What is the correct diode?

Started by FastEdTex, August 04, 2016, 12:01:57 PM

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FastEdTex

Quote from: FastEdTex on August 08, 2016, 01:00:53 AM
Quote from: Groovenut on August 08, 2016, 12:14:26 AM
Quote from: FastEdTex on August 07, 2016, 10:49:21 PM
Quote from: Groovenut on August 07, 2016, 10:15:39 PM
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.  :icon_redface:

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.

Well, nothing changes with any of 4 TL072's in the as IC1 or IC2.
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

Groovenut

Quote from: FastEdTex on August 09, 2016, 09:50:43 AM

Well, nothing changes with any of 4 TL072's in the as IC1 or IC2.
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
Voltages on IC3 look reasonable, IC1 find out what is causing pin3 and pin7 to be low (they should be V+/2), IC2 is really wonky. The only negative voltage should be pin 4. Pin 1, 6, 7 and 8 should all be positive voltages. (1, 6, and 7 V+/2, 8 V+*2-diode drop*2).

I'd suggest looking for a short from a trace linking to pin5 on IC3 or thereabouts.
You've got to love obsolete technology.....

FastEdTex

Voltages on IC3 look reasonable, IC1 find out what is causing pin3 and pin7 to be low (they should be V+/2), IC2 is really wonky. The only negative voltage should be pin 4. Pin 1, 6, 7 and 8 should all be positive voltages. (1, 6, and 7 V+/2, 8 V+*2-diode drop*2).

I'd suggest looking for a short from a trace linking to pin5 on IC3 or thereabouts.
[/quote]

OK, I'm still a newbie to all this so are you saying a short in the PCB as in a damaged trace line?
A badly soldered component? Cold joint, solder bridge?

I've seen in my google searching some folks use a cleaner to clean the PCB after soldering to remove flux residue. I know now why you would do that as it is impossible to see the trace lines as the PCB's solder mask in black. Should I invest in a cleaner of some kind?

Groovenut

Quote from: FastEdTex on August 09, 2016, 08:41:12 PM
OK, I'm still a newbie to all this so are you saying a short in the PCB as in a damaged trace line?
A badly soldered component? Cold joint, solder bridge?

Yes check all the above

Quote from: FastEdTex on August 09, 2016, 08:41:12 PM
I've seen in my google searching some folks use a cleaner to clean the PCB after soldering to remove flux residue. I know now why you would do that as it is impossible to see the trace lines as the PCB's solder mask in black. Should I invest in a cleaner of some kind?
I've had good luck with plain old isopropyl rubbing alcohol and a toothbrush
You've got to love obsolete technology.....

FastEdTex


Yes check all the above

Quote from: FastEdTex on August 09, 2016, 08:41:12 PM
I've seen in my google searching some folks use a cleaner to clean the PCB after soldering to remove flux residue. I know now why you would do that as it is impossible to see the trace lines as the PCB's solder mask in black. Should I invest in a cleaner of some kind?
I've had good luck with plain old isopropyl rubbing alcohol and a toothbrush
[/quote]

Well, I'm looking and not having any luck, but that is a rare thing...luck.
I am determined to complete this project.

FastEdTex

#25
Re-worked the entire board. New reading below.
Have not wired the switch or jacks or Pots just testing V's at the IC's
New Battery for testing at 9.34 V

IC1                IC2               IC3
1 = 4.60        1 = 4.69       1 = 9.32
2 = 4.60        2 = 4.69       2 = 4.80
3 = 4.01        3 = 4.60       3 = 0.00
4 = 0.00        4 = -8.90      4 = -4.29
5 = 4.54        5 = 4.64       5 = -8.84
6 = 3.29        6 = 4.69       6 = 4.41
7 = 3.37        7 = 3.37       7 = 4.15
8 = 9.33        8 = 17.00     8 = 9.31

I'm not saying it... but it has a pulse.

AION numbers
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

Quote from: FastEdTex on August 11, 2016, 12:21:13 AM
Re-worked the entire board. New reading below.
Have not wired the switch or jacks or Pots just testing V's at the IC's
New Battery for testing at 9.34 V

IC1                IC2               IC3
1 = 4.60        1 = 4.69       1 = 9.32
2 = 4.60        2 = 4.69       2 = 4.80
3 = 4.01        3 = 4.60       3 = 0.00
4 = 0.00        4 = -8.90      4 = -4.29
5 = 4.54        5 = 4.64       5 = -8.84
6 = 3.29        6 = 4.69       6 = 4.41
7 = 3.37        7 = 3.37       7 = 4.15
8 = 9.33        8 = 17.00     8 = 9.31

I'm not saying it... but it has a pulse.
Those numbers look much better
You've got to love obsolete technology.....

FastEdTex

Quote from: Groovenut on August 11, 2016, 10:19:42 AM
Quote from: FastEdTex on August 11, 2016, 12:21:13 AM
Re-worked the entire board. New reading below.
Have not wired the switch or jacks or Pots just testing V's at the IC's
New Battery for testing at 9.34 V

IC1                IC2               IC3
1 = 4.60        1 = 4.69       1 = 9.32
2 = 4.60        2 = 4.69       2 = 4.80
3 = 4.01        3 = 4.60       3 = 0.00
4 = 0.00        4 = -8.90      4 = -4.29
5 = 4.54        5 = 4.64       5 = -8.84
6 = 3.29        6 = 4.69       6 = 4.41
7 = 3.37        7 = 3.37       7 = 4.15
8 = 9.33        8 = 17.00     8 = 9.31

I'm not saying it... but it has a pulse.
Those numbers look much better

So I wired it up and now it is not working so well.
IC1
pin 4 is reading 3.4 V and should be ground or 0
pin 8 is reading 4.06 V and should be 9 V

Other 2 ICs are reading very close to spec.

NO Sound - bypass or effect.

FastEdTex

Groovenut

Thanks for all your help.

4 months later, in the box and working. I"m slow, but I get there.