Trem Lune Debug Question.

[Evad Nomenclature]

So.

I built a Trem Lune on the Tonepad layout.
I'm getting all the lights and speed stuff working right.  The pedal works in bypass.
I used a Multimeter and did some tests on the IC's and got very close to dead on voltages everywhere.  (battery was a tiny bit lower)
I was confused...
So I ran an audio probe and found that I lost inout once I hit IC#1.  I got signal at pin 1 but it was gone besides that.  At Pin 6 (I should have double checked this, but I'm 95% sure it was pin6.)
I was getting sort of the self oscillation hum, but kind of quiet.

Now, I'm confused since the voltages appear correct, but the audio doesn't make it across... there is no audio anywhere else in the circuit except for some audible tremolo (not on the input signal, but tremolo on whatever noise floor sound there is) later on in the circuit...

I tried swapping out my IC#1 (the 072) with 2 others (to make sure it wasn't fried) as well as put it in backwards from the layout (just to make sure it wasn't weird on there)

no luck.  sooo any ideas?
thanks
dave

[blanik]

a lot of people get the orientation of the LED/LDR wrong on the lune, on the tonepad layout the numbers (VTL5...) go toward the board...

[Evad Nomenclature]

Yep.
I tried flipping it already.
That was actually the first thing i did since I had read some of the other posts saying that a lot of people pop it in backwards.

The thing is, I'm losing audio while *in* the op-amp i believe.  It hit's pin 1 and doesn't go anywhere else... that's the last active spot that I can get audio with the probe, so I'm pretty much sold on the fact that the problem is with that.  I reflowed the solder joints, popped a new op-amp in but still the same thing.  I re-oriented the op amp as well (backward to the  layout instructions)
Is it possible to have a bad socket?  I'm at a loss now.

[MikeH]

Sounds like it's getting lost in the ldr; I'd check component values- it's possible that the ldr is stuck on (or off?) because it's getting too much/not enough voltage.

[Evad Nomenclature]

Hey Mike.

I'll check again later tonight when I get a chance.  I just a few seconds and flip flopped the LDR every which way (just out of sheer guesswork) and the only way that the lights work as well as the speed control (by the light changing speeds) in with the LDR in the original way in which I had it.

It's still weirding me out that I am getting the correct voltages on the first IC, but I'm not getting anything on the audio probe except for pin #1.
It's the last place I have signal in the circuit...

yeah
dave

[Evad Nomenclature]

Ok!

I just saw that I may have misquoted my sources on the voltages.

I am posting them here, just incase the ones I saw listed somewhere else online were incorrect.

My Battery during the MM test is at 8.91 volts, so it's a tiny bit low, but pretty close to fresh
.. here they are.


Trem Lune Debug

Ic#1

Pin #1-   4.37
Pin#2 –  4.35
Pin#3 –  4.13
Pin#4 –  0
Pin #5 – 4.09
Pin # 6- 4.29
Pin #7-  4.29
Pin #8 – 8.53

IC#2

Pin #1- 5.12
Pin #2 –5.09
Pin #3- 5.06
Pin #4 – 0
Pin #5 –4.47
Pin #6 –6.44
Pin #7 – 5.07
Pin #8 – 8.36

LED/LDR – 4.17 on both the pins on the LDR side.
LED 2.50 and 5 volts

Again when testing with an audio probe, the last place I have signal is at pin #1 of the IC#1...
I have reoriented the LED/LDR (even flipped it over... upside down)  the only way I get any of the lights to work is with the current and original orientation, so I believe that it is correct.

any ideas?  I'm dying to get this badboy working...!~

thanks for reading! =P
dave

[Evad Nomenclature]

I'm just bumping this to see if anyone has any ideas since I posted all the values and such.
thanks much   
dave

[GibsonGM]

Sounds like something grounding out with the 1st opamp section, or mistakenly connected to Vref?  Check your pots and their connections, the same thing happened when I made mine ;o)   Could be causing extreme loading downstream from the output of the 1st section...

[Evad Nomenclature]

I got it...
So silly.
It was the LDR.  After all that...

I had tried flipping it back and forth... but apparently *not* upside down (so I couldn't see the text on it)
Mike was right, and i had seen it mentioned like 30 times but hadn't thought of actually turning it *over* duh.
I had been so obsessed with the audio probe... bleh.

Anyway, its done and it sounds totally sick.
Warm sounding trem.. nice.

dave

[MikeH]

...or reverse voltage.

Yeah those LDRs have the one side thats angled-off sort of.  that corresponds to the flat side of the LED in the LDR on the schematic.

[blanik]

I got it...
So silly.
It was the LDR.  After all that...

I had tried flipping it back and forth... but apparently *not* upside down (so I couldn't see the text on it)
Mike was right, and i had seen it mentioned like 30 times but hadn't thought of actually turning it *over* duh.
I had been so obsessed with the audio probe... bleh.

Anyway, its done and it sounds totally sick.
Warm sounding trem.. nice.

dave

i told you so         lol

[Evad Nomenclature]

[/quote]

i told you so         lol
[/quote]

haha sure did... Like my wife tells me though..  I never listen =P
thanks
dave