Tonepad Small Clone (MN3007) LFO Being Disabled by Depth Switch

[s-roll1989]

I've recently built a Tonepad Small Clone with the stock depth switch instead of the depth pot mod. You can find the schematic here:

http://www.tonepad.com/getFile.asp?id=97

No part substitutions were done except 1N914's in place of the '4148's, and it was built on a Tonepad PCB.

Anyway, the issue I'm having relates to the clock modulation LFO stopping (IC2) when the depth switch is in the open position (i.e. when the switch is not grounding the other side of the 2.7k Ohm resistor Rb). I've checked the integrator output (pin 1 of IC2a) and when the depth switch is closed, I get a triangle wave between 2.25 and 0.62 V. When open, I get a DC signal at 0.62 V, so it looks like the 2.2 uf cap isn't doing its charge/discharge cycle.

From what I've heard on videos of other Small Clones (both EHX and diy) is that both depth switch positions should allow the LFO to operate. So this leads to two questions:

1) Is this normal behavior for this circuit, and I might simply be hearing the videos wrong?
2) Or is there something at fault with my circuit, even though I've checked the connections and pinouts several times?

I've also looked at older topics regarding the small clone and I couldn't find anything on why the LFO would work on only one depth setting.

Anyone's help would be greatly appreciated.

[s-roll1989]

UPDATE:

So I've discovered that the LFO works fine in both depth settings when not connected to the 4047.  I broke the connection between the output of the RC LPF (formed by the 39k resistor and 10uF cap) and the 3 connections to the 4047.  Measuring from the LPF output I got a smoother version of the triangle wave, and the voltage divider formed by Ra and Rb attenuated the wave as I expected. 

Therefore, I am focusing my attention on the 4047 and the weird timing method EHX used with D3 on pin 2.

BTW, I'm using a 4047BE if it matters.

[oskar]

Hello!

1) Is this normal behavior for this circuit...?

Nope!

Have a peek at this guide and provide some voltages:
http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Are the IC's socketed?
If so, also pull out the 4047 and provide voltages with no IC in the socket.

[s-roll1989]

Hi Oskar.  Here are the voltages/waveforms with the 4047 removed:

Vbat = 8.48V

V1 = "sine" with an approx 4 mVp-p amplitude with depth switch open and 3mVp-p closed.  No DC offset.
V2 = 0V (multimeter read 1.6 mV, but it could be noise)
V3 = Sine with depth:
        Open- 2 to 0.75V
        Closed- 0.7 to 0.3V

V4-V6 = 7.68V
V7-V9 = 0V (GND continuity checks out)

V10-V11 = 0V
V12 = 0V
V14 = 7.67V


I also found out I accidentally installed a HCF4047 instead of the CD4047.   
I was looking at the data sheets for both logic families but nothing jumped out at me regarding their affect on this circuit.