SOLVED Nobelium build - troubleshooting power issues

[ehguitarguy92]

Hi there! thanks in advance for your help. New-ish user to building and troubleshooting PCB pedals specifically, but experienced with soldering and circuits/components in general.

Recently built a Nobelium circuit, but am trying to troubleshoot why it is not working. I reflowed solder on all joints, tested continuity at a bunch of points, and verified direction of polarized components, etc.

When I plug in power, LED's/tubes do not light up. Measuring ~125V instead of 250V at C1, as well as R10/R11. Voltage at those points fluctuates slightly...and the voltage at the input power jack is also fluctuating up/down regularly.
Powering with a 9v 1Spot wall wart that is working on other pedals - will try to grab another supply to test as well.

Do you think there is a short somewhere in the circuit? (I do not see any solder or component leads touching) Or are there specific places I can test voltage to isolate what the problem may be?
I do have a few more PCB's I have that I was going to build for local friends, so I can always build another to see if that one works, then test back and forth...but if you have any specific testing or troubleshooting advice...would be greatly appreciated.

Thanks!

 

[PunchySunshine]

Hi there! thanks in advance for your help. New-ish user to building and troubleshooting PCB pedals specifically, but experienced with soldering and circuits/components in general.

Recently built a Nobelium circuit, but am trying to troubleshoot why it is not working. I reflowed solder on all joints, tested continuity at a bunch of points, and verified direction of polarized components, etc.

When I plug in power, LED's/tubes do not light up. Measuring ~125V instead of 250V at C1, as well as R10/R11. Voltage at those points fluctuates slightly...and the voltage at the input power jack is also fluctuating up/down regularly.
Powering with a 9v 1Spot wall wart that is working on other pedals - will try to grab another supply to test as well.

Do you think there is a short somewhere in the circuit? (I do not see any solder or component leads touching) Or are there specific places I can test voltage to isolate what the problem may be?
I do have a few more PCB's I have that I was going to build for local friends, so I can always build another to see if that one works, then test back and forth...but if you have any specific testing or troubleshooting advice...would be greatly appreciated.

Thanks!

Is your 1Spot power supply capable of 550mA @ 9v? Also....pictures please.

 

[vigilante398]

I will second the request for pictures and for details about the power supply. A supply working with other pedals doesn't mean much unless the other pedals are also tube pedals.

95% of the "nonworking" pedal complaints I get are from someone trying to use a Boss 150mA supply or Donner 250mA supply. Nobelium will need a lot more than that.

 

[ehguitarguy92]

Pictures attached. Power supply is a 9v 1700mA Max, and I also tried a 10v 850mA supply. Voltage at C1 was ~135v with the 10v supply.
Both power adapters seem to be working ok, and I have a 12v one I could try as well, but would need to flip the polarity of the jack. With the increase of the power at C1 with the 10v supply, wondering if it is a different issue than just the power supply.
Thanks!

 

[vigilante398]

If your LEDs are not lighting up (assuming they're not backwards), there's most likely an issue with the connection between the tube daughter PCB and the main PCB, so that would be the first place to check. Go over the soldering on both boards and check for cold joints or anything that looks suspect. I'm not seeing anything jumping out at me in the pictures, but that's going to be the first place I would recommend checking out.

Just for fun, you may also try checking the voltages with the tubes removed and see if that makes a difference.

 

[ehguitarguy92]

LED's WERE reversed, thanks now they are working.
Reflowed all the daughter board solder points (and most of others for good measure).

My 9V Onespot pedal power (1700ma) was still cycling, will have to try a different one.
WORKS (Partially) using an alternate power supply (9V 1A) that is center positive - I flipped the wiring of the power jack for now to test it with this one. Also works the same way (see below) with the 10v one I have.

Newest issues - with tubes removed or in place, the voltage is still around 125V at C1. I put tubes back in and buttoned up the enclosure to test audio. Signal is passing, but there is a fairly potent 120Hz hum that fluctuates with the bass/treble knobs as well as the high pass, and also passes (60Hz) when volume knob is off. Also, a massive 60Hz hum if the input cable is unplugged. I can send audio samples if helpful - I do not have an oscilloscope handy. Any thoughts on where that could be coming from? Issues with grounding points in the circuit? Or is this related or parallel to the circuit only getting 125V at those spots?

Passes audio though getting closer.

Thanks for all your help guys!

 

[ehguitarguy92]

LED's WERE reversed, thanks now they are working.
Reflowed all the daughter board solder points (and most of others for good measure).

My 9V Onespot pedal power (1700ma) was still cycling, will have to try a different one.
WORKS (Partially) using an alternate power supply (9V 1A) that is center positive - I flipped the wiring of the power jack for now to test it with this one. Also works the same way (see below) with the 10v one I have.

Newest issues - with tubes removed or in place, the voltage is still around 125V at C1. I put tubes back in and buttoned up the enclosure to test audio. Signal is passing, but there is a fairly potent 120Hz hum that fluctuates with the bass/treble knobs as well as the high pass, and also passes (60Hz) when volume knob is off. Also, a massive 60Hz hum if the input cable is unplugged. I can send audio samples if helpful - I do not have an oscilloscope handy. Any thoughts on where that could be coming from? Issues with grounding points in the circuit? Or is this related or parallel to the circuit only getting 125V at those spots?

Passes audio though getting closer.

Thanks for all your help guys!

I should caveat...my house has some power/noise issues from a local transformer in the power grid...so this could very well be directly related to that; I always have major problems with similar types of noise when recording at my house. I will take the pedal to my office tomorrow and test it there to verify. But if you have any thoughts related to the 125V note above, feel free to weigh in if you think that is related in some way.

Thanks again!

 

[drew.spriggs]

Pull R9/10/11.

If you don't have ~250v on the positive of C1 you have a power supply problem

 

[ehguitarguy92]

Pull R9/10/11.

If you don't have ~250v on the positive of C1 you have a power supply problem

Thank you!
I built a second one to test for reference, and followed your suggestion of looking at those points^
I touched up solder points on all of these and power supply points (as well as two on the NE555 socket that tasted different on the first vs second one I built), and now we are off to the races with not one but two working pedals.

Thanks all for your assistance and kind help in troubleshooting! Excited to try them out.

 

[PunchySunshine]

as well as two on the NE555 socket that tasted different

That's commitment! One should always taste their sockets!