Need Help With A New ADA Flanger Problem

[newperson]

Hi,
Thanks for the quick reply.  I cannot find any DC readings close to 15VDC anywhere.  11.4VDC is the highest I can read on the regulator.  Which seems to make since because it has a .12 on the part which is making me think that it is a 12v regulator and not a 15volt one.  Should it be a 15volt part? 

The transformer itself is only putting out 4.5 VDC.

I was going to try to swap out the only trans with the 201 like your above post, but I thought that the power issue might be the problem?
Paul.

[Paul Marossy]

Hi,
Thanks for the quick reply.  I cannot find any DC readings close to 15VDC anywhere.  11.4VDC is the highest I can read on the regulator.  Which seems to make since because it has a .12 on the part which is making me think that it is a 12v regulator and not a 15volt one.  Should it be a 15volt part? 

The transformer itself is only putting out 4.5 VDC.

I was going to try to swap out the only trans with the 201 like your above post, but I thought that the power issue might be the problem?
Paul.

According to the original ADA Flanger documents I have, it should be a 15V voltage regulator.

Some of your readings don't make sense, though. You must have higher than 4.5VDC on the secondary side of your power transformer, or you would never get a reading of 11.4VDC at your regulator. The voltage does sound too low, however. You should have around 15VDC at the voltage regulator...

[newperson]

I am going to swap that part out with a 15volt reg to see about it.  i think the lower voltage reading is because of the ac/dc difference.  Is the power transformer in there just a step down and not an AC/DC converter?  thanks again,

[newperson]

will a
L7815ACV - 15V 1 A Positive St Voltage Regulator
work?

[Paul Marossy]

I am going to swap that part out with a 15volt reg to see about it.  i think the lower voltage reading is because of the ac/dc difference.  Is the power transformer in there just a step down and not an AC/DC converter?  thanks again,

Yes, it is a step down transformer. The secondary AC is full wave rectified via D7, D8, D9 & D10. C31 (and C32 on Rev 4) is the filter cap to smooth out the ripple, followed by IC7 (voltage regulator).

will a
L7815ACV - 15V 1 A Positive St Voltage Regulator
work?

Yes, as long as the pinouts are the same as the original voltage regulator (which I think they are, but please verify that).

[newperson]

I swapped IC7 out and it reads the same voltage.
Here are the IC's.  I cannot read them from the link on page 2 of this thread.  Perhaps your list is cleaner.  Can you confirm?

IC3 - LM324N -8024
IC4 - MC1458M - SA8027
IC1- 4741CP -8037
IC2 - 3403CP -8101
IC5 - 4007UBPC -8101
IC6 - CP40478CN - MM5647BN
IC8 - MM3010
IC7 - LM340.12 78127

Looks like they are from 1980-1981.  I restated my questions below because the thread took on a new page.  I am getting thumps that the speed control knob controls with my audio probe from different areas, but nothing else.

I will take some voltages and post them in a bit.



Hi,
A few questions about this pedal.  I have one that passes clean signal but does not have an effect.  The clean signal gets a bit weaker when the switch is on.  I believe I have Version 4, MN3010 chip.  My first guess is that it seems that the internal transformer has gone bad.  I am looking at the link earlier in the thread to see the layout of the pedal.  The power transformer has 120VAC on side and 4.5V dc on the other side.  From what I can tell it should be 15VDC correct?  Not 15VAC right?  IC7 has 11.4V DC, 0 Volt DC, 10.1 Volt DC, and when measure with AC on the meter 24.3VAC, 0V, 21.5VAC.  I am taking my ground reading from pad A which is connected to the black ground wire from the jacks.  Should this part be putting out 15VDC?  Step on in the calibration test procedure says IC7 Pin 3 +15V.  My IC7 is marked 7812C LM340.12.  So does this make it a LM340 with 12v out?  Is it the wrong part and should be LM340.15?  Or is the power transformer making it have the off reading?

Am I reading this right and need a new power transformer?  If so can someone point me to a part number for this transformer?  I am in the US and mouser or digikey would be a nice place to order from.  If need be I could order a wall wart and wire that.  In that case would I need 15VDC .5 to 1 amp?

I am a little confused on why the AC reads on my meter.  That is my second learning question from this.  Why does the AC read on this part?  Or why can one read AC?

Thanks for any help,
Paul.

[newperson]

i stuck a few pictures up.  might help out to see the board.
http://www.antennastoheaven.com/ADAFlanger.htm

[Paul Marossy]

Looks like you have the Rev 4 circuit board. Here's some more things to try:

Check the AC voltage on the secondary of the transformer (set your meter on AC and measure the outside legs). It think it should be around 12VAC or so to get a high enough voltage to handle the losses thru the voltage regulator and 15VDC to the rest of the circuitry. If that looks to be OK, then...

Check C31 & C32. Maybe one of them is faulty, and it's messing with the voltage from the voltage regulator.

Check diodes D7, D8, D9 & D10 and make sure none of them are faulty.

You might also want to switch out IC-1, IC-2, IC-3 and IC-4 to see if one of those might be bad. I've had another unit where a couple of those chips went bad. You might want to build an audio probe and trace the signal path, it would help you to determine what is wrong.

Your list of IC chips looks right from what I can remember. It's very doubtful that you will be able to find a direct replacement transformer, but you might get lucky. For testing purposes, you could get a wall wart with sufficient voltage & current and see if you have different results with that.

[newperson]

would the wall wart need to be ac or dc 18v?

[newperson]

I cannot find over 10.5 volts anywhere on the board.  the transformer is strange because the 4 pins show 4.7DC or 10.7AC.  C31 I replaced and C32 shows 10.24DC and 21.7AC.  I am not for sure how I should be measuring the voltage on this board yet, AC or DC?  Most of the ICs show about 5VDC.  With my audio probe I can hear what i am guessing to be a LFO ticking mainly around the middle of the board.  I can change the speed with the pot.  I also can hear a higher Vol clean signal around IC3 area. 

I can post a full IC voltage once I know to measure it in DC or not and if not seeing 14VDC anywhere is the main issue.  I don't understand why AC is showing up.  Usually I have only looked at DC. 

If I was to bypass the power transformer with a Wall wart would a 18VDC one be what I need or a 18VAC one?

Thanks again for your help so far.
Paul.

[Paul Marossy]

would the wall wart need to be ac or dc 18v?

If you bypassed the transformer, it would need to be DC.

I cannot find over 10.5 volts anywhere on the board.  the transformer is strange because the 4 pins show 4.7DC or 10.7AC.  C31 I replaced and C32 shows 10.24DC and 21.7AC.  I am not for sure how I should be measuring the voltage on this board yet, AC or DC?  Most of the ICs show about 5VDC.  With my audio probe I can hear what i am guessing to be a LFO ticking mainly around the middle of the board.  I can change the speed with the pot.  I also can hear a higher Vol clean signal around IC3 area. 

I can post a full IC voltage once I know to measure it in DC or not and if not seeing 14VDC anywhere is the main issue.  I don't understand why AC is showing up.  Usually I have only looked at DC. 

If I was to bypass the power transformer with a Wall wart would a 18VDC one be what I need or a 18VAC one?

Thanks again for your help so far.
Paul.

You should be measuring only DC voltage everywhere after that voltage regulator. The only place to measure AC voltage is at the power transformer.

10.7VAC sounds a little low for the voltage at the transformer secondary... that will rectify to only about 15VAC before any filtering, and with 2 volts of losses thru the voltage regulator, that should put your circuit supply voltage at around 13VDC. That's a full two volts under the design center of the circuit. I think it should still work on only 13VDC, though - it wouldn't be optimum, but it should still at least work. So that leaves some other components to take a look at.

With the information you have given, I am still not sure why you are only measuring less than 12 volts...

[newperson]

Hi again,
I have the ADA flanger IC DC volt readings for you to see now.  IC5 looks funny.  As you can see all of them look low.  I am going to order some chips tomorrow.  Do you think IC5 would be a good place to start or is 1/2 of that chip not used and that is why it is all at 0Volts?

IC1:
1-    5
2-    5
3-    2.56
4-    10
5-    6.35
6-    6.82
7-    6.82
8-    5
9-    5
10-  5
11-  0
12-  4.83
13-  5
14-  5


IC2:
1-   3.37
2    3.35
3-   3.25
4-   9.9
5-   4.95
6-   4.95
7-   4.28
8-   5
9-   5
10-  4.83
11-  0
12-   4.95
13-   4.95
14-   4.95

IC3:
1-    7
2     5.3
3-    5.2
4-    0
5-    2.7
6-    2.78
7-    1.6
8-    5
9-    4.8
10-   5
11-   10.1
12-   4.7
13-   4 moving
14-   5

IC4:
1-     9
2-     5
3-     2.8
4-    0
5-    10
6-    5
7-    3.8
8-    5

IC5:
1-    0
2-    0
3-    0
4-    0
5-    0
6-    0
7-    0
8-    10
9-    10
10-    0.1
11-    6.7
12-    7
13-    0.04
14-    0

IC6:
1-    10
2-     0.1
3-    6.7
4-    10
5-    10.1
6-    10.1
7-    0
8-    10
9-    10.1
10-    0
11-    10.1
12-    0
13-    0
14-    0

IC7: voltage reg chip
1-    10.1
2-    0
3-    11.57


IC8:
1-    9.9
2-    10
3-    6.7
4-    0.69
5-    6.7
6-    0
7-    0
8-    7.45
9-    9.5
10-    0
11-    0
12-    10.1
13-    9.6
14-    9.6

Transformer
DC secondary has four pins reading top to bottom from transformer side
1:     4.7
2:     4.45
3:     0
4:     4.5

Transistor:
1:     4.4
2:     4.9 middle pin
3:      4.9

AC Main side
122 VAC


Thank you,
Paul

[moosapotamus]

Sounds like something is wrong with your power supply. I'd get that sorted out first, provide the correct voltage required for the circuit, before doing anything with the rest of the circuit.

~ Charlie

[Paul Marossy]

Sounds like something is wrong with your power supply. I'd get that sorted out first, provide the correct voltage required for the circuit, before doing anything with the rest of the circuit.

~ Charlie

I agree, something is not right with the power supply. You should be getting ~15 VDC on Pin 3 of IC-7. Going back to your original hunch, it sounds like maybe the power transformer got damaged somehow and is not generating enough voltage on the secondary anymore.

[newperson]

Hello again,
Just an update.  I ordered all the chips and a wall wart.  I first tried the one with mainly O voltage but that did not solve the problem.  Then I just stuck all the others in, and sure enough it works.  The DC power still reads low according to the 15v requirements, but all the knobs work.  I am not going to mess with the power supply right now.  What do you think would happen if I put a higher voltage to the unit? 

This is my first time playing with one of these.  It has a long sweep, and manual knob works to mess with the sweep just as you are turning it.  The speed goes to a nice slow speed to a very quick wobble.  And the enhance seems to enhance fine enough.  The odd/even does not seem to be super different.  I can hear a change but nothing night/day.  And the harmonics knob does not seem to be a night/day difference between the settings.

Is there a way to change the limit function?  It seems to only turn on if you are playing or picking at a certain level.  Does one of the trim pots control this?  I don't have a scope so I cannot set any of the trim pots other than by ear.  I cannot tell what a couple of them do.  Can you tell me what all of the trim pots should be effecting?

Thank you,
Paul.

[oldschoolanalog]

Fix the power supply. This unit was designed to work at 15V.
Then see if your problems still exist...

[Paul Marossy]

Hello again,
Just an update.  I ordered all the chips and a wall wart.  I first tried the one with mainly O voltage but that did not solve the problem.  Then I just stuck all the others in, and sure enough it works.  The DC power still reads low according to the 15v requirements, but all the knobs work.  I am not going to mess with the power supply right now.  What do you think would happen if I put a higher voltage to the unit? 

This is my first time playing with one of these.  It has a long sweep, and manual knob works to mess with the sweep just as you are turning it.  The speed goes to a nice slow speed to a very quick wobble.  And the enhance seems to enhance fine enough.  The odd/even does not seem to be super different.  I can hear a change but nothing night/day.  And the harmonics knob does not seem to be a night/day difference between the settings.

Is there a way to change the limit function?  It seems to only turn on if you are playing or picking at a certain level.  Does one of the trim pots control this?  I don't have a scope so I cannot set any of the trim pots other than by ear.  I cannot tell what a couple of them do.  Can you tell me what all of the trim pots should be effecting?

Thank you,
Paul.

It sounds like it could possibly be the FET, but....

Fix the power supply. This unit was designed to work at 15V.
Then see if your problems still exist...

+1. You need to fix the power supply and then see what you have happening.

[Progorava]

Hi

I`have problems with an old A/DA Flanger.

When I got it it was completely silent. The 18v power supply was dead and output jack broken. I fixed those but now the sound is weak and has lot of noise. The bypass works fine. I tested resistors, trimpots and potentiometers with multimeter and those seem to be fine.

Any ideas where to look next? I`m still learning guitar electronics so any help will be much appreciated.

Thanks!

[Progorava]

I replaced Q1 with j201 and I got the sound back. It still had lot of backround noise. It worked for 2 minutes, made suddenly some bad sounds and broke again. So something kills Q1..