SOLVED low tide and caesar chorus doesn't modulate

[makisushi]

.

 

[mybud]

Try gently wiggling the socketed transistors to ensure they're making contact all the way. Bear in mind that the biasing can be finicky; IOW, there's a narrow band within which the BBDs function. Finally, if there's bridging required for the ICs, check that this matches the chosen BBDs.

 

[makisushi]

.

 

[mybud]

thank you for the reply! I did try to press all IC, transistor etc but It didn't do much. What I find odd is that I have the similar issue in both pedal.

You're very welcome. From what I can see, it looks pretty tidy and you've double-checked component values already. Try searching the forum for any additional info on these pedals. There may be some troubleshooting ideas right here. I had some issues with the Caesar IIRC. Let me see what I can find.

 

[Robert]

If you hear a chorusing effect when sweeping the knobs on the Caesar the BBDs are working.... The delay is present, it's just not being modulated by the LFO.

The Caesar is directly compatible with V3207D / V3102D, no jumpers/bridges are required on this one.

 

[makisushi]

yes thats exaclty the issue: no lfo, (no pulse on the caesar either). I hear the chorus mostly when I'm moving the lag knob. what would cause a "no lfo" issue on both pedal?

 

[mybud]

I don't know if this'll help but I found some working voltages from a previous Caesar build. The two 'Mine' columns refer.

Yours	Mine
IC1 (TL022)		(TL062 subbed)
Pin 1: 0.65 - 7.86	Varies	0.764 - 5.685
Pin 2: 4.08 - 4.47	4.3	3.99 - 4.12
Pin 3: 1.46 - 6.59	Varies	Varies
Pin 4: 0	0	0
Pin 5: 4.05 - 4.45	4.3	3.96 - 4.17
Pin 6: 4.57	4.3	3.96 - 4.17
Pin 7: 1 - 6	Varies	Varies
Pin 8: 8.52	8.5	8.12
IC2 (RC4558)
Pin 1: 8.73	6	3.88
Pin 2: 8.69	6	3.89
Pin 3: 8.74	6	3.89
Pin 4: 0	0	0
Pin 5: 8.75	6	3.89
Pin 6: 8.74	6	3.89
Pin 7: 8.70	6	3.89
Pin 8: 8.75	8.8	8.23
IC3 (V3207D)
Pin 1: 0	0	0
Pin 2: 3.89	4	3.89
Pin 3: 7.77	5.2	3.12
Pin 4: 7.95	8	7.58
Pin 5: 8.53	8.6	8.15
Pin 6: 3.79	3.9	3.88
Pin 7: 7.90	6.5	3.65
Pin 8: 7.89	6.5	3.65
IC4 (V3102D)
Pin 1: 8.53	8.6	8.15
Pin 2: 3.79	3.9	3.88
Pin 3: 0	0	0
Pin 4: 3.89	4	3.92
Pin 5: 0.80	0.8	0.390
Pin 6: 7.54	7.6	7.59
Pin 7: 2.64	2.9	2.34
Pin 8: 7.95	8	7.57

 

[makisushi]

..

 

[Erik S]

Those Coolaudio are not too good.

I used coolaudio BBDs from Stompbox parts in a Caesar and three low tide builds recently and they all worked fine.

 

[mybud]

Thanx for the IC voltages. I tried changing the opamp on both pedals and still nothing. I ordered some cheap NOS BBD from china. I'll try swapping them before digging any deeper. I once had a defective Maestro chorus pedal with a bad BBD and the sound was pretty much the same as what is happening right now. Those Coolaudio are not too good.

If you recall @Robert’s post above, I don’t think it’s the BBDs (at least in the Caesar build). The problem seems to lie with the oscillator part of the circuit. Maybe see if you are getting any pulses in that part of the circuit before replacing the BBDs.

 

[makisushi]

.

 

[mybud]

When did you buy them? https://www.freestompboxes.org/viewtopic.php?p=302125. This was my exact experience with this (great) pedal. The UC200 from Behringer also have this common issue were they just stop working. Behringer own Coolaudio. Maybe they had a bad batch or something... I could also be wrong, it's just based on my experience with this chip. Glad that some have success with it

I'm not a schematic expert, any specific part to look at on the PCB? It's easier to swap IC and transistor before unsoldering stuff maybe i'm putting all my hope on the BBD for that

I’d start with the pins with varying voltage on IC1, which is the oscillator chip. You do have an 022 there, right? Do you have a multimeter?

 

[mybud]

Ok, hope this clarifies things a bit. You should be getting visual feedback from the LED as far as I can tell. Also, I found a note on the 022 stating that an 062 will also work.

 

[makisushi]

.

 

[mybud]

hey thanx a lot for the visual cues on the schematic. I'll test that later and post the result. It's a good idea to focus on one pedal. I'll test pin 1 on the tl022. Is this the correct pinout? mines are TL022CP


View attachment 93391

Yes, that looks right. Check pins 1 and 7 for good measure.

 

[makisushi]

.

 

[mybud]

I'm not so sure how to measure an IC do i use pin 4 for ground or the boards ground or it doesn't mather since it's the same ground?

TL022:
Pin 1 with 4 i get 8.26V
Pin 1 with ground i get 8.26V
Pin 7 with 4 .718V
Pin 7 ground I get .718V

I think take board ground as your reference and if so, pins 1 and 7 should vary in accordance with the rate pot.

But the vital diagnostic question is whether or not the rate LED is pulsing.

Conversely, if the LED is either off or continuously on, we’ve narrowed the problem down considerably and something is funky with the LFO section. Have you confirmed the LED’s orientation is correct?

 

[makisushi]

all knobs in middle position

tl022:
1 8.27
2 4.25
3 0.315 -- Note: the pulse led light up when grounded with the case
4 0
5 4.24
6 5.55
7 0.71
8 8.97

 

[makisushi]

.

 

[makisushi]

.