rebote 2 debug help please

[makaze808]

Hi. I have built a rebote 2 and allas it isn't working. The dry signal is passing through to the output but no wet ones.
I have checked the voltages and they appear normal. I built an audio probe as suggested here and found that on pin 15  on the pt chip there is the delayed repeats.

I am having trouble working out how to follow the signal to locate the problem, i just get lost and dont see how they could get to the output. the repeats get to lug 2+3 on the repeat pot and lug 2 on the level pot. Can someone direct me from pin 15 or reverse from the output to identify the cause.

Help is gratefully received.

[makaze808]

Sorry forgot the schematic.  http://www.tonepad.com/getFile.asp?id=50

[Auke Haarsma]

Just follow the signal and see where it gets lost.

Good that you have probed the signal at Pin 15.

Now check the signal at the Wiper of the Repeats pot.
If you have no signal, check for shorts with at the parts from pin 15 to the Wiper.

If you do have signal: good! Continue and check for signal at the Wiper of the Wet-pot.
If you have no signal, check for shorts with at the parts from Repeats pot to the Wet pot.

Now, if there is also signal at the Wetpot, continue to IC2. Check for signal at Pin 2 and Pin 1.


Also, you mentioned you checked the voltages. Please post all voltages on the PT2399, IC2 and the 5V regulator. This helps spotting the problem.

[makaze808]

Thanks, will post.

[Renegadrian]

Don't want to start a topic with the same title (keep the forum clean)

I made a Vero layout for the Rebote 2, starting from the Tonepad file.

Sad to say...It doesn't work...It just gives out a bad hum...No signal at pin 15.

Voltages.

power jack   9.60
7805 in        9.60
7805 out      5.05

TL072
1                  9.00
2                  7.80
3                  7.45
4                  8.08
5                  7.55
6                  7.55
7                  9.00
8                  9.60

PT2399
1                  5.05
2                  2.49
3                  0
4                  0
5                  1.87
6                  2.49
7                  4.26
8                  3.60
9                  2.52
10                2.49
11                2.49
12                2.49
13                2.49
14                2.49
15                2.49
16                2.49

The only "mod" (should give "trails") is the momentary lack of the 15k res on top left (1st and 2nd row), now jumpered.
The res below should be the "infinite" res - I just put in the standard 15k.

Any clues?!

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EDIT - I just deleted my layout - don't want to go against anyone's will...

[MikeH]

IIRC, a while back fp asked people not to post vero layouts of the rebote.  Sorry to be a stick in the mud.

[Auke Haarsma]

check for a short around pin4 of the tl072. It should be at 0V.

And, if I recall correctly, pins 1-3 and 5-7 should be around 4,5 V. Something wrong around the LT072.

[Renegadrian]

check for a short around pin4 of the tl072. It should be at 0V.

And, if I recall correctly, pins 1-3 and 5-7 should be around 4,5 V. Something wrong around the LT072.

Auke, thx for the input - I made my layout from FP schematic, there's no indication about pin 4 - while I can clearly see in the PCB that pin 4 goes to ground - mine was connected to nothing! This will be the first correction tomorrow...Also I'll recheck the layout with both PCB layout and schem. I'll try to see if some other errors can be sorted out.
---------------------------------
Another error found - as a break in a track was missing, the voltage divider was in the same row connected with the input - now they share the track but are divided as they should be by that track cut...

[Renegadrian]

All right, I just corrected those two errors I made in my layout, but still my rebote 2 wasn't working correctly.
I had this mod I read in the byoc forum (the byoc DD is known to be the same circuit) which was meant to give "trails" by putting one of the 15k res on a switch (and it's not the "infinite" mod).
You can read about it here http://www.buildyourownclone.com/board/viewtopic.php?f=20&t=6410&st=0&sk=t&sd=a

I just put that res. in (and not jumpered as I had before) so building it stock, and voila', instant delay!!! I love this circuit, thanks again to FP.
I'll keep the vero layout I made for myself...
I just managed to put it inside a 1590B, as my layout is not as square as the original, but it follows the enclosure in a horizontal way. Pics will follow soon.