Build Your Own Clone Message Board

Sooo...
Ive been troubleshooting this one for a whileput it away for a couple of weeks and now and am at the point where I could use another set of eyes and brains.
after reflowing the board many times, checking the components etc to no avail...

Bypass works.
When pedal engaged(switched on) LED Lights up. signal passes through to output but there is no vibrato. sounds as if there is a very very short delay or almost a light reverb effect when switched on. . Dialing the pots has no effect. ramp on or off has no effect and ramp footswitch has no effect.

Using a signal tester. sound passes through the complete first half of the signal path r1-r24 to output.
if I dial the trim 2 back and forth I get a warble effect when I turn it back and forth fast.

the second half of the signal path r25-r53 has no audio signal passing through.
it does have places where there is an audible pulse that changes tempo when i turn the rate knob.

there is no audio passing through 3207 or 3102 not sure if it is supposed to...

voltages for the ics and transistors
using the pcb map order from the link in the forum for the analog vibrato v2.0
TL072
1 4.7
2 4.7
3 4.7
4 0
5 4.5
6 4.7
7 4~5
8 9.4

4558
1 4.4
2 4.4
3 4.4
4 0
5 4.4
6 4.4
7 4.4
8 9.4

3207
1 0
2 4.1
3 3.8
4 8
5 8.5
6 4.1
7 5.3
8 5.3

3102
1 8.5
2 4.1
3 0
4 4.1
5 0.3
6 8.2
7 3.3
8 7.9

6110
1 4.7
2 4.7
3 0
4 0.2
5 0
6 4.6
7 4.6
8 4.7
9 9.3
E B C
Q1 2.4 2.9 9.3
Q2 3.8 4.4 9.3
Q3 3.3 3.8 9.3
Q4 2.6 3.2 9.3
Q5 4.6 4.6~5 6.5~8
Q6 3.2 3.7 8.4
Q7 0 0.4 7.4
Q8 9.2 8.7 0
Q9 9.1 8.7 0
Q10 0 0.6 8.8
Q11 0 0.6 0.6
Q12 8.3 8.8 9.2
Q13 9.2 8.6 9.2
Qva 8.35 9 9.2

(the transistors are all in correct alignment to the pcb if the numbers are backwards it is because i typed them in in the wrong order)

Any thoughts, ideas, theory is greatly appreciated!
Thank You!

Your IC voltages all compare very closely with my own with the exception of pin 4 of the 6110. I see 1.2V there where you report 0.2. I also see 1.2V on the collector of Q8, which checks out with the schematic, since pin 4 of the 6110 connects directly with the Q8 collector. Not a huge difference, so I'm not sure if it's significant. But it could be.

My other transistor voltages also generally agree well with yours. The one large discrepancy is the collector of Q9, where I see about 9V. Since the base and collector of Q9 are tied together per the schematic, you should see the same voltage on both, but you reported B=8.7V and C=0V. You should recheck this voltage reading. I suspect you just had a bad reading, but that needs to be confirmed.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thank you! I will check this evening and report back! I appreciate it

While you're at it, it would be a good idea to check the voltage again on pin 4 of the 6110 and the Q8 collector. Since they are connected, you should see the same voltage on each.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

FYI, R1 ~ 24 is the audio signal. The rest deals with the low frequency oscillator, ramp, and clock driver. The fact that you can modulate pitch by manually turning the delay time trim pot suggests that the V3207 and V3102 are working fine. You're voltages suggest the LFO is working fine. So you're probably on the right track by looking for the problem in the ramp circuit.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Using a new battery.
6110
1)4.7
2)4.7
3)0
4)0.02
5)0
6)4.6
7)4.6
4.7
9)9.4

I think this is CBE
Q8).02,8.88,9.32
Q9)8.88,8.88,9.34 previous reading error

when listening with an audio probe to the second half of the signal i can change the rate of pulse with the rate pot. is that affecting the LFO or the clock driver?
thank you!

Re: ramp switch...One thing I noticed there is no voltage getting to the switch. As in no matter which side is toggled the switch has 0 volts on all 3 leads. I will check when I get back to see if it is footswitch dependent. As in, If I press the footswitch will that send the signal to the toggle switch. I'll see what I find.

Ok!

So I've narrowed it down to a grounding issue(best guess) in the ramp switching section as you suggested correctly. thank you.

- Coming in to R53 I have 8.35v as well as C24.
- Out of R53 0v
- All 3 lugs of SW2 Ramp On/Off are 0v
- In to R54 0v to +V @8.96
- In to C25 0v to ground 0v
- In to R55 0v out 0v
- SW3 0V to Ground 0V

One anomaly is SW2.
How often are switches DOA?
If I push in or wiggle the toggle I get a rapid flux of voltage but can't get a solid reading or get it to stay...
I have reflowed the switch and all components in this section a couple of times and SW2 again for good measure with no change.
Can I jumper the switch to bypass it? to test if it is bad without taking it out.
Attached is the section of schematic with voltage readings.(sorry for the chicken scratch)

I also do not see any bridges grounding it out. i'll add some pics for more eyes... total overkill on the pics below...

Any ideas?
Thanks

DOA switches are rare but certainly not unheard of--they are, after all, electro-mechanical devices and have significantly more failure mode possibilities than purely electronic components (IC's excepted! ). They can also be damaged internally by excessive heat from soldering during installation, though the overall high quality of your build would seem to make that unlikely.

In any case, it's easy to test the switch without removing it. Use the continuity mode of a multimeter to test for continuity between the middle lug and either of the two outer ones. Since it's an on-on switch, one or the other of the outer lugs (but not both!) should have continuity to the center lug at all times.

Alternatively, you could temporarily jumper the center lug to one of the outer lugs (I would use the inner one, as this is the ramp off position) to force a connection. This could be done by just simultaneously touching both lugs with a conductive object like the blade of a screwdriver.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Thanks,

There is definite continuity between all three lugs of the switch!

This would point to a bad switch?

I'll pop it out and jumper it.
If it works with a jumper it will work with a new switch correct?

Gfr (grand funk)started playing in my head...
I'm getting closer to my hoooommme" haha...

Yes, if the jumpers fix it, then it would be safe to assume that a new switch would do the trick as well.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Yes, that would indicate a faulty switch, but this result is inconsistent with the behavior you've described. On my own AV, I switched the Ramp mode on and then shorted the inner lug to the center lug, which is the ramp off position. The pedal immediately produced vibrato effect. This demonstrates that if there is continuity (i.e. a direct connection) between all three lugs, the pedal should be producing vibrato whichever position that the Ramp switch is in. The no-vibrato problem would occur if there was NO continuity between the center lug and the outer lugs in either switch position.

Could you please describe exactly how you determined that there was continuity between all three lugs of the switch?


I would hold off on this for now, until you've answered my question above.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Nope not the switch. When I pulled it out there is no longer continuity between all 3 lugs.

Haha
Cart before the horse.

I tested continuity by testing the 3 lugs in all combinations. But obviously continuity is outside the switch.

It's still not clear to me exactly how you did the continuity testing. Please explain.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Sorry.
I put my mm onto continuity beep mode.
Then touched the lugs of the switch first middle+left, then middle+right, then left+ right. I received a continuity beep for each of those. Then I switched the switch to the other "on" position and did the same as above and received continuity beeps on each of those.

Then I took the switch out. And tested for continuity as above and showed continuity on middle+left but not middle+right and the opposite when I switched to the other "on" position. And none on the outer lugs.

Then I put the switch back in and repeated with same result as above when switch in circuit.

Would mean that my vibrato should be "always on"...

Correct. Refer to the ramp section of the schematic (below) to see how this works. The Ramp toggle switch provides one of two possible paths to ground. In the "off" position, there is a direct connection to ground through the inner lug of the switch. In the "on" position, the connection goes through the outer lug and a 100 ohm resistor to the Ramp footswitch; depressing that footswitch then completes the connection to ground and "ramps on" the vibrato effect.

BTW, when you have the Ramp toggle switch in the "on" position, have you tested for vibrato by depressing the Ramp footswitch?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

ok i had to take a break.



I was showing grounding on both outer lugs of the switch. and voltage on the inner lug.
this was giving me ground all through the ramp switch. R54,55 and C25.

I took the toggle switch out of the circuit again and disconnected the ramp footswitch.

I remeasured the continuity of the toggle and it is showing continuity between all lugs in both positions. as in beeping no matter what two lugs i touch switch in both positions.

remeasured again: with no jumpers or switch in place
I am getting voltage off of R53 on to the center lug of the switch @ 7.9v.
I am ground on the outer lug closest to the potentiometers.
and now on the outer lug closes to the edge of the board am getting a reading of 8.61(when the toggle switch was in i had 0v on this lug and down through the ramp circuit.)
now i have that 8.61v down into the ramp circuit.

reconnecting the ramp footswitch i am able to toggle off the 8.61v from the lateral lug to ground by pressing the footswitch. footswitch works. (does not engage vibrato but cuts the outer lateral lug from the toggle switch to ground)

Toggle switch removed using jumper: (i have not done this yet wanted to confirm above looks right. i had a discrepancy between my center lug 7.9v and your "Duhvoodooman" center lug of 0v)

my assumptions:
Ramp off would connect inner lug to outer lug closest to potentiometers?
Ramp on would connect inner lug to outer lug closes to edge of pcb?
Grounding out the center lug should activate vibrato? which means if my toggle switch was bad, vibrato should have been always on because the entire switch was grounded... but because I was not getting vibrato by grounding out the center lug that means the issue is not in the ramp circuit? getting ahead of myself...

I appreciate your help. thank you!

Re:audio probe.

Using an audio probe through this circuit is there a place where the vibrato ”shows up"?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok thanks for the reply.

This image was from above. It was my voltage readings before I took out the toggle switch. Readings are per side of each component down the ramp circuit. Showing the whole line was grounding out. I knew it had to be from either switch which is why I disconnected the footswitch too.

Ah, OK, now I see what you were referring to. Yes, makes sense--because of the faulty toggle switch, all those points showing 0V were connected to ground through the left-most switch lug. But as we've said, that only explains why the ramp function wouldn't work, not why there was no vibrato, which should have been on all the time when the pedal was engaged.

You asked about a signal tester (audio probe) before--do you have one of those?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Please check the labeling of ALL six transistors in the ramp section of the circuit, i.e. Q8 to Q13, to be sure that you haven't switched a 3904 and a 3906 in some locations. They should be as follows:

Q8, 9 & 13 = 2N3906
Q10, 11 & 12 = 2N3904

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2