So I have an odd issue. My Sea Urchin works for about 10 minutes, then loses all delay, and won't work anymore. I initially thought it was an LM7805 issue, so I changed it out, as well as changing out the PT2399, but no dice. Any ideas?
Hmmmmm any pictures? And have you double checked all of the values on your board?
I know I had a sunking that would work for 2 mins then go caput because of some wrong values.
(http://dl.dropbox.com/u/34971369/2012-02-16%2017.48.04.jpg)
Well first, I would add a PT2399 chip.......... ;D
I am on the road this weekend so I can't offer any more advice on this layout. Is this the one from Josh?
Why are you using an LM3508?
I don't know where I got htat number from. It's an LM7805.
Have you checked to make sure it's putting out 5v? Also, try powering it up and check it continuously for about 2-3 minutes with your DMM to see if the voltage is draining somehow.
Where did you get you pt2399's from. I had a lock up problem with a batch off ebay.
Josh
Quote from: gtr2 on February 26, 2012, 12:58:30 PM
Where did you get you pt2399's from. I had a lock up problem with a batch off ebay.
Josh
It would seem that's not the case here since it's not locking up when powered on. Or, did you have a similar experience with the bad batch?
Oops I didn't see the 10 min part. Mine were locking up on power up.
Josh
Quote from: gtr2 on February 26, 2012, 11:57:19 PM
Oops I didn't see the 10 min part. Mine were locking up on power up.
Josh
You can actually design something around that if you use an LM317 instead of the regular 7805. The datasheet has a little circuit for a slow warm up....I think that might take care of the lockup problem. I've tested it out, but not on a PT2399. It's really similar to the anti-lockup circuit from the Little Angel, except in that case it doesn't control the regulator but the VCO pin of the PT2399. Obviously, that way works really well, too!
I checked the voltages with the DMM, and I'm getting 5.1 VDC into pin 1 of the 2399. Just to make sure, when I check the voltages, I can ground out the ground lead anywhere, i.e. on the case, right?
Also, my LM7805 is getting warm to the touch. Is that normal?
Here's the pin readings for the 2399.
1: 5.1
2. 2.54
3. 0
4. 0.17
5. 3.02
6. 2.55
7. 4.4
8. 0
9. 2.55
10. 2.55
11. 2.54
12. 2.55
13. 2.53
14. 2.53
15. 2.54
16. 2.55
TL072
1. 3.26
2. 3.26
3. 3.26
4. 0
5. 3.26
6. 3.26
7. 3.26
8. 6.52
Quote from: gtr2 on February 26, 2012, 12:58:30 PM
Where did you get you pt2399's from. I had a lock up problem with a batch off ebay.
Josh
I got them from Tayda. I've used 3 separate PT2399s all with the same symptom..
The TL072 is problematic. Your supply voltage on pin8 is only 6v. It should be 9v.
I'm going to swap it out for a 4558. Let me get back to you in a sec. Thanks, Brian
I'm stil only reading 6.8 with the 4558.
voltage on the 1n4001 is reading 6.6. Could it be the 33R resistor, or the diode?
Are you sure you did not use a 3k3 resistor? Or higher? The bands should be orange-orange-black.
the resistor bands are orange orange black gold brown. The DMM, set at 200 ohms, is reading 33.4.
I think it might be a bad resistor. But would this explain the delay not working after a few minutes? If it was a bad resistor from the get go, and I'm not getting enough voltage, wouldn't it not work at all?
Then again, if it was a bad resistor, my DmM wouldn't show 33.3, would it?
Take the resistor out and put a jumper in its place to see if that solves the problem. If you are running the effect on a well regulated power supply or battery it's superfluous, anyway. And it that does not solve it, then it could be somewhere else down the line in the supply chain.
I jumpered the 33R, and now the LM7805 is getting massively hot. Can't figure out what's going on now.
I have a 330R, is that too much to try and sub the 33R with?
It was the 33R. I replaced it with a 100R, now it's working fine. Thanks again, Brian.
I've been away for a couple days...
glad to see you got it working :)
Josh