Chauffeur Overdrive build HELP. (Pictures added)

[marcusbig]

Hi All

I've been working on the Chauffeur Overdrive as my first pedal build.

Chauffeur Overdrive - PedalPCB.com

Compare to Shnobel Tone Daily Driver Overdrive

www.pedalpcb.com

First of all, the inspection of all the parts and the PCB.
Fortunately, I found that one of the PCB patterns is disconnected in the middle of the line between R13 - IC4 6pin (faulty PCB). Anyway, so I patched it up with a wire.

When I turn the pedal off (LED off), I can get sound through the amp (bypass mode).
However, when I turn the pedal ON (LED is ON), I do not get any sound through the amp. Just quiet (no hum) Even if controlled the 4 knobs, nothing changes.

Does anyone have experience with this kind of problem? Or know how to fix it?
Before I give up, I just want to hear someone's technical opinion.

I will be grateful for any help you can provide.
Cheers. Marcus.

 

[music6000]

With Power Unplugged, These matching colours should have Continuity???

 

[marcusbig]

With Power Unplugged, These matching colours should have Continuity???
View attachment 66744

Should have Continuity??? --> YES. Checked with a multimeter.

 

[marcusbig]

Can you remove IC2 & swap with IC1 & see what reading you get in both Positions?

Here are the 'Remove IC2 & swap IC1 or IC3' results of the test.
Please see the picture below.
Thanks.

 

[music6000]

With Power Unplugged, Did you check to see if the matching colours had continuity with non matching colours ie A short!?

Resistor R4-1K seems to be causing an issue & R3 - 22K.
You have the correct voltage on Pins 5 & 6 & they go through those resistors???

 

[marcusbig]

With Power Unplugged, Did you check to see if the matching colours had continuity with non matching colours ie A short!?

Resistor R4-1K seems to be causing an issue & R3 - 22K.
You have the correct voltage on Pins 5 & 6 & they go through those resistors???

YES.
R3 - 22K <------> IC2 pin 5 (GREEN)
R3 - 22K <------> IC2 pin 3 (BLUE)
R4 - 1K <------> IC2 pin 6 (RED)
R4 - 1K <------> IC2 pin 1 &2 (PURPLE)
Note) R3, R4 & R5 resistor values are all correct. (Checked)
Just wondering, do I need to replace any parts?

 

[music6000]

I can only think of changing R3 & R4 as that's where the problem arises!???

 

[marcusbig]

I can only think of changing R3 & R4 as that's where the problem arises!???

Thank you for your advice.
Did you intend to swap R3 and R4 or just replace them with new resistors of the same value?
Do you have any suggestions for circuit checkpoints or parts such as diodes or capacitors?
Thanks.

 

[music6000]

Measure and Replace them with the correct values, it maybe the solder joints!???
Are you using 60/40 Resin core Solder, that's what you should be using!

 

[marcusbig]

Thanks a lot for your advice.

 

[marcusbig]

Found the problem. Awesome tone

[Replaced parts]
1. C4 - Electrolytic capacitor 47uF. (Faulty)
2. Q100, Q101 - 2N4401 NPN TR (Looks OK but just in case)
3. Q102 - 2N4403 PNP TR (Looks OK but just in case)

[Jump Wire]
There is a connection issue between the gain switch and the PCB pattern for C4 due to disconnection.

Special thanks to @music6000 and @comradehoser your guys inspired me.
I appreciate it.

 

[music6000]

Found the problem. Awesome tone

[Replaced parts]
1. C4 - Electrolytic capacitor 47uF. (Faulty)
2. Q100, Q101 - 2N4401 NPN TR (Looks OK but just in case)
3. Q102 - 2N4403 PNP TR (Looks OK but just in case)

[Jump Wire]
There is a connection issue between the gain switch and the PCB pattern for C4 due to disconnection.

Special thanks to @music6000 and @comradehoser your guys inspired me.
I appreciate it.

View attachment 67107 View attachment 67108

Glad that you got it working!
That still doesn't explain why the voltages were amiss from IC2 Pins 1, 2 & 3???

 

[comradehoser]

Well, if marcusbig replaced the transistors, could be that was the issue. Haven't looked at the schematic.

Marcus--in future builds, the next step after visual inspection is always reflow all of your solder joints. You have some sketchy solder points which may have led to poor connections that you could have attributed to faulty components. You want your solder joints to look like shiny little mount fujis. The capacitor looks fine in all of your pics. It is a possibility that it was faulty, but I think the probability is quite low. I also think it is a very low likelihood that the pcb continuity was the issue--however, you could do continuity tests between points on the pcb following the schematic before building anything just so that you rule out PCB issues.

Faulty PCBs and components is usually not the problem in my experience if you've sourced them from reliable vendors/manufacturers; the problem is almost always something I've introduced myself (like putting in wrong ICs). Music6000 helped me out with my sabbra cadabra pedal, for example, by having me jumper a transistor that had a bad connection, but I had broken the trace myself by bending the transistor socket to align it.

 

[Erik S]

the next step after visual inspection is always reflow all of your solder joints.

Do you really reflow every joint every time? I always give mine a careful inspection under magnification and reflow anything that I’m not happy with, but my goal is always to make a nice joint on the first attempt.

 

[jimilee]

Do you really reflow every joint every time? I always give mine a careful inspection under magnification and reflow anything that I’m not happy with, but my goal is always to make a nice joint on the first attempt.

Yessir

 

[Giorfida]

Do you really reflow every joint every time? I always give mine a careful inspection under magnification and reflow anything that I’m not happy with, but my goal is always to make a nice joint on the first attempt.

Considering that I have to set up/tear down my workspace any time I solder (even though for quickies I use my trusty Weller TC iron vs the Hakko station ), the time it takes to reflow them all vs spot checking and reflow is negligible

 

[comradehoser]

Do you really reflow every joint every time? I always give mine a careful inspection under magnification and reflow anything that I’m not happy with, but my goal is always to make a nice joint on the first attempt.

I was talking about the order of operations once your board is not functioning correctly, but actually, I do as a matter of routine inspect and reflow every joint as I solder, especially after I clip the leads--usually I will populate, solder, and clip all of a kind of component at one time--resistors, for example--so there is usually some touch-up needed. I think I have a personal thing with shoddy joints (too bulbous, misshapen, too flat) even if they are functional. I don't like to see that on my boards. And I reflow out of an abundance of caution so I'm fairly sure that the joint is not the issue if issues do arise.

Troubleshooting order when there is trouble for me is:

-inspect cable arrangement and power supply and amp (forget that i've turned down volume/gain or amp gets unplugged)--several times I've plugged outs into ins)
-inspect and manipulate offboard wiring
-jiggle components, especially socketed transistors and ics, as well as 3pdt solder points
-reflow solder
-visual inspection and compare build values directly to build doc
-swap components when possible
-continuity test along schematic
-voltage test
-audio probe along schematic
-post on pedalpcb
-repeat any order of steps above
-be sad and build another pedal

 

[Erik S]

-be sad and build another pedal

 

[Erik S]

@jimilee @Giorfida @comradehoser

I can understand that a standard 100% reflow is cheap insurance, and probably doesn't take that long. I still don't think I'm going to start doing it, but it's cool to see the different ways people go about this stuff.