PLEASE help me get my heartthrob tremolo working!

[themosscollector]

I finally have some time to try and debug a couple pedels that i tried to build. The other one is a Rebote 2.5 that i started a different thread for. if you can help me out with that, it would be great too. but here goes......

1.What does it do, not do, and sound like? - singnal passes through when the effect is off, no sound when switch is engaged
2.Name of the circuit = Heartthrob Tremolo by MarkM
3.Source of the circuit (URL of schematic or project) = http://freestompboxes.org/viewtopic.php?f=13&t=627&start=0
4.Any modifications to the circuit? no
5.Any parts substitutions?  No
6.Positive ground to negative ground conversion? No

Battery voltage - 9.94
Voltage at the circuit board end of the red battery lead = 9.63

Voltage at the circuit board end of the black battery lead = 0

Q1
C = 0
B = .45
E = .03

Q2
C= 3.67
B= 2.07
E= 1.46

Q3
C = 9.63
B = 1.23
E = .66

Q4
C= reading is jumping around from 1.45 - 1.08 (what does this mean?)
B= 0.66
E= 0

I am totally new to this so any questions you have, please ask.  im still a little confused about understanding the pinouts so if these voltages look mixed up, i may be getting c, b, and e mixed up.

[themosscollector]

i did a little reserch on the transistor pinout and i was getting it switched up. here is how it reads...

Q1
C = 0
B = .45
E = .03

Q2
C= 1.46
B= 2.07
E= 3.67

Q3
C = 0.66
B = 1.23
E = 9.63

Q4
C= 0
B= 0.66
E=  reading is jumping around from 1.45 - 1.08 (what does this mean?)

any thoughts?

[yodude]

Since you just checked the pinouts, might as well check to see if the transistors are oriented correctly in the circuit.

I think you should have a look at your offboard wiring. Make sure your signal is actually getting to the board and from the board to the output. Do you have an audio probe? And make sure all the grounding is taken care of. Don't be afraid to poke stuff with your finger.

[PerroGrande]

I think you've got some E,B,and C confusion going on.  Perhaps only for the readings, but you may have the orientation wrong on the PCB as well.  Here's why...

In the heartthrob, which is basically a modified Schaller tremolo, Q4's EMITTER is grounded, so it should read 0v.  Likewise for Q1.

Similarly, Q3's COLLECTOR is tied to the positive supply, so it should read at or very near your battery voltage.

In this tremolo, Q3 and Q4 form the LFO (Low frequency Oscillator) for the tremolo.  LFO's can oscillate slow enough to be noticeable on a voltmeter.  This is (hopefully) what you're seeing when you have the voltage jumping around. 

So -- for round one of the troubleshooting, you need to absolutely, positively verify the orientation of the transistors and the readings, along with basic off-board wiring "stuff". 

[themosscollector]

you were right. i was getting the pinout diagram confused. they are oriented correctly and read as follows...
Q1
C = 0.03
B = .45
E = 0

Q2
C= 3.67
B= 2.07
E= 1.46

Q3
C = 9.63
B = 1.23
E = 0.66

Q4
C= jumpin around between 1.45 and 1.08
B= 0.66
E= 0

i went over all the offboard wiring and it all looks ok. so whats next?....

[themosscollector]

forgot to mention that when i originaly wired this up, i had the +,- of the battery leads reversed. could we have some fried components here?

[themosscollector]

well i wend over the board for the hundreth time and found a suspect cold solder joint. i took care of that and added an led to the switch....now were cooking. the pedal sounds great. silly question, but the switch doesnt have to have the led in place for the circuit to work right? i was using aaron offboard wiring but originaly just left out the led.

now if i can old get my rebote 2.5 delay to work. here is the thread if your feeling up to it.....
http://www.diystompboxes.com/smfforum/index.php?topic=73083.0

[John Lyons]

The LED does not have anything to do with the circuit working or not.
It's just to let you know that it's engaged or bypassed.

TrEm On!

john