Hello, folks.
So I've built the Small Clone chorus using a kit avaliable here
http://efekty-diy.pl/small%20clone.htmlThe schematic and layout can be downloaded from there upon clicking the British flag. I made no part substitutions.
The problem is that although the signal does go through the unit, there is no modulation whatsoever. I moved the trim pot in both directions, but I've had no luck there. I inspected the board in search of solder bridges, cold joints, shorts and so on, but failed to find anything. I even heated the joints with a soldering iron, just in case, but to no avail. I suppose the problem must be lying elsewhere.
I did do some research on my problem and found some posts on this very forum, but, unfortunately, no one has had the same readings as I have.
I tested the circuit with an audio probe and found that the signal reaches pin 3 of the the MN3007 through the 33k resistor and that's as far as it can get into the modulation circuit. After hours of thinking, reading, testing etc., I finally decided to turn to those smarter and more experienced than me. I am more than certain to get some help here.
The voltage readings are as follows:
Wall wart: 8.96
4558
1. 4.38
2. 4.39
3. 4.28
4. 0
5. 4.34
6. 4. 35
7. 4.32
8. 8.7
MN3007
1. 8.1
2. 0
3. 4.34
4. 0
5. 0
6. 8.1
7. 8.01
8. 8.01
LM358
1. Oscillates from less than 1 V to about 2 V
2. 3.95
3. 3.91
4. 0
5. 0.7-2.9
6. 2.15
7. 0.5-7
8. 8.7
CD4047
1. 0
2. 8.1
3. 0.5-1.6
4. 8.1
5. 8.1
6. 8.1
7. 0
8. 0
9. 0
10. 8.1
11. 0
12. 0
13. 0
14. 8.1
Q1 (2N5087)
C 0
B 3.18
E 3.8
Q2 (2N5088)
C 8.7
B 8.68
E 8.1
Q3 (2N5088)
C 8.7
B 7.4
E 6.9
D1 (1N914)
A 8.12
K 1.25 (at first the voltage goes down to about 0.7 V and then rises to settle at 1.25 V)
D2 (1N914)
A 6.12
K 5.59
Compared to the readings I've seen in other posts the MN3007 and CD4047 voltages are very much off, so I guess they must be the culprits. I did change those chips for new ones, but it didn't help either.
Any help and/or suggestions welcome.
Thanks in advance,
Maciek