PT-80 Delay troubleshooting

Started by soohyun2222, January 10, 2013, 03:43:34 AM

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soohyun2222

Hi guys,
I have a trouble with my PT-80. Its PCB is a DIY, and I think I did a good job on that.

I have done some voltage checking, and I am pasting the results.
Any help is appreciated!!

TL072 IC: pin#, actual voltage [need to be] (units in V)
IC Pin 1: 1.33 [6]
IC Pin 2: 1.57 [6]
IC Pin 3: 2.22 [6]
IC Pin 4: 0.00

  • IC Pin 5: 0.77 [5.5]
    IC Pin 6: 0.76 [6]
    IC Pin 7: 0.71 [6]
    IC Pin 8: 0.70 [12]

    PT2399 IC:
    IC Pin 1: 6.32 [5]
    IC Pin 2: 2.51 [2.5]
    IC Pin 3: 0.04 [0.015]
    IC Pin 4: 0.04 [0.015]
    IC Pin 5: 2.93 [2.8]
    IC Pin 6: 2.50 [2.5]
    IC Pin 7: 3.26 [0.9]
    IC Pin 8: 3.27 [0.9]
    IC Pin 9: 0.42 [2.5]
    IC Pin 10: 0.11 [2.5]
    IC Pin 11: 4.71 [2.5]
    IC Pin 12: 2.51 [2.5]
    IC Pin 13: 0.29 [2.5]
    IC Pin 14: 2.51 [2.5]
    IC Pin 15: 2.51 [2.5]
    IC Pin 16: 0.26 [2.5]

    NE 571 IC:
    IC Pin 1: 0.92
    IC Pin 2: 1.84
    IC Pin 3: 1.84
    IC Pin 4: 0.02
    IC Pin 5: 1.15 [1.8]
    IC Pin 6: 9.62 [6.5]
    IC Pin 7: 9.60 [6.5]
    IC Pin 8: 1.84
    IC Pin 9: 1.84
    IC Pin 10: 6.04
    IC Pin 11: 1.84
    IC Pin 12: 1.84
    IC Pin 13: 10.16 [12.0]
    IC Pin 14: 1.84
    IC Pin 15: 1.84
    IC Pin 16:

    5v regulator
    Base: 4.97
    Collector: 0.03
    Emitter: 11.93

    12V regulator
    Base: 10.03
    Collector: 0.03
    Emitter: 11.36

Marcvv

#1
What is the problem you are having?

How are you powering this? It seems that your power input is too low to start with. The PT 80 needs 15 volt at minimum if you are using it with the 12 volt regulator as you are and you are not using a charge pump.

Pin 1 of your PT 2399 should have around the same voltage as your 5 volt regulator and that is of in the readings you are giving. So that is an indicator: Did you check al your soldering, no solder bridges or bad solder points?
Did you check and re-check al the component values?

soohyun2222

Thank you for the interest
I am powering this pedal with a 9 volt battery that has not been used other than for this delay pedal.
I did some troubleshooting already and now the voltage reading of the battery was about 8.8v. I read somewhere that above 8.7V is fair.
Anyhow. I thought I was using charge pump. I followed the instruction with the charge pump.
I recently got 9v DC converter, but I am afraid of electroshock and have been delaying using it to power my pedals.

I will recheck the wiring line between my 5V regulator and PT 2399 's.
You know, solder bridges,,, they are tricky to check. The board is populated and sometimes my wires are bent and they touch each other. Any suggestions?
Other than IC I did not check the component values. unsolder one of the sides and check it with the voltmeter right?

Once again thanks!

Quote from: Marcvv on January 10, 2013, 04:10:36 AM
What is the problem you are having?

How are you powering this? It seems that your power input is too low to start with. The PT 80 needs 15 volt at minimum if you are using it with the 12 volt regulator as you are and you are not using a charge pump.

Pin 1 of your PT 2399 should have around the same voltage as your 5 volt regulator and that is of in the readings you are giving. So that is an indicator: Did you check al your soldering, no solder bridges or bad solder points?
Did you check and re-check al the component values?

Marcvv

#3
You still have not told what is not working?
Sure the voltages are off but is any signal passing?

Go to http://www.diystompboxes.com/wiki/index.php?title=Debugging and read about debugging.

Yes, checking solder bridges can be difficult. Look closely and keep checking. Check for cold solder joints. Reflow your solder connections. No wiring of components should be touching eachother as you describe. Post some pics of your build if you can.

What is the charge pump you are using?

The PT80 is not an easy build, so be patient and keep checking.

soohyun2222

#4
Hi, its me again.
I am still working on the pt80 delay from generalguitargadgets.com
Here are my voltage readings as of now.

MAX1044 IC: pin#, actual voltage [need to be] (units in V)
working fine

PT2399 IC:
IC Pin 1: 4.988 [5]
IC Pin 2: 2.461 [2.5]
IC Pin 3: 0.031 [0.015] *
IC Pin 4: 0.031 [0.015] *
IC Pin 5: 2.848 [2.8]
IC Pin 6: 2.467 [2.5]
IC Pin 7: 0.8 (fluctuates) [0.9] *
IC Pin 8: 0.8 (fluctuates) [0.9] *
IC Pin 9: 2.469 [2.5]
IC Pin 10: 2.471 [2.5]
IC Pin 11: 4.473 [2.5]
IC Pin 12: 2.476 [2.5]
IC Pin 13: 2.469 [2.5]
IC Pin 14: 2.463 [2.5]
IC Pin 15: 2.472 [2.5]
IC Pin 16: 2.472 [2.5]

NE 571 IC:
IC Pin 1: 0.758 [1]
IC Pin 2: 1.843 [1.8]
IC Pin 3: 1.843 [1.8]
IC Pin 4: 0.012 [0.003] *
IC Pin 5: 1.165 [1.8] *
IC Pin 6: 11.51 [6.5] *
IC Pin 7: 11.51 [6.5] *
IC Pin 8: 1.844 [1.8]
IC Pin 9: 1.844 [1.8]
IC Pin 10: 6.083 [6.0]
IC Pin 11: 1.842 [1.8]
IC Pin 12: 1.846 [1.8]
IC Pin 13: 12.12 [12.0]
IC Pin 14: 1.844 [1.8]
IC Pin 15: 1.844 [1.8]
IC Pin 16: 1.263 [1.0] *

12v regulator
Base: 12.12
Collector: 0.03
Emitter: 16.37
5V regulator
Base: 4.988
Collector: 0.03
Emitter: 16.37

There is no audio signal comming out from the pedal when it is turned on.

PRR

> NE 571 IC:
> IC Pin 6: 11.51 [6.5]
> IC Pin 7: 11.51 [6.5]


Why?

You have not said what specific PLAN you are working from.

You have not said how it SOUNDS.
  • SUPPORTER

soohyun2222

Thank you everyone,
I changed the NE571 chip and here are the new readings:
NE 571 IC:
IC Pin 1: 0.762 [1] *
IC Pin 2: 1.828 [1.8]
IC Pin 3: 1.828 [1.8]
IC Pin 4: 0.006 [0.003]
IC Pin 5: 1.830 [1.8]
IC Pin 6: 5.515 [6.5] *
IC Pin 7: 5.515 [6.5] *
IC Pin 8: 1.844 [1.8]
IC Pin 9: 1.844 [1.8]
IC Pin 10: 6.112 [6.0]
IC Pin 11: 1.825 [1.8]
IC Pin 12: 1.830 [1.8]
IC Pin 13: 12.12 [12.0]
IC Pin 14: 1.828 [1.8]
IC Pin 15: 1.829 [1.8]
IC Pin 16: 1.229 [1.0]

I should add that the delay is working now. It does what I want it to do.
Best wishes,
Kevin