Rebote 2.5 stopped working

[jeff g]

I built a Rebote 2.5 several years ago and it recently stopped working.  I've been debugging, but I've taken a fairly long break from building so I'm pretty rusty and looking for some help.  here's the details:

Name:  Rebote 2.5
The layout is at http://tonepad.com/getFile.asp?id=98

Modifications or subsitutions: no
Followed the pcb layout: yes

Positive ground circuit: no

What it does:  I am running off battery power supply. I have a clean signal when bypassed but no guitar signal when the unit is turned on.  LED lights when switched.


My voltages are as follows: 

Battery= 8.15
9V+ at circuit board=8.15 
Voltage at end of black battery lead=0
PT2399
1. .8
2. .4
3. 0
4. 0
5. 0
6. 0
7. 0
8. 0
9. 0
10. 0
11. 0
12. 0
13. 0
14. 0
15. 0
16. 0

IC TL072

1. 0.1
2. 0.3
3. 8.15
4. 4.06
5. 0.1
6. 0
7. 0.1
8. 4.06

IC L78L05

In  .6
Gnd 0
Out 8.15


I know there are voltage issues, I'm not sure how to resolve them.

thanks

[pappasmurfsharem]

I assume your regulator blew it should only output 5v I think. Which probably fried your pt2399 hense all the 0s on nearly all pins

After rereading.  you might have the in and the out of the regulator labeled backwards.  But one should definitely be ~5v

[jeff g]

I assume your regulator blew it should only output 5v I think. Which probably fried your pt2399 hense all the 0s on nearly all pins

After rereading.  you might have the in and the out of the regulator labeled backwards.  But one should definitely be ~5v

thanks for the quick reply - you are correct.

I put in new regulator and PT2399.  now I get voltages on the IC, but still no output.

new voltages:

battery=9.54
9v at board=9.33

PT2399

1=0.8
2=0.55
3=0.55
4=3.75
5=0.42
6-0.64
7=9.33
8=4.62
9=4.62
10=.52
11=0.58
12=4.62
13=0
14=0.58

[pappasmurfsharem]

I got nothing now smarter minds will be along shortly.

I'd say audio probe around to see where your signal dies.

[jeff g]

thanks.  Audio probe was next on my list.  Just have to either find mine or make a new one and remember how to use it!

[pinkjimiphoton]

if you run a rebote on a battery, you're asking for trouble. once the battery gets below about 6 volts, your 7805 will get damaged. if it slides below 5 volts, it will kill it dead. it will overheat and smoke. and when it does, it smokes the 2399 most of the time in my experience, cuz the voltage either goes up (as in your case... new chip time) or goes open, and you get nothing.

i discovered this running a rebote 1 on battery. sounded AWESOME... a lot of cool modulation... as the battery died, but once it died completely, it smoked the whole dang thing.

there's a video of it on my youtube.com/666pinkster i think i called the video rebote weirdness or something similar.

[jeff g]

thanks, I didn't realize that.  i have only used adapters - battery was just for testing because I found the wallwarts were above 9v.

[jeff g]

just in case anyone has the same problem and is searching .....

i managed to get this going with some audio probing.

I'm not sure why, but all three ICs were fried - replaced them and good to go.

thanks to those who provided help.
jeff