of wonky fluctuating readings. I wasn't sure if that was because it was in circuit at the time of measurement. But I replaced with another 1u MLCC and on testing it was doing repeats properly. So either it was a bad component or the pads needed to be reflowed extra well.
Thanks for everyones help here
 
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