sea urchin - houston we have delay! :)

[gtangas]

Hi Guys

Happy new year to all.

So i received today my pt2399 and jump on the delay! yeaaaaa

First time no sound just static and some delay noise on the background... but no guitar signal

checked the pcb and find a bridge...

after solving that issue put it all together again and.... guitar signal but no delay!!

I´m using a 22k pot on the mix because i only have at the moment 2x50k pots! But i think that sould not be the problem!

voltages on the ics:
PT2399
1: 4,94
2: 2,36
3: 1,7mv
4:0,11
5: 2,86
6: 2, 38
7: 0,26
8: 0,79
9: 2,39
10: 2,38
11: 2,38
12: 2,38
13: 2,38
14: 2,38
15: 2,38
16: 2,38

on the Tl
1:3
2:3,02 (some hum when  probing)
3:3
4:1mv
5:6v
6:3
7:3,02 ( some hum when  probing)
8:3

As i told the first time i turn it on i had no guitar signal but mixing with the pots i can ear some delay changes on the static sound... but after i solved the bridge i mix the pots and nothing. just the guitar signal

I changed with a new pt and i have the same result

any ideas? a fault pt? bridge caused some damage on some components?

[jkokura]

You definitely have issues. The TL072 should have 9V on pin 8, 0V on pin4, and about 4.5V on pins 1-3 and 5-7. Sorting out why you have 6V on your ground should be the first thing you do.

Jacob

[midwayfair]

Looks like you probed the pins wrong on the TL072. They go like this:

1    8
2    7
3    6
4    5

It looks like you have 6v on pin 8, which looks like a low battery. All your other pins are reading half that, which is good.

Try a fresh bettery or use a power supply and see if you get sound.

[gtangas]

the regulator is an L7805cv
1: 4,96
2: 1,8mv
3:6,05

[gtangas]

Looks like you probed the pins wrong on the TL072. They go like this:

1    8
2    7
3    6
4    5

It looks like you have 6v on pin 8, which looks like a low battery. All your other pins are reading half that, which is good.

Try a fresh bettery or use a power supply and see if you get sound.

ok this is correct reading

1: 3        8:6
2: 3        7:3
3: 3        6:3
4: 1mv    5:3

the battery that i´m using on this moment as 8v

[midwayfair]

Verify that R7 is 33R, not 33K.

Double check that R20 and R21 are both 10K.

Verify the orientation of D1.

There are a limited number of things between your voltage source and pin8. Get that right first.

Pictures would help. Audio probing will as well. Figure out where you're losing signal.

[gtangas]

i will check the things you point.

I have sound but a clean sound... no delay.

[gtr2]

try jumping pins 3 and 4 together on the pt2399 and then power up the pedal

If I had a dollar for every sea urchin that fixed I'd be a few dollars richer 

[gtangas]

i´m checking all components  

the c16 indicated by MB build list is a 47pf and the one that i have on the board as the inscription 472k

i checked on a conversion tab and this should be an 470k to get the 47pf.. and not the 472k

i´m thinking right?

[gtangas]

i used this chart

http://www.turretboards.com/capacitor_conversion_chart.htm

acording to this:

MB C16 value
uf: 0.000047   pf: 47     nf: 0.047    k: 470K

My C16
uf: 0.0047      pf: 4700   nf: 4.7      k: 472K

[jtn191]

try jumping pins 3 and 4 together on the pt2399 and then power up the pedal

If I had a dollar for every sea urchin that fixed I'd be a few dollars richer 

try this, but also unplug your power first. For me, it only worked when there wasn't power going to the IC to begin with

[gtangas]

one doubt: jumper the 3 and 4 pin and leave it like that forever? Solder a jumper?

and what about the c16?

[gtr2]

one doubt: jumper the 3 and 4 pin and leave it like that forever? Solder a jumper?

and what about the c16?

yes if that solves the problem

[midwayfair]

i´m checking all components  

the c16 indicated by MB build list is a 47pf and the one that i have on the board as the inscription 472k

i checked on a conversion tab and this should be an 470k to get the 47pf.. and not the 472k

i´m thinking right?

Re C16
472 = 4.7nF. You're correct that 47 (or 470) will be 47pF.

That's something that should be fixed, because it's going to significantly darken your tone, but it will not cause you to lose signal to the delay. If you check the schematic, you'll see that the delay is tapped from the output of the first half of the op amp; the clean signal moves on to the output buffer, and the delay does its thing and is mixed back in.

If you are truly getting amplified signal from your op amp, then your problem lies somewhere in the PT2399 section of the pedal. Jumper the grounds first (Josh has lots of experience with these and it's a good suggestion!); reflow your solder points, and get out the audio probe to figure out where the signal is being lost. The audio probe is your best friend at this point.

[mysticaxe]

I had the exact same problem with my Sea Urchin.  Delay worked intermittently.  When it didn't, I noticed ~1.4V on pin 4.  I jumpered pins 3 and 4 and the problem was solved.