Zero Point Dual Delay Help

[eshelton]

yeah, all 3 are socketed. voltages are in an earlier post.

[jimilee]

Yeah I saw the voltages. It sounds as if there is a hardware problem somewhere. I had an issue with a pin being bent on an ic socket of the zpsdx. This problem is most perplexing for sure.

[eshelton]

Resistor band values are all correct.  IC socket pins all appear to be coming through the board and soldered in place.  Should I try taking them out and soldering the ICs directly to the board?  But would the voltages show up apparently correct if there were a problem with the socket? 

I'm going to do some extensive and methodological probing and voltage testing and I will post my results.   

[jimilee]

I'm not sure At this point but you have voltages so tht wouldn't be necessary. If midwayfair or scruffie or josh could have a look and see what's next, that'd be cool.

[eshelton]

Ok, here is the result of some audio probing.  Blue dots are a good signal.  Pink R's are radio reception. No dot means nothing is coming through there.  And I have already mentioned the very weak signal after C3. 

[jkokura]

Checking C3, R6 and the out for partial bridges, or for bad joints would be good. Replacing C3 might also help.

Jacob

[eshelton]

Thanks, I've checked those pads for bridges and reflowed with no luck.  I don't have a replacement for c3 laying around, but I will replace it as a last resort...I'd just have to make a trip up to the electronics store tomorrow probably.  Any ideas that would explain all the dead pads and radio interference on the right side of the board?

[jimilee]

Thanks, I've checked those pads for bridges and reflowed with no luck.  I don't have a replacement for c3 laying around, but I will replace it as a last resort...I'd just have to make a trip up to the electronics store tomorrow probably.  Any ideas that would explain all the dead pads and radio interference on the right side of the board?

Usually radio interference is a lack of ground somewhere.

[eshelton]

It wouldn't have anything to do with leaving out r30, would it? That's what was recommended in the build guide. Maybe need to jumper or something to connect that ground pad? Idk.

[jimilee]

It wouldn't have anything to do with leaving out r30, would it? That's what was recommended in the build guide. Maybe need to jumper or something to connect that ground pad? Idk.

Nope, that's for delay times, no need to socket it.

[jimilee]

Do you get any sound if you remove the 2399's (IC2 and 3)? Have you any others to put in their place? I experienced this with the neptune delay I built. You can get bad ones from time to time. I got a bad one from mouser ironically. I really think this a bad part issue.Your soldering looks great from what i can see,flowed through the hole and everything.

[eshelton]

Took out the 2399s and I'm still getting signal at c3 and very very low signal at output.  When the ICs are out, though, the quality of the sound is different.  I don't hear the echo--just clean signal.  I don't have anything to swap in for them.

I just got a new soldering station that I'm really pleased with, so I was super confident with my connections. Lol...that's the way it goes, I guess.

[3petedt]

for my two cents, I think there is something wrong with Q1/Q2 voltage.
both E legs go to ground and should not have any reading (I think), where Q2 reads 0.06
Q1 - 2.36, .63, 0
Q2 - 2.37, .63, .06
Given the sensitivity of trannies (and the option to experiment), I socket ALL transistors.  From your pictures, it appears that Q1/2 and the 78L are directly soldered to the board. 
I will defer to the wisdom of the moderator(s), as this is more an observation.
I am building the ZPSDX and am trolling similar builds on the lookout for possible build problems and the experience of others. 

[eshelton]

Well...Still no joy.  I replaced both of the 2399s and get the same problem. I will take a look again at my transistors.  I don't remember if i mentioned it somewhere earlier in this thread, but removing the sockets and soldering the transistors direct to the board was one of the first fixes I tried because they didn't feel secure in the sockets.

[RobA]

I'm just looking at the thread for the first time and trying to follow everything you've done so far, so sorry if I ask any redundant questions. Have you checked if there is continuity between the output and ground by using the continuity setting on your meter? What transistors did you use?

If I read what you've said right, you've got at least some signal up to the output cap and then it's dead at that point. The resistor on the output is in the right range, so that shouldn't be the problem. It seems that it either has to be the output cap is bad or you are shorting to ground somewhere after the cap (in the jack or footswitch or at the board). Do you have a voltage reading for the output pad?