SOLVED Low tide modulator issues

[ElReverendoRyan]

Hey gang, first time poster here, and first issue I’ve run into like this.

I’m building a low tide, and I’m not getting sound be it bypassed or not. Led lights up just fine. Not yet taken voltages as a prefer to do an audio proble first.

I’m running into trouble at the buffer stage. Didn’t have sk’s so I used j201, but realized I’d soldered too quickly and had the orientation wrong. In a panic took it out but the pads came with. My fault. Anywho.

So now I’m running jumpers from what I understand to be the correct points according to the schematic. If anyone wants to correct me feel free, that’s why I’m here!

G-R5 (have signal here)
S-Positive leg of C19 (no Signal)
D-leg 2 of Q2 (faint distorted signal, that same signal comes out of all 3 legs of Q2)

Any ideas? I probed around for shits and giggles, on the IC I’m getting that crappy signal everywhere all over the board so I definitely think somethings gone wrong with the buffer stage.

As for the bypass, I double checked and everything seems right, but I’ll definitely get around to re-doing the switch connection

 

[Robert]

If you don't have sound in bypass there's an offboard wiring issue of some sort.

Whatever is happening here could be affecting the active operation as well.

 

[ElReverendoRyan]

Alright, had a look over, i had an inverted tip/sleeve thing going on with my output jack, now bypass works fine, when engaged i have a very faint distored signal like what was described. Gate trim works in that it can cut this signal completely. BBD trim seems to have some effect on it too.

I went ahead and took voltage readings on all the chips. The BBD might be iffy, i orded one from Cabintech.

9V is ok at Input

2M358P
1 0
2 2.46
3 2.36
4 0
5 3.32
6 3.32
7 3.33
8 877

V3207d
1 0
2 2.44
3 3..27
4 4.61
5 4.93
6 2.44
7 3.32
8 3.31

LM13700n
1 1.30
2 5.20
3 4.57
4 4.64
5 5.65
6 0
7 5.65
8 4.62
9 4.57
10 572
11 877
12 572
13 4.63
14 4.58
15 5.20
16 1.31

CD4046BE
1 0
2 2.44
3 2.44
4 2.44
5 0
6 0.68
7 0.66
8 0
9 174
10 0.46
11 0.28
12 3.29
13 0
14 4.93
15 003
16 4.93

MCP602
1 1.99 to 2.10 (jumps)
2 1.99 to 2.10 (jumps)
3 0.98 to 1 (jumps)
4 0
5 210
6 210
7 2.30
8 4.93

Randomizer
1 4.31
2 4.93
3 475
4 0
5 214
6 4.93
7 475
8 4.94

Any Ideas? Bueller?

 

[Robert]

Turn Mix all the way down, do you get a clean signal or is it still low/distorted?

If it's still low/distorted you have an issue either in the Input stage (Q1, Q2) or the Output stage (Q4, Q5) and can ignore all of the gate/BBD circuitry for now.

 

[ElReverendoRyan]

Turn Mix all the way down, do you get a clean signal or is it still low/distorted?

If it's still low/distorted you have an issue either in the Input stage (Q1, Q2) or the Output stage (Q4, Q5) and can ignore all of the gate/BBD circuitry for now.

What do you make of my original message? I start getting that distored signal at Q1

 

[Robert]

If that's still the case after correcting the wiring then the problem is in the input stage around Q1.

 

[ElReverendoRyan]

If that's still the case after correcting the wiring then the problem is in the input stage around Q1.

That was it. I tried an 2sk30 instead of the j201 and made sure the pinouts worked against the schematic and it came to life.

Modulation is very subtle, i think i have it biased as good as it will get, and i think that's due to the dodgy bbd. It's socketed so when the real one comes in it'll be an easy swap and i think that issue will go away!

we can call this one, boys! thanks for the quick help!