On to my second troubleshooting project of the day....
I populated the Current Lover board and had the smoking R33 issue (apparently due to incorrectly installed ICs) as here: http://www.madbeanpedals.com/forum/index.php?topic=3184.0 (http://www.madbeanpedals.com/forum/index.php?topic=3184.0)
Now when I connect to test rig, I am not getting a signal at all. It seems like I must have a short and I have gone through the board with DMM and power to find it, but have been scratching my head. I was hoping that someone may be able to help point me in the right direction to where the problem may be so I don't start tearing things apart unnecessarily out of frustration and confusion.
Here are got the voltages I measured for the ICs, transistors and the diodes, as well as pictures.
Thanks in advance for the help!
IC1 - JRC4558D
1 - 4.48
2 - 4.48
3 - 4.00
4 - 0
5 - 4.41
6 - 4.46
7 - 4.46
8 - 8.92
IC2 - MN3207
1 - 0
2 - 4.38
3 - 2.66
4 - 7.64
5 - 7.89
6 - 4.44
7 - 3.68 - 4.03
8 - 4.08 - 4.59
IC3 - CD4049UBE
1 - 8.92
2 - 4.45
3 - 4.44
4 - 4.44
5 - 4.45
6 - 4.43
7 - 4.44
8 - 0
9 - 4.44
10 - 4.43
11 - 4.44
12 - 4.43
13 - 0.18
14 - 4.44
15 - 4.44
16 - 0
IC4 - CD4013BE
1 - 4.44
2 - 4.44
3 - 6.6 - 8.6
4 - 0
5 - 4.46
6 - 0
7 - 0
8 - 0
9 - 0
10 - 0
11 - 0
12 - 0
13 - 8.92
14 - 8.92
IC5 - LM 324N
1 - 4.46
2 - 4.46
3 - 4.40
4 - 8.92
5 - 1.08 - 1.93
6 - 1.08 - 1.94
7 - 1.20 - 3.88
8 - 7.54
9 - 4.04 - 4.20
10 - 2.30 - 5.70
11 - 0
12 - 4.04 - 4.20
13 - 4.05 - 4.21
14 - 3.03 - 5.31
IC6 - LM311P
1 - 0
2 - 1.16 - 3.80
3 - 0.90 - 2.25
4 - 0
5 - 8.92
6 - 8.92
7 - 7.20 - 8.54
8 - 8.92
Q1
E: .01
B: 8.92
C: 9.01
Q2
E: 8.95
B: 8.69
C: 8.93
Q3
E: 8.98
B: 8.90
C: 9.00
D4 Anode: 7.9, cathode: 7.65
D5 Anode: 0, Cathode: 7.9
(http://i.imgur.com/Cufrzg5.jpg)
(http://i.imgur.com/dj6ErD2.jpg)
(http://i.imgur.com/58xHIBg.jpg)
Why is the send/return soldered together?
In the instructions, under the "Notes" section, it says: "Two SND/RTN pads are included if you wish to experiment with a through-zero type flanging effect. If you do not wish to use this feature, you will need to jumper the two pads together for correct operation. Is that not correct then??
That is correct.
Q1s Emitter & Q3...
Audio probe might be helpful.
I went through with audio probe and schematic and am stumped as the signal doesn't get too far.
The audio signal works on the schematic from IN1 and does NOT work at the GND connection for R2 (checked continuity between R2 and GND pad was OK). Signal also works from IN1 to R6 and C2 and doesn't travel across the two. Should I swap out those parts next to see if one of them is bad? I have already resoldered those connections.
Of course there's no audio at ground... it's ground! Haha.
Check IC1 Pin 1, IC1 Pin 7, Q3 emitter and Q3 collector.
You get no signal at the end of C6 as it's the inverting input.
Ok, wasn't sure if that were the case with ground... Thanks for the help as I'm definitely learning here-- the other boards I managed to troubleshoot with the test rig/audio probe and follow the schematic were much less complicated...
IC1 pin 1 has signal, no signal on pin 7... No signal at all on Q3... Does this mean the chip may be no good?
Swapped the IC out for another I had in a working circuit with same result... Am I correct that there is limey an issue with R5, R6, or C2?
Could be R5, 6 or C2, could also be R7... the feedback path could affect it depending on what was going on but start there.
Unlikely you have a bad part.
I removed and replaced R5, R6, R7 and C2 but have the same result.... :( What do you suggest I do to check the feedback loop??
You don't need to remove parts, a resistor or cap is very unlikely to be bad.
You had flanging before? Correct?
Honestly, I don't recall if there was any flanging the first 2 times I powered it up because of the issue with smoking R33... I would venture to guess not.
I noticed that I am getting 0v on the side of D5 that goes to GND... Is that correct, or should there be some voltage there?? I resoldered the joint but still get a reading of 0v.
0V on Gnd is what you want :) Ground is ground .
Since the audio probe led me to the R 5-7 / C2 area, I used another wire to jump from R5 to the opposite side of R6 and that seems to give me a signal. Otherwise there is flanging, but the volume of the input is extremely low... does this tell us anything? I verified that the values of R5 and R6 are correct (and had replaced them per the post above)...
R8... have you got a 5.6R resistor there instead of 5k6?
Quote from: Scruffie on November 08, 2014, 01:00:08 PM
R8... have you got a 5.6R resistor there instead of 5k6?
good eyes. its looks like it to me, also.
Oh man... I just found that my stash of supposed 5k6 resistors were mislabeled... Hopefully, this does the trick and saves me from problems on some other builds I have almost completed.
Regardless, thanks for all the help thus far and your patience. Lesson learned.
Looks like I'm going to be headed to Fry's this afternoon.
I'm having issues with my Current Lover build but....I'll still chime in on a couple of things I notice. Is it me or is there jumper missing for your v3207 on the underside of the board?
Also, is the diode on the underside of the board D5? If so, shouldn't it be turned the other way around? Just out of curiosity, why is the diode stuck to the underside of the board like that?
I truly apologize if this just adds to the confusion.
Be careful how many times you solder and desolder those pads......with enough heat they will lift