So I attempted to rock my new Sea Urchin before I boxed it and got nothing. No sound. Ok, I knew my solder job on this thing was sub-par so I figured I'd start by inspecting the board and wicking up and solder bridges that were out of place and reflowing any suspect joints. After that... SOUND. But no delay. I have a signal going through the thing but no effect no matter how much I play with the pots.
I painstakingly tested every single resistor before I put them in to make sure they were the correct ones. I did not have a way to test the caps so I just put them in but I was careful to get the right values in the right spots. I double checked to make sure the electrolytic caps had the right polarity.
I socketed the ICs and the VR and lined them up according to the diagram (and I remembered the jumper underneath).
I may need some help with this.
Here are pictures of both sides of the board for your perusal. Yes, the solder side looks like a mess (two thumbs up for solder mask) but I looked at everything under the magnifier and I can't see any more solder bridges or bad joints with my novice eyes. Any ideas?
(http://imageshack.us/a/img21/4027/opturchintop.jpg) (http://imageshack.us/photo/my-images/21/opturchintop.jpg/)
(http://imageshack.us/a/img824/2295/opturchinbot.jpg) (http://imageshack.us/photo/my-images/824/opturchinbot.jpg/)
Take voltages. You should have half supply on the 9-16 side of the chip.
If you have that, it's time to pull out the audio probe, schematic, and the datasheet. Start poking around and see where you're losing signal in the delay chip.
Don't just rely on your eyes to tell you if you have a solder bridge, even if you have a magnifying glass. Test for continuity with your multimeter.
If you are absolutely sure there are no bridges,try connecting pins 3 and 4 of the 2399 chip together. I just read the extra projects forum under the sea urchin and it was suggested on page 12
Quote from: midwayfair on May 30, 2013, 07:48:52 PM
Take voltages. You should have half supply on the 9-16 side of the chip.
If you have that, it's time to pull out the audio probe, schematic, and the datasheet. Start poking around and see where you're losing signal in the delay chip.
Don't just rely on your eyes to tell you if you have a solder bridge, even if you have a magnifying glass. Test for continuity with your multimeter.
I will try those things. I might need more detail on the "half supply" bit. I THINK I know what you mean but I'm not sure.
And DUH, use the meter not just my eyes! I feel like a mutton head to not have thought of that myself. I'll do that too.
First, I have to go change a flat tire in the hail storm. Yay.
Ok. Here's a revolting development. I plugged in to my test box to start taking some voltage readings except the power supply I grabbed to plug into was + tip. Immediately after I plugged in, R7 started smoking.
Any predictions on what I wrecked?
I took some voltage measurements in case they mean something to someone. (They don't to me.) Here's what I have:
DC In - 10.86
IC1- pins 1, 2, 3, 5, 6, and 7 all measure about 5.2v. Pin 4 is .01v and pin 8 is 10.4v
IC2- pins 9-16 are all about 5.2v. Pin 1 is 5v, pin 2 is 2.5v, pin 3 is .01v, pin 4 is .11v, pin 5 is 2.77, pin 6 is 2.5, pin 7 is .3v and pin 8 is .75v.
7805- Pin 1 is 5v, pin 2 is .01v, pin 3 is 10.4v
D1- banded end is 10.4v, non-banded end is .01v
I can measure other stuff if it helps figure something out but I don't know what to measure.
Your DC in is too high,what type of power supply are you using? if you can find the data sheets for your IC's that will tell you voltages,if anything is fried,it'd be the IC's also is that a cap socketed or a transistor. If it's a transistor, you may need to replace that also.
Quote from: jimilee on June 01, 2013, 02:05:51 AM
Your DC in is too high,what type of power supply are you using? if you can find the data sheets for your IC's that will tell you voltages,if anything is fried,it'd be the IC's also is that a cap socketed or a transistor. If it's a transistor, you may need to replace that also.
I just grabbed a radio shack wall wart when I logged the voltages (hence having the polarity reversed and frying my resistor). I usually plug it in to my pedal board which (I think) has a superior power supply but it's on the floor in my basement and I didn't want to work there. I'll have to check that supply voltage.
The socket is my voltage regulator. I plugged it in again after smoking my resistor and still got the same result... sound through but no delay. I also retested all the resistors and double checked all the capacitors for values and polarity and they're all correct (and R7 is a little blackened but still measures the correct resistance). I'll see what I can find for specs on the ICs.
Quote from: das234 on June 01, 2013, 02:21:43 AM
Quote from: jimilee on June 01, 2013, 02:05:51 AM
Your DC in is too high,what type of power supply are you using? if you can find the data sheets for your IC's that will tell you voltages,if anything is fried,it'd be the IC's also is that a cap socketed or a transistor. If it's a transistor, you may need to replace that also.
I just grabbed a radio shack wall wart when I logged the voltages (hence having the polarity reversed and frying my resistor). I usually plug it in to my pedal board which (I think) has a superior power supply but it's on the floor in my basement and I didn't want to work there. I'll have to check that supply voltage.
The socket is my voltage regulator. I plugged it in again after smoking my resistor and still got the same result... sound through but no delay. I also retested all the resistors and double checked all the capacitors for values and polarity and they're all correct (and R7 is a little blackened but still measures the correct resistance). I'll see what I can find for specs on the ICs.
Have you jumpered pins 3 and 4 yet?
I did not try the 3-4 jumper yet. I will do that immediately (if not sooner).
We have a winner... jimilee. Jumper from 3-4 on the PT2399 made her echo echo echo echo echo... Thanks.
Is that something that needs to be done on every 2399 or what?
Quote from: das234 on June 01, 2013, 01:49:28 PM
We have a winner... jimilee. Jumper from 3-4 on the PT2399 made her echo echo echo echo echo... Thanks.
Is that something that needs to be done on every 2399 or what?
Nope, not every one. I don't know what the issue is really. I was reading the forums on that build and it was suggested.
It makes sense that they should be connected. Pins 3 and 4 are the analog and digital grounds respectively. They need to be tied together at a point where there is a large mass of ground material. But, in the schematic, pin 4 is tied to the back side of the delay setting resistor network that comes off of pin 6, the VCO pin. That point should go to analog ground as well. I'm guessing that this works in situations where the pot is attached to ground through the box or something like that. In cases where pin 4 and pin 1 of the delay pot don't have any path to ground, it seems like it wouldn't work.