shecho good sound but no echo ?????

[bent]

hi,
i build the shecho, the sound go throught and come out clean but it did not do any echo at all..nothing..nada... 

i tcheck my soldering and every thing is fine...
i have build one already and it's working fine, so i check voltage on both off them and everything look the same, so i try to swap all ic from the working board to this one, and no effect.... sound is clean but like no effect at all...
here's the data:

ht8955a:
1- 1.96                           
2- 1.96
3- 1.96
4- 1.96
5- 0
6- 1.51
7- 1.67
8- 1.49
9- 1.58
10- 0
11- 1.86 <-> 2.84
12- 1.42 <-> 3.45
13- 2.33 <-> 2.47
14- 2.30 <-> 2.46
15- 2.36 <-> 2.45
16- 2.46
17- 2.46
18- 2.46
19- 1.65
20- 2.47
21- 2.62
22- 0.84 <-> 1.02
23- 3.28
24- 4.95

41256:
1- 0.83 <-> 1.03
2- 2.66
3- 2.46
4- 1.65
5- 2.46
6- 2.46
7- 2.46
8- 4.91
9- 1.43 <-> 3.47
10- 2.33 <-> 2.46
11- 2.36 <-> 2.46
12- 2.36 <-> 2.46
13- 2.0 <-> 2.8
14- 2.65
15- 3.28
16- 0

sa571:
1- 0.92
2- 1.79
3- 1.79
4- 0
5- 1.79
6- 6.56
7- 6.56
8- 1.79
9- 1.79
10- 7.97
11- 1.2
12- 1.2
13- 8.57
14- 1.79
15- 1.79
16- 0.76

tl072:
1- 4.75
2- 4.25
3- 4.24
4- 0
5- 3.86
6- 4.25
7- 4.25
8- 8.55

7805:      (|
1- 8.67
2- 0
3- 4.96

2n5088:   (|
1- 8.36
2- 3.68
3- 3.08

any help will be appreciate....

thank's 

bent

[bent]

hummmm..... no chance so far..... 

[Dean Hazelwanter]

Hi,

Make an audio probe (as per instructions on GEO), and check for signal at the following points:

- U2 pin 11
- R7 and C29
- U4 pin 4
- U2 pin 2
- U2 pin 6, 7
- Wiper of 'Delay Level' pot

Check back, and we'll get this sorted out.

[bent]

thank's Dean for the help, and sorry for the late reply, i was out of home during week-end...

ok, so i have a audio probe and do the test you ask me....
u2 pin 11 -> guitar signal
r7 and c29 -> no sound and 1.96 v
u4 pin 4 -> no sound...
u2 pin 2 -> no sound...
u2 pin 6/7 -> no sound...
wiper delay -> no sound...

seem's like the signal do not come out right from the sa571.... ?

bent

[Dean Hazelwanter]

Ok, since you have no signal at the R7-C29 junction, check at U2 pin 10. If you don't have a signal there, then U2 is not being setup right - or else U2 is bad. But, since the same 571 chip works in your other board, U2 must be good. So, check the circuitry around U2A for bad solder joints, solder bridges, broken or shorted traces, wrong component values etc. Now you know where the problem is, we just have to figure out why. 

[bent]

i'll try to verify everything ASAP.... my problem is i'm leaving on honeymoon in 2 days, and my wife is....hum....hysterical  
cause we have to prepared everything , and if i play with my stompbox...she turn a little  .... hahaha   

i'll keep in touch...

bent 

[Mark Hammer]

If I had to choose between repeats of my guitar signal, and repeats of what happened on my honeymoon, I think I know what I'd choose.

Vaya con dios, buddy!  Your soldering iron isn't going anywhere.

[bent]

Your soldering iron isn't going anywhere.

LOL   

i think i'll use my "other soldering iron"...     

Vaya con dios, buddy! 

thank's Mark  ......SUN...here i come... 

bent

[bent]

ok... i have a few minutes to verify the board  and find out a error i made  , i didn't make a point connection at the cross line of:    sa571 pin 10 - c8 1uf      and      c31 1uf - r6 36k

now it's made... i have a little echo very far in the sound  , and i have a anoying ultra-sound (Hiiiiiiiiiiii) that follow the LFO(?) of the echo...

i continued when possible (only have tonight before leaving tomorrow) to verify and find error...but Dean if you have a idea...

thank you very much....

bent

[Dean Hazelwanter]

What are you building this on - vero, perf, or the pcb layout found at GGG?

You said you had another working unit - can you go through them point by point through the signal chain to see where things go goofy?

By the way, with your honeymoon approaching, you should be chowing down on oysters and other aphrodesiacs, instead of working on stompboxes!

[bent]

i'm back.... wow what a great vacation...lot's of fun 

i get back to debug the echo, and find C9 was reverse ... put it back right, now i have a SMALL echo, about 2 repeat ( volume about 5/10 and 2/10 of the original hit) with all pot at max... and after 10-15 seconds, no more echo... i change all the IC one by one with test in between and nothing change...BTW to get back the small echo , each time i have to put IN-OUT to ground for few seconds before replug...

What are you building this on - vero, perf, or the pcb layout found at GGG?

PCB that i made from GGG schematic....

You said you had another working unit - can you go through them point by point through the signal chain to see where things go goofy?

did it, and so far, when i loose the sound is normally at pin6 and 7 of sa571, i change the sa571 with the one of my working one, same thing happen that i mention previously.....

By the way, with your honeymoon approaching, you should be chowing down on oysters and other aphrodesiacs, instead of working on stompboxes!

don't worry, when i don't do stompbox, i debug my wife 

Dean... like Obewan said , you're my only hope....

Bent

[Dean Hazelwanter]

Ok, try disconnecting the 'Repeats' pot (P1), both the 'top' (connected to C16 and P2) and the wiper connection. You should have exactly 1 repeat. How does it sound? Does it keep working for more than the 10-15 seconds?

What happens if you wait more than the 10-15 seconds before playing the first note? Does that 1st note get delayed correctly, and then after an additional 10-15 seconds it stops working?

[RDV]

I had a similar problem with my PT-80 build. In my case I had mixed up some .01uF and .1uF caps and all I could hear was a faint echo. I went through the parts list very intently with the PCB in hand and figured it out.

I still have trouble with the Millenium bypass on it but have not fixed that part yet as I only use it at home.

Regards

RDV

[bent]

Ok, try disconnecting the 'Repeats' pot (P1), both the 'top' (connected to C16 and P2) and the wiper connection. You should have exactly 1 repeat. How does it sound? Does it keep working for more than the 10-15 seconds?

1 repeat at volume 5/10, then after +/- 15 seconds, ....  bye bye echo.... no more...

What happens if you wait more than the 10-15 seconds before playing the first note? Does that 1st note get delayed correctly,

without the repeat pot... yes...volume 5/10

and then after an additional 10-15 seconds it stops working?

don't know why, sometime it take 15 seconds, sometime 60 seconds or more....

i will do some other test later this evening, have to eat , and take care of the kids....so i'll get back this evening with other result..

bent

[bent]

ok, back to debug...BTW thank you very much Dean for the time you give me...

I had a similar problem with my PT-80 build. In my case I had mixed up some .01uF and .1uF caps and all I could hear was a faint echo. I went through the parts list very intently with the PCB in hand and figured it out.

thank's RDV for the reminder...i verify EVERY parts value...and guess what i put a 0.1 instead of 0.001 in C12    ... now echo is back as normal...well almost  .... it's make a echo, and i can control with the 3 pot  ....but the echo have some sort of static or harsh in it and keep getting worst as time past , and i'm loosing repeats untill i have nothing...( inside about 90 seconds)

i change every IC and 7805/2n5088 , clean the board from flux, redo every soldering, and it's still doing it...

i try to play a note, wait 15 seconds, play a note, wait 15 seconds, ect...it's the same has a play without stop...

the only thing different between the working board and this one, C3- C6- C15- C19 are mica instead of ceramic disc...every other parts are the same.....

BTW, i still have a "Hiiiiiiiiiiiiiiiiiiiii" back in the sound , and like a "tic....tic.....tic.....tic.....tic" that goes faster or lower when i play with the 500k pot.....

I'll be back on the debug thursday evening around 22h30 ... now it's 03h15 am.... and my pillow is calling....

good night everyone...

bent

[bent]

well i wont be able to debug tonight cause my work call and it's missing someone, so i have to go to work...debug in minimum 1 week....

i'm thinking maybe to build another, since i redo lots of thing on this one i might overheat something...

bent

[Dean Hazelwanter]

BTW thank you very much Dean for the time you give me

No problem, I just wish I could do more - it's kinda tough doing this remotely.

BTW, i still have a "Hiiiiiiiiiiiiiiiiiiiii" back in the sound , and like a "tic....tic.....tic.....tic.....tic" that goes faster or lower when i play with the 500k pot.

Silly question time. R27 is a 4.7 ohm resistor, right? You have C21 on the back side of the board (or under the IC socket) for decoupling the supply for U3 right?

It might be worthwhile to do another board, with new components for 2 reasons.
- If you are concerned that you might have overheated something, you might have.
- It sounds like the 'wrong value component' bug has bitten you a couple of times, and this will give you a chance to start fresh, and double check the value of every component you install.

[bent]

ok... a did another board and verify every value before soldering...and guest what...
same problem  exactly the same problem....

so a check every trace on the pcb with the original schematic and find out a error... on the schematic of the PDF from GGG you see that R22 is on the pin 8 of HT8955A and goes to pin1 of P-3 and then pin2/3 of P-3 goes to pin 9 of Ht8955A... but on the page 3 where you see all the parts on the board, R22 is on pin9 of HT8955A and goes to P-3 then return to pin 8 of HT8955A.... that's not a big thing...
but my error is that i mixt both thing and put R22 on the same side of pin2/3 of P-3 and pin1 goes directly to HT8955A  ...why is it affecting like that- i dont know  , but the thing is that now that it is connected like it's supposed - R22 on pin 1 of P-3 and pin 2/3 to HT8955A...
echo is working perfectly...

except for the "hiiiiiiii" but that probably come from the thing that i reduce to maximum the board and finish with a pcb of 2.75 inch X 2.75 inch .... inteference on the circuit... but i can arrange that....

so now i have 3 echo board working..... 

thank's Dean for the patience and the help, we finally did it....
and it's a great echo BTW....

Bent