What is the correct diode?

[FastEdTex]

AION project list an IN4742 for Z1

1N4742ATR   1N4742A   1N4742A_T50A   1N4742A-TR   1N4742A TR   1N4742A,113   1N4742A-TAP   1N4742A-TP   1N4742A,133

I find all these on Mouser with that part number, sizes are slightly different, all are DO-41   save one DO-41G
The difference i notice is the Zener Current
21 mA     21 mA        21 mA               76 mA             380 mA                 76 mA               76 mA                76 mA            76 mA
2 are 1.3 W and the rest are 1 W

How can I know which one?

[FastEdTex]

And....

Mfr.'s Part #:                 TL072IP     TL072CP   TL072IPE4   TL072CPE4
Vos - Input Offset Voltage:   6 mV       10 mV      6 mV       10 mV

Project AION Refractor
https://aionelectronics.com/wp-content/uploads/2013/11/aion-refractor-centaur-documentation-v2.pdf

I installed the TL072IP, should it have been the CP or CPE4?

Still having problems getting it to work so I'm checking all the components to verify they are correct values and orientation on the PCB.

[TejfolvonDanone]

Are you sure about those Zener currents?
Maximum current is calculated as Iz = Pz/Uz. So if you have a 1W Zener with 12V Zener voltage it can cunduct about 83mA and 108mA for the 1.3W.
If you reverse the 380mA you get Pz = 5W. That's really suspicious.

The "A" clearly denotes that it has a 5% tolerance in the Zener voltage.

The datasheets say a lot of types of currents.
For example:
http://www.jameco.com/Jameco/Products/ProdDS/1538081.pdf
It says that the diode we are talking about has a 9 Ohm resistance at 21mA current and 700 Ohm at 0.5 mA. Also it can withstand a 380mA surge current for 8.3msec. Be careful with datasheets that they always say the most appealing aspects of a certain part.

Without any knowledge of the circuit i can't say anything for sure but i'd say all of them can be good if none of the conducts more than the maximum current allowed.

[TejfolvonDanone]

Still having problems getting it to work so I'm checking all the components to verify they are correct values and orientation on the PCB.

If you can't get this work don't be bugged down on little details like this. These are so little differences between those that a circuit's working can't depend on them.
Check the forum for basic debugging procedure: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[J0K3RX]

In that schematic it just prevents polarity inversion in the power supply circuit.

[FastEdTex]

Thanks for the input!

I will post all the voltage readings on all 3 ICs and 4 diodes, 1 Zenner, to see if I can get some help.
I'm checking all the components as I am new to this and have no formal training in electronics so I know enough to be dangerous.
I think I may have a incorrect value on one of the capacitors and possible 1 incorrect Resistor.

[FastEdTex]

Thanks for the input!

I will post all the voltage readings on all 3 ICs and 4 diodes, 1 Zenner, to see if I can get some help.
I'm checking all the components as I am new to this and have no formal training in electronics so I know enough to be dangerous.
I think I may have a incorrect value on one of the capacitors and possible 1 incorrect Resistor.

Well I will get to posting the V's -  I did find 2 components, 1 resistor and 1 cap that are the wrong values.
No sense going any further until Mr. Dyslectic gets the decimal in the right place.

[FastEdTex]

And....

Mfr.'s Part #:                 TL072IP     TL072CP   TL072IPE4   TL072CPE4
Vos - Input Offset Voltage:   6 mV       10 mV      6 mV       10 mV

Project AION Refractor
https://aionelectronics.com/wp-content/uploads/2013/11/aion-refractor-centaur-documentation-v2.pdf

I installed the TL072IP, should it have been the CP or CPE4?

Still having problems getting it to work so I'm checking all the components to verify they are correct values and orientation on the PCB.

+9V = 9.03 (battery)

IC1  TC1044SCPA
1 = 9.02
2 = 3.72
3 = 3.72
4 = 0.00
5 = 0.00
6 = 4.05
7 = 3.90
8 = 9.00
IC2   TL072
1 = 1.15
2 = 3.26
3 = 6.32
4 = 0.17
5 = 6.31
6 = 1.08
7 = 1.12
8 = .057
IC3  TL072
1 = 9.08
2 = 0.11
3 = 0.00
4 = 0.83
5 = 0.17
6 = 0.18
7 = 0.90
8 = 9.05
D1 and D2 = NO Voltage (can't be good)
D3 = 9.00/8.64
D4 = 8.63/8.28
Z1 = 8.90

I have tested with amp and guitar and bypass has no output/sound.
Effect on has no sound until I turn the volume all the way down and hear a quite "pop" then turn it back up and I have sound but no overdrive.
Link to the docs in the quote above.
I also check R13 and have no voltage at either end of the resistor so I'm guessing that is why there is no voltage at D1 and D2.
There is 4.30 v at the + side of C9 and 0v at the other which goes to R13, and it goes to D1 and D2 then to SW2-1 that is the effect output.
Not and trained engineer, just trying to figure this thing out.

[FastEdTex]

[PRR]

> D1 and D2 = NO Voltage (can't be good)

This is normal. No DC voltage here.

The standout problem is IC1 should be making a Negative 9V, at pin 5, and doesn't seem to be doing that. Someone who knows TC1044 may spot the problem. As the -9V supports the whole back-end of the audio path, you need this to work.

[Groovenut]

According to the schem, pin 3 of the 1044 should be at ground, 0V. As Paul said pin 5 of the 1044 should be -8.4V or so. You have no bias voltage on IC3 and pin 8 of IC2 should be around 18V. There's something that needs sorted with your 1044 chip or it's connections before you can proceed much more. In the pics the polarity of the caps looks good. Have a look at the ground connection of the 1044.

[FastEdTex]

According to the schem, pin 3 of the 1044 should be at ground, 0V. As Paul said pin 5 of the 1044 should be -8.4V or so. You have no bias voltage on IC3 and pin 8 of IC2 should be around 18V. There's something that needs sorted with your 1044 chip or it's connections before you can proceed much more. In the pics the polarity of the caps looks good. Have a look at the ground connection of the 1044.

Well, sometimes pin 3 of the 1044 reads 0V and sometimes it does not.
I re-heated each of the 8 pins on the solder side (with the 1044 out of the socket)
checked them under magnification and did not see problem.
So out of frustration (and ignorance) I checked for continuity of the socket. There is continuity between pin 1 and pin 2 (without the chip). Than can't be right.
I don't see any solder bridge, could it be bad socket?

[Groovenut]

Possibly or there's a connection under the socket on the component side of the pcb. May have to remove the socket to investigate further

[FastEdTex]

Possibly or there's a connection under the socket on the component side of the pcb. May have to remove the socket to investigate further

Removed socket. PCB has continuity between Pad 1 and Pad 2.

[FastEdTex]

Possibly or there's a connection under the socket on the component side of the pcb. May have to remove the socket to investigate further

Removed socket. PCB has continuity between Pad 1 and Pad 2.

Let's just say I found the problem and the enemy is I.

IC3 = 1044
1 = 8.88     8 = 8.88
2 = 5.24     7 = 4.17
3 = 0.00     6 = 4.00
4 = -3.61    5 = -8.83
IC2 = 072
1 = -7.42    8 = -7.88
2 = 3.27     7 = -7.35
3 = 3.94     6 = -7.03
4 = -8.82    5 = 3.92
IC1 072
1 = 3.99     8 = 8.88
2 = 3.98     7 = 1.33
3 = 1.15     6 = 3.78
4 = 0.00     5 = 3.34
Z1 = 8.82
D3 = 13.60
D4 = 14.30

So now the thing works in bypass, I get sound, click the 3PDT and the led lights but no sound.

[FastEdTex]

Possibly or there's a connection under the socket on the component side of the pcb. May have to remove the socket to investigate further

Removed socket. PCB has continuity between Pad 1 and Pad 2.

Let's just say I found the problem and the enemy is I.

IC3 = 1044
1 = 8.88     8 = 8.88
2 = 5.24     7 = 4.17
3 = 0.00     6 = 4.00
4 = -3.61    5 = -8.83
IC2 = 072
1 = -7.42    8 = -7.88
2 = 3.27     7 = -7.35
3 = 3.94     6 = -7.03
4 = -8.82    5 = 3.92
IC1 072
1 = 3.99     8 = 8.88
2 = 3.98     7 = 1.33
3 = 1.15     6 = 3.78
4 = 0.00     5 = 3.34
Z1 = 8.82
D3 = 13.60
D4 = 14.30

So now the thing works in bypass, I get sound, click the 3PDT and the led lights but no sound.

Here are some number from AION from an old post for V at the ICs
My IC3 is close as my battery is down in V output around 8.1 V
IC1 pin 3 and pin 7 are low
IC2 is FUBAR

IC1 - TL072
1 = 4.49
2 = 4.49
3 = 3.54 stable, 3.95 initial (cap charge bleeding down through the meter)
4 = 0.00
5 = 4.49
6 = 4.49
7 = 4.49
8 = 9.00

IC2 - TL072
1 = 4.55
2 = 4.49
3 = 4.49
4 = -8.59
5 = 4.49
6 = 4.49
7 = 4.44
8 = 16.23

IC3 - TC1044SCPA
1 = 9.00
2 = 4.59
3 = 0.00
4 = -4.22
5 = -8.59
6 = 4.09
7 = 5.59
8 = 9.00

[Groovenut]

In the pics you posted, it looks as though you have IC1 and IC3 swapped in the wrong sockets.

[FastEdTex]

In the pics you posted, it looks as though you have IC1 and IC3 swapped in the wrong sockets.

Yes, the enemy is I. I found that mistake and have corrected it.
Question is now they are in the correct place and I have replaced 1 wrong value cap and 1 resistor, have I damaged the IC2? or IC1?
IC3 seems to be working per the numbers from AION.

Also resistors installed are reading:
17 = 13k should be 27k
19 = 11k should be 25k
22 = 53k should be 100k
24 = 53K should be 100k
all around 1/2 what they should be, I'm I using the meter wrong, seams unlikely that they would all be bad?

[Groovenut]

In the pics you posted, it looks as though you have IC1 and IC3 swapped in the wrong sockets.

Yes, the enemy is I. I found that mistake and have corrected it.
Question is now they are in the correct place and I have replaced 1 wrong value cap and 1 resistor, have I damaged the IC2? or IC1?
IC3 seems to be working per the numbers from AION.

Also resistors installed are reading:
17 = 13k should be 27k
19 = 11k should be 25k
22 = 53k should be 100k
24 = 53K should be 100k
all around 1/2 what they should be, I'm I using the meter wrong, seams unlikely that they would all be bad?

If you have other TL072s, I would try them to see if the voltages straighten out.

Did you test the resistors in or out of the circuit? Most of the time to get an accurate reading, the components will need to be removed from the circuit as they can be in parallel with other components and will most likely not return accurate readings.

[FastEdTex]

In the pics you posted, it looks as though you have IC1 and IC3 swapped in the wrong sockets.

Yes, the enemy is I. I found that mistake and have corrected it.
Question is now they are in the correct place and I have replaced 1 wrong value cap and 1 resistor, have I damaged the IC2? or IC1?
IC3 seems to be working per the numbers from AION.

Also resistors installed are reading:
17 = 13k should be 27k
19 = 11k should be 25k
22 = 53k should be 100k
24 = 53K should be 100k
all around 1/2 what they should be, I'm I using the meter wrong, seams unlikely that they would all be bad?

If you have other TL072s, I would try them to see if the voltages straighten out.

Did you test the resistors in or out of the circuit? Most of the time to get an accuarate reading, the conponents will need to be removed from the circuit as they can be in parallel with other components and will most likely not return accurate readings.

I do happen to have 2 more TL072s ordered just in case I need them - I swapped the 2 in the circuit and got the same readings as posted before after placing them in the correct sockets. 

The resistors were still soldered in the circuit. Thanks, I'm so intent on debugging this think and getting it to work that I overlooked the obvious.