General Guitar Gadgets Phase 45 Help

Started by DarrenCotta, December 05, 2011, 02:55:26 AM

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DarrenCotta

Going by the debugging info list...

1.LED works, hum with no guitar signal able to come through
2.General Guitar Gadgets Phase 45
3.http://www.generalguitargadgets.com/pdf/ggg_p45_lo.pdf
4.Didn't connect battery clip. My friend said he'd just use the DC jack.
5.All parts used came with the kit.
6.No ground conversion.
7.Didn't wire battery connector but voltage shows on (analog meter) 8.5 from ground to positive on DC jack.
With the negative lead on signal ground, measure the following:

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1 - (2N5952) - No readings from either Transistor.
D =
S =
G =

Q2 - (2N5952)
D =
S =
G =

IC1 - (TL072)
P1 = 2
P2 = 1
P3 = 1
P4 = 0
P5 = 0
P6 = 5
P7 = 9
P8 = 9.75

IC2 - (TL072)
P1 = 9
P2 = 9.5
P3 = 0
P4 = 0
P5 = 2.5-3.5 (depending on how speed pot is adjusted. At fastest rate, stays a solid 3)
P6 = 2.5
P7 = 9.5
P8 = 9.75

D1 - (1N5230) Not able to get a reading on either end.
A (anode, the non-band end) =
K (cathode, the banded end) =

Based on the results of this, in which I wish they were more accurate with a digital, but if this proves to be obsolete, by all means I will get a hold of a digital meter.
I'm using the ground off of the input jack to test each lead, not sure why I'm not receiving any readings on the diode or transistors. Did I fry something?!
Looking forward to hearing what advice is given. New to the whole pedal building thing. Hope I didn't screw up too badly! Thanks in advance!



DarrenCotta

Also, I should mention some of the results I've gotten from google, mentions the positions of the transistors being turned around.


Govmnt_Lacky

Big time problems:

1) You mention that you are reading 8.5V on the DC jack (power input to citcuit) BUT.... you list a voltage measurement on IC1 Pin 8 of 9.75! Pin 8 on BOTH ICs should be the same as your input voltage.
2) Most of your IC voltages are out to lunch! You should be getting V+ (8.5V) at Pin 8 of both ICs. You should have 0V (GND) on Pin 4 of both ICs. Finally, you should have "around" 1/2 of your input voltage on the rest of the pins (~4.3V)
3) You list no voltages for any transistors or the diode however, there SHOULD BE voltage there. You need to list them.

It looks like you might have some major solder run issues on multiple areas of the board.

BE SURE TO FOLLOW THE DEBUG THREAD CAREFULLY! Check for solder bridges.... correct... then repost voltages if you still have problems

Good Luck  ;D
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

DarrenCotta

Ok, I'm trying to clean the board up, probably ran the soldering gun too hot. Residue left on the board, any chemical solvent to clean that up without ruining the solder on board already?

DarrenCotta

Ok this time around I'm going to include a picture of my solder job. Not sure if you'll be able to see anything, but I figured it's worth a shot.

Rechecked solder points and lightly cleaned the board with alcohol as well. Really irritating  :icon_sad:

ICs are as follows:

IC1:
1- 1.5
2- 1
3-1
4-0
5-0
6-5
7-9
8-9

IC2:
1-9
2-9
3-0
4-0
5-2-4
6-3
7-9
8-9

Diode shows no readings along with both transistors.
Not sure what's going on but here's a shot of the bottom of the PCB.


Govmnt_Lacky

Your voltages at the ICs still look totally wrong. You should ONLY have 9V at Pin 8 on each of the ICs. You are showing that on multiple pins. Problem #1

You are saying that you show no voltages on any of the transistors and the diode (you DID use a zener right?) The banded side of the zener SHOULD show your bias voltage for the transistors (around 3-4V adjustable by the trim pot) the non-banded side of the zener should be ground. Problem #2

You may want to add another pic of the component side of your build. Fresh eyes can catch a lot of missed items for frustrated builders.

My recommendation: Post the new pics. Take some time off. Revisit and verify ALL component values, placement, and orientations (FETs??), then break out the multimeter and verify EVERY trace and make sure there are NO hidden breaks. Also make sure there are no suspect solder bridges. METER OUT EVERY TRACE. Should not take too terribly long but is worth the sanity check.

Good Luck  ;D
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of 'up to and including my life.'

jdub

Have you also verified correct orientation of the opamps?
A boy has never wept nor dashed a thousand kim

p_wats

I definitely had to reverse my transistors when I built this a while back. Give it a shot.

PRR

> Diode shows no readings along with both transistors.

NO reading means the meter is off.

What exactly does it say? 0.00? Overload? ERR? ---? 
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DarrenCotta

Took the day off of messing with it.
Definitely have read about people reversing the polarity of the op amps. Just wasnt sure. Read it worked, read it didn't.  So I'll have to give that a try.
When I was trying to remove the op amps, one of the legs broke on me, so I headed to Radio Shack and got MPF102, which I read was an alternative. Soldered sockets in and replaced both of them with the MPF102s.
I have used the zener diode that came with the kit.

Here's a picture, component side up.




DavenPaget

Try flipping round the MPF102's .
The original 2N5952's were DSG , the MPF102's are GSD .

Hiatus

DarrenCotta

Ok! What then about the diode? I couldn't get a reading on it for the life of me. Just in case I fried that, I bought a 1N4733A, which is a 5.1V Zener.
Would that work? Because the original diode was a 4.7V.

DavenPaget

Quote from: DarrenCotta on December 06, 2011, 10:47:41 PM
Ok! What then about the diode? I couldn't get a reading on it for the life of me. Just in case I fried that, I bought a 1N4733A, which is a 5.1V Zener.
Would that work? Because the original diode was a 4.7V.
5.1V Will be fine , no reading ? It shouldn't give any reading in diode mode , most multimeters do 2.5Vdc for diodes only .
Anyways , it should give a reading when you put your gnd probe to gnd and your + probe to either banded side or non-banded side .
Hiatus