Sea Urchin power problem

[bangerang101]

I'm having a problem w/ this build...

It will work perfectly normal for a while, then when I bypass the switch, pull out the power adapter and plug it back in, and switch it back on, it wont get a delay signal, just a clean signal and it will stay 'not working' until I unplug it again, and leave it for about 5 minutes, then plug it back in... don't understand what it could be, as Ive never ran into this problem before...

Ive checked for pinout problems (namely the voltage regulator), solder joints, and wiring issues. I also know that it's not the 3pdt switch failing because it did it on my breadboard as well.

Is it possible that its a bad/faulty voltage regulator?

[sprayfe]

Where'd ya get your pt2399?

[gtr2]

Sounds like a possible intermittent/cold solder joint.  Check your voltage on the pt2399 when your not getting delay.

[bangerang101]

I got it from Tayda electronics... Is that a bad source for those... are all pt2399's not the same? The markings on it say PTC (brand?) pt2399(type), then a bunch of other numbers on it...

not sure, but heres the voltages I'm getting on ic pins when it's working vs. not working:

Working
--------
Pt2399          
1 - 5.08          
2 - 2.54
3 - .01
4 - .11
5 - 2.53
6 - 2.55
7 - .14
8 - .81
9 - 2.55
10 - 2.55
11 - 2.55
12 - 2.55
13 - 2.55
14 - 2.55
15 - 2.55
16 - 2.55
Tl072
1 - 4.29
2 - 4.29
3 - 4.27
4 - .01
5 - 4.26
6 - 4.29
7 - 4.29
8 - 8.56
L7805
1 (In) - 8.56
2 (Gnd) - .01
3 (Out) - 5.08

Not working
------------
Pt2399
1 - 5.08
2 - 2.54
3 - .02
4 - 1.91
5 - 5.06
6 - 2.55
7 - .08
8 - 4.68
9 - 4.88
10 - .80
11 - 2.55
12 - 2.55
13 - 2.55
14 - 2.55
15 - 2.55
16 - 2.55
Tl072
1 - 3.39
2 - 3.39
3 - 3.37
4 - .02
5 - 3.37
6 - 3.39
7 - 3.39
8 - 6.76
l7805
1 (In) - 6.77
2 (Gnd) - .01
3 (Out) - 5.08

So you can see the voltages seem to be a bit off when it's not working. Also, it doesn't always not work after unplugging it the first time... it will work for a couple 'power cycles' sometimes, then randomly stop working. Any suggestions/help?

[gtr2]

I don't see anything wrong with that at first glance based on what your describing.

Do you have an audio probe.  I'd start checking in the signal path going to and from the pt2399.  From what other have said there where some bad 2399's from Tayda, but I thought they had a "motorboating" problem.

Josh

[bangerang101]

Yeah, that was the next step I was going to take... I just wanted to see if anyone had ever had this or a similar problem before.

It wouldn't be an intermittent connection I don't think, because it's not intermittent when your playing it (when it's working), or if I move the board and wiring around or whatever....it's just when you uplug and plug the power adapter back in it just completely stops working. Thanks for the suggestions, btw, keep em coming!

[madbean]

It sounds like pin6 is shorting to ground directly on power up. That would cause the PT to latch up and then need resetting.

Check to see if R18 is actually 2k7. If so, you might have just a bad chip.

[bangerang101]

Ok, I was checking the signal w/ the audio probe while the pedal was not working and I just felt the delay chip w/ my finger, and it was really warm to the touch. So I continued to probe around a little anyway, and found that I'm not getting signal anywhere on the delay chip pins except for pin 15 (lpf1-out). Also, when the pedal is "on" I still get output signal out of the circuit, but the signal is just not delayed.

So, my theory is that the delay chip is working for a set amount of time, then overheats and stops working once it's overheated. Now I just need to figure out why. Could this be from a wrong connection somewhere? or a bad solder joint? Or would this more likely be that the chip is just bad/faulty, or is there more of a chance of the 5v regulator being bad/faulty? IDK, I'm going to take out the delay chip and put a socket in and try another one (I just so happened to order 2, thank God) and see what happens.  

[bangerang101]

Yeah, unfortunetly it was a 2.7k... so I guess I'll definitely change out the delay chip. Don't know what else to do at this point anyway. Thanks for all your guys help, again, and I'll post what happens after I change the delay chip.

[lloyd17]

It's your 2399's dude. All my chips from Tayda have the same issue in the urchin [lock ups] and echo base [noise noise noise] Replaced the chips with smallbear stuff and they work perfectly.

[bangerang101]

Yeah... I just swapped it out and put in a different one (also from tayda), and it did the same thing: Works flawlessly until I unplug it (adapter) then plug it back in... When I plug it back in, I get no delay signal, just clean signal when on, and the delay chip starts feeling hot to the touch... but everything else seems perfectly fine on the board and I had no problems putting it together. I guess I should have looked into these delay chips first before purchasing them. I just had no idea there could be that big of a difference between two different brands of the same exact chip. Anyway, I guess I'll have to order some $20 (not literally) ones from small bear, lol.

[gtr2]

Has anyone contacted Tayda about the bad pt2399's?

[bangerang101]

    Yeah, I did. I explained to them that I ordered a couple of them and they were all bad/faulty and they simply said, "sorry about the problem your having w/ the pt2399's. Send us the receipt and well refund you the money.", lol, but didn't explain anything about why there messed up, or if they all are, or anything.

    So IDK, I guess just don't order those PT2399's from Tayda until you hear otherwise... I'm not going to anyway.

[bangerang101]

I received my pt2399 from mammoth electronics today (it was a little cheaper to get a single chip than from smallbear), and just wanted to confirm it was the bad/faulty pt2399's from tayda causing the problem.

The delay works flawlessly now (except the switch pops, only the first time on??, anyone ever had this problem?) and actually, I think the repeats even sound a little cleaner/hi-fi w/ the new chip in. What a great delay pedal for how simple and cheap it is to build! Thanks for the help guys, and heed my warning! DONT USE THE PT2399's FROM TAYDA ELECTRONICS (at least for now, anyway).

[lloyd17]

Mine had a really bad pop on the 3pdt as well. Adding a 1m pulldown on the output cured that right up.