DIYstompboxes.com

Hello, please bear with me because I really don't understand electronics very well. I've built two pedals kits, a spring reverb kit from BYOC and a Helios distortion pedal from Aion Electronics. Both woked perfectly when I buttoned them up and plugged them in. I am pretty good at following directions, going slow, being methodical. I can do kits with good directions.

So I wanted to see if I could start with just a board and build a pedal. So far it seems I can't.

I bought the Nimbus overdrive board from Aion and sourced everything else. Making this one of the most expensive pedals ever. I have it plugged into a Voodoo Labs power source. With the guitar plugged in, pedal on, I get guitar sound as if plugged straight into the amp. No change in tone or sound. Turning the volume, drive or tone knobs does nothing. If I switch the power off, it's as if I unplugged the guitar. No sound to the amp. So I guess it's not passing through.

I've read the trouble shooting sticky and I need to start even more basic than that I guess. I bought a 9v battery jack that I can plug into the pedal for power. With my DMM I confirmed the plug is negative power by putting the negative lead into the plug and touching the positive lead to the outside of the barrel. That reads about 9V, 8.5 I think, new battery. I then plugged the battery into the pedal. I put the negative lead of the DMM on the pedal box and then touched the positive lead to the center of the jack output or where the wire connects the jack to the PCB board and I get -14.9 mV. So it seems I'm doing something wrong from the very beginning.

Hopefully someone would be willing to hold my hand here, walk me through this and teach me a little.

This is the DC power jack I bought off of eBay. Did I buy the wrong thingm

(https://i.postimg.cc/7JMx2fs9/Screenshot-2020-06-19-16-23-08-232-com-ebay-mobile.jpg) (https://postimg.cc/7JMx2fs9)





(https://i.postimg.cc/5XkfLc3h/Screenshot-2020-06-19-16-23-34-982-com-ebay-mobile.jpg) (https://postimg.cc/5XkfLc3h)

(https://i.postimg.cc/WDBjYMxS/Screenshot-2020-06-19-16-23-51-861-com-ebay-mobile.jpg) (https://postimg.cc/WDBjYMxS)

Here's the reading I get

(https://i.postimg.cc/47RyHk4J/IMG-20200619-161431-1.jpg) (https://postimg.cc/47RyHk4J)

(https://i.postimg.cc/Hc0xQZjb/IMG-20200619-161424.jpg) (https://postimg.cc/Hc0xQZjb)

First of all, welcome!

If I got it right, your power supply is negative center. But you're using a metallic power jack.

The metallic jack is touching the outside lug of your dc plug, which is positive. But it's also touching the enclosure, that is wired to ground, that is wired to negative of the dc jack. So it is as if you're shorting the positive and negative pins of your power supply. This is indicated by your measurements, you get 9V before connecting the dc brick to the pedal but get almost zero after connecting it to the pedal. A dc brick will just disarm, while a battery will discharge quickly and get pretty hot.

To be sure, just do this: remove the dc jack from the box. You may have to desolder the wires. If yes, then resolder the wires again and make sure the dc jack isn't touching the enclosure. Connect the power plug again. Test the pedal again.

If it's working, then the problem is the metallic jack. Just get a plastic one. If the problem isn't solved, let us know to tell you the next steps.

The battery does get hot!!!

Sounds like I need to replace it with a plastic one regardless..I picked it just because it looked cool. I never knew there were reasons not too. Thanks! I will order a plastic one and post results after I get it. Probably next week.

-AJ

PS Thanks for the over simplifying your explanation. I actually understood you.

So your battery is probably dead. Rip.

You can use the metallic one if you use a positive center power supply. But the standard power supplies for guitar effects are negative center, you you'll have to use a power supply that'll work for your pedalboard but nobody else.

Before ordering the plastic dc jack, do the test I told you to do, with the dc jack removed from the enclosure. So we'll know if that is the only problem, and hopefully it is.

I cut the wires and reattached outside the box with the jack just hanging in space and not touching anything. When I plug the battery in I get the same readings as before and the battery gets hot. I checked and it's an 8V battery now. So I will just wait until I get a plastic jack and eliminate this as a source of error. And before I screw something up.

Thanks!

-AJ

If the power jack was not touching the case and the battery still gets hot then you have a short on the power supply somewhere on the board.  Take your multimeter with no power connected to the board, and measure the resistance between the +ve and ground.

OK, so if I put one test lead at point A and the other test lead at point B, I think that's what you mean, my meter reads 6.7 when the dial is set at 20K Ohms.
(https://i.postimg.cc/0K8hZJTH/nimbus.jpg) (https://postimg.cc/0K8hZJTH)

OK, R20 and R21 join together.  Measure from that join to both of the pads you have already used (A and B (Gnd and 9V) from above).

Good morning. I might not understand what you mean. I got 6.6 for each.

I measured with one test lead on the +9V (I labeled A above) to the right leg of the R20 resistor and got 6.6 with the dial set at 20K ohms.

I measured with one test lead on the +9V (I labeled A above) to the left leg of the R21 resistor and got 6.6 with the dial set at 20K ohms.

I measured with one test lead on the  GND (I labeled B above) to the right leg of the R20 resistor and got 6.6 with the dial set at 20K ohms.

I measured with one test lead on the  GND (I labeled B above) to the left leg of the R21 resistor and got 6.6 with the dial set at 20K ohms.

It was pretty consistent. The second decimal would be different but it was 6.6 something for all of them.

-AJ

please assist us to assist you - post photos of your built board, both sides, and shots of your offboard wirings, please. it is also polite to at the very least provide a link to a circuit diagram or build docs of the version you've built.

thank you.

Sure.


(https://i.postimg.cc/dL7h1D1G/IMG-20200619-155157.jpg) (https://postimg.cc/dL7h1D1G)


(https://i.postimg.cc/BjHtTy26/IMG-20200619-155258.jpg) (https://postimg.cc/BjHtTy26)

I'm not sure how to post the wiring diagram since it's a PDF but here is the link to the board.
https://aionelectronics.com/project/nimbus-maxon-od-820-overdrive-pro-pcb/ (https://aionelectronics.com/project/nimbus-maxon-od-820-overdrive-pro-pcb/)

assuming this is your version .....
https://www.dropbox.com/s/3mayaqit8atqnju/aion-nimbus-od820-documentation.pdf?dl=1

I can't see much from your far away pics [we like to be close enough to read the resistor colour bands], but two things: are all you tantalum capacitors the right way around? they are marked with a (+) leg as opposed to normal electros, marked for the (-) leg.

and - I couldn't see it mentioned in the docs I linked, but I think your diodes D1 and D2 should solder to the first and fourth pads when only fitting singles; you have soldered to second and third, which from what I see on yer blank pcb, are shorted pads.

OK thanks. That's the one.

Yes, I didn't understand where the diodes went so I put them in the two middle holes. So they should be in the outer holes. I will fix that. Thanks!

I feel good the capacitors are correct because I paid close attention. Is there a way to double check? Unless you're saying I used the wrong kind to start with?

I'm not sure how to get a better picture with my phone but I'll see what I can do.

-AJ

I played around with the manual settings on my camera phone, I've never been in there before. Maybe these are a little better.


(https://i.postimg.cc/0K64NTJ9/IMG-20200620-165724.jpg) (https://postimg.cc/0K64NTJ9)


(https://i.postimg.cc/py77SLgr/IMG-20200620-165828-1.jpg) (https://postimg.cc/py77SLgr)

Just to be sure, what's the resistence between +9V and gnd pads? The ones you labelled A and B. Measure with the probes directly on them, with no power.

Also, can you remove some parts from the board to do some testings? I mean, do you have the tools/skill to remove a part without damaging the board from overheating if asked?

Hi. Yes, that 6.7 number I measured was with no power on. I don't know what that means.

Yes, I can desolder. Back in college I worked at a plant making High I drives and power supplies. I had no idea what I was doing or even what a high I drive was, but like I said I was really good at following directions.

So I may not understand what I'm doing, but will follow whatever directions you give me. :)

Thanks!

-AJ

I had to source everything from scratch. The resistors were easy. But I did struggle on buying the capacitors. Perhaps I bought or used the wrong thing. So I put together a list of what the instructions called for and what I bought.

Build List      What I purchased

C1 100n      Wima 0.1µF 5% 63V
C2 1uF film   Wima MKS2-1.0/63/10 1uF 63VDC 10% Polyester (PET) Film Capacitor Radial
C3 100pF 1   100pF, 50V, radial leaded multilayer ceramic capacitor, coating by epoxy resin.
C4 100n      Same as C1
C5 220n      Wima 0.22µF 5% 63V
C6 10n      Wima 0.01µF 5% 63V
C7 220n      Same as C5
C8 10pF 1      10pF, 50V, radial leaded multilayer ceramic capacitor, coating by epoxy resin.
C9 220n      Same as C5
C10 10uF 2   16V 10uF tantalum
C11 20pF 1   20pF, 50V, radial leaded multilayer ceramic capacitor, coating by epoxy resin.
C12 1uF film   Same as C2
C13 100uF 25v   Panasonic FM 100uF 25V Low-ESR 105C USA SELLER
C14 10uF      Same as C10
C15 100uF 25v   Same as C13
C16 10uF      Same as C10
C17 10uF      Same as C10
C18 220uF 16v   Panasonic Radial Capacitor 220uF 16v EEU-FC1C221 105'C Low Impedance
C19 220uF 16v   Same as C19

Semiconductors
Q1 2SK246         2SK246-Y Original New Toshiba TO-92 MOSFET K246
IC1 - IC2 JRC4558D      JRC4558D OpAmp
IC3 TC1044S         TC1044SCPA
D1 - D2 1N914 3      NTE Electronics 1N914 Silicon Ultra Fast Switch Rectifier Small Zener Diode, Single Configuration, 200 mA Forward Current,                                                     10mA Test Conditions, 100V
D3 - D5 1N4001      uxcell a11092900ux0407 25 x 1N4001 Molded Plastic Case Rectifier Diodes, 1A, 50V

1 Can be ceramic or film. I prefer to use multilayer ceramic capacitors (MLCC) for these small values.
2 Can be electrolytic or tantalum. C10 is in the signal path.

Thank everyone for your patience with me.

-AJ

So, a brief explanation is that the point where R20 and R21 join is "half way" between the 9v and Gnd rails.  On the photo of your board above, that would be the right side of R20 or the left side of R21.  In fact, if you measure the resistance from the right side of R20 and the left side of R21 you should get 0 - indicating that they are joined together.  As R20 and R21 are each 10k resistors, you should be measuring approximately 20k between 9V and Gnd (The 2 resistances add up).  A bit lower is to be expected because of the rest of the circuit interfering a bit.  That "half way" point should give 2 readings - one to Gnd and one to 9V.  Those 2 readings should add up to the reading that you get from 9V to GND because of the way that resistances add up.  Getting about 6.6k between the half way point and GND is about right.  Getting 6.6k between the half way point and 9V is also about right.  If both those are 6.6k though, you should be measuring 13.2k between 9V and gnd, but you are measuring 6.7k, which doesn't really make sense.  If 6.7k between 9V and gnd is correct, then that would indicate that one of the measurement to the half way point should be 0 - which would show a lot about where to start looking for your problem.  Can you please take those measurements again.

OK I got a helper it help me document.

So here is +9V to GND

(https://i.postimg.cc/YvrksDmb/IMG-20200621-133955.jpg) (https://postimg.cc/YvrksDmb)

Here is +9V to right leg of R20

(https://i.postimg.cc/fVLpdGdn/IMG-20200621-135008.jpg) (https://postimg.cc/fVLpdGdn)

Here is +9V to left leg of R21

(https://i.postimg.cc/kB19LFFC/IMG-20200621-135033.jpg) (https://postimg.cc/kB19LFFC)

Here is right leg of R20 to GND

(https://i.postimg.cc/HJ5gcGGW/IMG-20200621-135046.jpg) (https://postimg.cc/HJ5gcGGW)

Here is left leg of R21 to GND

(https://i.postimg.cc/rRyXPKDz/IMG-20200621-135058.jpg) (https://postimg.cc/rRyXPKDz)

Quote from: ajhuff on June 20, 2020, 10:25:29 PM
IC1 - IC2 JRC4558D      JRC4558D OpAmp

Well there aren't any actual JRC4558Ds in your pictures, so those are fakes.  Some people get working fakes, so that may not be related to your problem, but do buy from reputable vendors like Mouser, Small Bear, DigiKey, or Tayda.  I would avoid Alibaba, AliExpress, or anything on Ebay from China.

OK thanks. I did buy them off eBay but not from China. They were labeled as JRC4558D  OpAmp TUBE SCREAMER ,PEAVEY ,Orange replaces LM4558, RC4558. But I didn't know what I was doing.

I will check Mouser.

-AJ

It indeed could be a bad ic that are shorting the power supply. Try to do this test:
- remove all the ics. Easy to do, since they're all on sockets.
- power the pedal. I don't know if you used a stereo jack to switch power on, if yes then plug in a cable. Use the dc brick with the metallic jack not touching the enclosure or use a fresh battery, the one that got hot is probably dead.
- measure the voltage between gnd and +9V.

If you get a measurement that's close to 9V, then put IC3 on the socket, put the black probe on gnd and with the red probe measure the voltages on pins 4 and 8 of the sockets of IC1 and IC2.

Your pictures show that your multimeter is in resistance test mode (Ohms ). To measure voltages turn the meter selector switch to position 20 V DC and redo the R20, R21 voltage measurements (power must be supplied to the effect ).
If you are uncertain that you have the correct voltage range selected on your multimeter then just measure your 9V battery. The meter should display a reading somewhere near 9.00V

Edit: I forgot to ask; You have used some tantalum capacitors in this build. Tantalum capacitors can be difficult to install  with the correct polarity (usually not marked clearly ). Are you certain that they are all installed correctly?

Yet another edit: Now that I have actually managed to read the entire thread  :icon_rolleyes: ....Please ignore this post. Sorry everyone  :icon_redface:.

OK, I took the three IC chips out.
This is what they look like BTW, if I bought the wrong thing.

(https://i.postimg.cc/0KxcvyJS/IMG-20200621-180801.jpg) (https://postimg.cc/0KxcvyJS)

(https://i.postimg.cc/BPgNnfxV/IMG-20200621-181120.jpg) (https://postimg.cc/BPgNnfxV)

So, hooked battery up to metal jack hanging freely, not touching the case. Battery read 8.75V. Plugged a guitar cable in. With the red test lead on the +9V and black test lead on GND it read -1.5V. I pressed and depressed the foot switch but that number didn't change. I didn't check the voltage at the socket pins since I didnt  get 8.75V between +9V and GND.

-AJ

That test confirms there's indeed a short somewhere on your board. Measure the resistence between +9V and gnd pads, just to be sure. Don't need to power the circuit for this test, as long as the metal jack is not touching the enclosure.

OK. Hopefully that's progress. Thanks again for the small steps.
The resistance from +9V to GND is 6.7 on the 20K ohm setting.

-AJ

If by 6.7 that means 6.7r, there's indeed a short. To be really sure, put the multimeter on the smaller scale and measure it again. If it's still around 6.7 (or any small value), there's a short between gnd and +9V pads. Or just put the multimeter on continuity mode and check if there's continuity between those pads.

If there's continuity/low resistance, post a few more photos of the solder side of the board. The parts' side seems to be good, maybe there's a very small solder bridge between some pads that isn't supposed to be there.

Quote from: ajhuff on June 21, 2020, 07:32:01 PM
OK, I took the three IC chips out.
This is what they look like BTW, if I bought the wrong thing.

(https://i.postimg.cc/0KxcvyJS/IMG-20200621-180801.jpg) (https://postimg.cc/0KxcvyJS)

There seem to be about a bazillion of those fakes with the 0058T code on them.  Again, some people have pedals that work fine with them, meaning they are actual working dual opamps of some kind, in some cases.

The real JRCs look like this, with the circle indentation at pin 1, "JRC" in bolder font, right-justified:
(https://images.reverb.com/image/upload/s--YgDKAZWO--/t_thumb/v1566577604/pljbqwnprj5kqywp6otp.jpg)
The earlier (1980s) ones had a 4-digit code on the bottom, later ones have a 5-character alphanumeric code.

Doing a google image search for "jrc 4558" brings back more fakes than real ones, that's how bad it's getting.

Quote from: Marcos - Munky on June 21, 2020, 10:13:44 PM
If by 6.7 that means 6.7r, there's indeed a short.

I would assume it's 6.7k, since he's on the 20k range.

Quote from: willienillie on June 22, 2020, 12:52:22 AM
There seem to be about a bazillion of those fakes with the 0058T code on them.  Again, some people have pedals that work fine with them, meaning they are actual working dual opamps of some kind, in some cases.

I got 50 of those ones from aliexpress, for a very cheap price. Used about 10 of them, all worked. I don't know what exactly they are, since I can't think on a cheaper opamp than a 4558 to be remarked and sold as a 4558. I can't even think on how profitable is to sell fake 4558s. I mean, for a rare IC, like a bbd or something like that, they can get a IC that costs a few cents and remark it as one that can be sold for a dollar or more. But for faking a 4558 they just get a IC that costs a few cents and remark it as one that costs... a few cents! Probably the cost for remarking the IC is bigger than the profile for selling a fake 4558.

I do believe mine are fakes. The same goes for a bag of jfets I got from aliexpress (which I also used a few and they work but I had to use a totally different value for the bias resistor). Just saying I can't really understand why to counterfeit a so cheap part, it makes no sense.

Back to TC's circuit, so far we can't say those 4558s work or not, but there's indeed a short somewhere, because of the voltage measurement even without all ICs.

I am a bit suspicious of C14.  You could remove it and see what happens to those voltages.  It acts as a filter on the power supply, so without it the circuit would still work perfectly well. 

Quote from: Marcos - Munky on June 22, 2020, 01:29:40 AM
Just saying I can't really understand why to counterfeit a so cheap part, it makes no sense.

I agree.  Maybe they're not remarking chips, but manufacturing them as fakes from the get-go, figuring they can get 2 cents more each with the brand recognition.  2 cents x a bazillion = real money.

(https://i.postimg.cc/NF2V1ysd/IMG-20200621-180801.jpg)

like that guy ^ sez. squint at this pic, it could be made a poster of what to look for. note well the difference in shape and method of the pin 1 divots, and the one chip has chamfered all round body, the other doesn't. yet both show the same date code, both show the exact same size shape spacing weight and content of the print printed.

also - never buy before checking the datasheet. if the datasheet sez :

QuoteTOSHIBA Field Effect Transistor Silicon N Channel Junction Type 2SK246

and the advert you are looking sez  :

Quote2SK246-Y Original New Toshiba TO-92 MOSFET K246

..... close the page, look elsewhere. it ain't worth the hassle.

Quote from: willienillie on June 22, 2020, 12:53:42 AM

Quote from: Marcos - Munky on June 21, 2020, 10:13:44 PM
If by 6.7 that means 6.7r, there's indeed a short.

I would assume it's 6.7k, since he's on the 20k range.

Sorry, I didn't know if you were supposed to halve the number or double it since the  dial setting says 20K so I just reported 6.7 of the 20K setting. I'm inferring then that you just add zeros? I'm learning as we go. I would have figured that out if it said x10K on the scale but the 20 confused me.

-AJ

Quote from: DIY Bass on June 22, 2020, 02:06:55 AM
I am a bit suspicious of C14.  You could remove it and see what happens to those voltages.  It acts as a filter on the power supply, so without it the circuit would still work perfectly well.

I can try that. I'm guessing with the tests we are doing I should expect 9V from the +9V to GND and so the 1.5V I got is really off?

I don't see anything labeled continuity on my meter So I don't know what setting that is.


I'll go over the back of the board with a magnifying glass. Back when I soldered in college we used to scrub our joints with a stiff brush and 1,1,1, trichloroethylene. Sometimes we'd use a dunk tank. Made all the joints nice and shiny. Should I be doing this?

I'll check the joints and if I don't find anything I'll remove that C14 capacitor and check the voltage from +9V to GND again.

Thanks!

-AJ
(https://i.postimg.cc/dLVdkdBS/IMG-20200622-120826.jpg) (https://postimg.cc/dLVdkdBS)

I don't see anything to my unpracticed eye under the magnifying glass that look like bridges. I also double checked the tantalum capacitors and all off the + signs printed on the capacitors line up with the + signs printed on the board. This is C14.

(https://i.postimg.cc/d7ZWcGCf/IMG-20200622-111805.jpg) (https://postimg.cc/d7ZWcGCf)
Oh, and I checked, all of the diodes have the stripe on the square hole side.

-AJ

> Probably the cost for remarking the IC is bigger....

I think in many Asian factory towns, parts-printers are as common as staplers are in offices. Bring thousands of chips in your lunch-bag, remark them over lunchtime or after quitting time.

The continuity mode is the one with a diode symbol. It'll probably beep when you touch the probes together, and show a value like 0001. It's useful to test if things are shorting together, and we already have symptoms of +9V and gnd being shorted somewhere. The voltage dropping a lot and the battery getting hot shows that's happening.

The 20K indicator means you can measure resistors up to 20K within that range. If you have a 22K resistor, you won't be able to measure it, the multimeter will probably just show a 1 or something like that, and you have to move to 200K range to measure the resistor. You can do the test to check by yourself. Also, why don't just use the 2M range to measure let's say a 1K resistor? The difference is the resolution you'll have. On 2M range, it'll just measure 1K (0.001M). On the 2K range, you'll get a more precise value, useful for circuits that you need a very precise resistor (don't worry on that for guitar circuits).

Looking at your photos again, I can notice something. Your +9V wire is soldered in a ugly and exposed way. You should correct it to be as the other 4 wires near the switch side of the board. I mean, the wire should go thru the hole, and the insulation should be touching the board. I can't be more clear than that, since english is not my main language. It may not be related to the issue (or may be), while you correct it, do another test: disconnect the wire from the board, power the circuit and measure the voltage directly to this wire. Red probe to the wire, black probe to ground (which can be any ground point, like the ground connection of the switch, the nut of the jack or any point of the enclosure itself.

Ahh. I thought that setting was for measuring diodes. Gotcha!

I will fix that wire so it isn't sticking up high. But make sure I understand, remove the wire connecting the DC jack to the board at +9V. Then put the red test lead on the wire end and the black test lead on GND? So the jack will not be connected to the board at 9V? Correct?

This setting does measure diodes, but also measures continuity between two points (very helpful to check if two thinks are connected together and to find unwanted shorts) and way low resistence (some circuits uses resistors like 0.1r or even smaller than that).

And yes. Remove the wire from the board. Then do the usual procedure to be sure the dc jack isn't touching the enclosure, power the circuit and measure the voltage with the red probe on the wire and the black probe on gnd. It may be a shot in the dark, but by doing this we can check if the short is on the board or on the wiring.

Also, I have something else on mind, that may be related to this last test. Could you take a photo that shows how you're wiring the dc jack?

Thanks for teaching me.

Here's the jack that I soldered back up outside of the case so it doesn't touch. The battery is a little spent now, 8.28 volts. With the red test lead of the red wire and touching black to GND I get 8.28 volts. Actually -8.28.volts. I don't know if the negative is important.

(https://i.postimg.cc/VJ8PDh9H/IMG-20200622-191011.jpg) (https://postimg.cc/VJ8PDh9H)

Well...

Quote from: ajhuff on June 22, 2020, 08:14:57 PM
Actually -8.28.volts. I don't know if the negative is important.

That's what I was suspecting on the last post! You wired the dc jack the wrong way, with positive connected to the center instead of negative. Even with the dc jack not touching the enclosure, you're shorting the battery wires. D3 is wired as a reverse polarity protection. If you use the correct polarity, it won't conduct, and the current will flow to the circuit. If you reverse the polarity (what is happening), it will conduct and send the current to ground, so it doesn't damage the circuit.

So let's fix your build. Reverse those two wires, with ground (the green one) soldered to the center. Remember you're still using a metal jack, so it can't touch the enclosure. Remove all the ICs again. Power the circuit, measure voltage between +9V and gnd pads. It should be +9V (I will just round up the number).

If it's +9V, turn off the power, put IC3 back, power it on again. With black probe on gnd, measure pins 4 and 8 of any other IC socket. It should be -9V and +9V. If yes, turn off the power again, put the ICs on their sockets, plug your guitar, turn power on again, and hopefully you'll have a working pedal to play with.

I had no idea! That was another instruction I had to guess on.

Now I get +9 volts between +9V and GND!!!

But on socket pins number 4 and 8 on both of the empty sockets for IC1 and IC2 I get +4.8V and -4.8V

Specifically, negative voltage on 4 and positive voltage on 8 on both sockets. I am numbering them like this.

1 • 8
2   7
3   6
4   5

I googled that. Hope it's right.

Ok, so we solved part of the problem. Good news.

On the voltage, yes, negative voltage on pin 4 and positive on pin 8. Your pinout is correct. But there should be 9V, not 4.8. While it will work with those voltages, let's check what's happening.

Check the voltages on both sides of D4 and D5. Also, check the voltage where R20 and R21 are connected together. You've already used that point to check resistence.

I'm sorry for being so basic, but when you say check the voltage on both sides of the diode, where do I put my test leads? From the +9V to each side of the diode? Or from the diode to the GND? Or a test lead on each side of the diode?

-AJ

Black probe on gnd. You'll often see people posting voltages or asking for them, they're almost always with the black probe connected to gnd.

For D4 the voltage is 4.85 on the the non-stripe side, 4.3 on the stripe side.
For D5 the voltage is -4.1 on the non-stripe side, -4.3 on the stripe side.
For R20/R21 the voltage is 2.4.

-AJ

Your voltages are technically right. Taking D4 voltage as the "main voltage", voltage on D5 should be around the same but negative, while voltage on R20/R21 should be about half.

The strange thing is the non-stripe side of D4 is directly connected to the +9V pad, so you coudn't have different voltages on those places.

Check those 3 voltages again, just to be sure: voltage for +9V pad, voltage for non-stripe side of D4 and voltage for the battery measured directly at the battery, unplugged from the circuit. They should be the same.

Fresh battery for best case. Battery voltage is 9.26.
From +9V to GND is 9.25 volts.
Form non-stripe side of D4 to GND is 5.42 volts.

-AJ

That's really strange. Maybe something is wrong in the documentation?

Let's try another two things:
-First, check continuity between +9V pad and the non-stripe side of D4. You don't need power for this one. If there's no continuity, reflow the solder joint (melt the solder joing again and add just a little bit of solder), then test it again.
-Then, if you got continuity, remove IC3, power the circuit and check the voltage on the non-stripe side of D4.

The meter reads 1.74 between +9V pad and the non-stripe side of D4. Does that mean continuity?

Does it beep when you do this test? Does it beep if you touch the probes together? We should figure out how your multimeter reacts to continuity first, before doing the test. My bad on that.

After you figure how your multimeter reacts when both probes are touching, check for continuity between +9V pad and those stuff: non strip side of D4, strip side of D3, the other terminal of R20 (not the one you used before, that's connected to R21). You don't need power to check them. It may looks like a few random tests, but that's how I can try to find out what's happening on the power input part of your board without having it on hands.

I got it! Yes it beeps. I was  not on the +9V pad. So I have continuity to D4, D3, and R20. With IC3 out I have 9.25 volts at D4! I may have been on the LED pad next to the +9V pad before. Sorry.  :-\

Don't worry, it happens. Then, if it beeps, everything seems to be fine with the board.

So we isolated the problem to the voltage inverter (IC3) part of the circuit. Check again if C16 and C17 are correctly oriented. I've checked the other ones.

Power the pedal without the ICs. Measure voltage on +9V pad and both sides of the diode. They should be very similar. Then turn off the power, put IC3 back (just IC3) and measure those same voltages again.

If there's a big difference between those voltages, and the caps are correctly oriented, then there is something wrong happening when you're putting the IC. So, if that happens, turn off the power, then check the continuity between every pin of IC3 with it on the board. With one probe on pin 1, put the probe on each other pins. Then move the fixed probe to pin 2 and test all the other pins. Let me know which pair beeps (1 and 8 should beep).

Oh, I forgot. I went back and tested the 4 and 8 pins on the empty sockets like you asked up above, now I get full voltage!

-AJ

I'm getting close to full voltage on the diodes with IC3 plugged in.

-9V on pin 4 and +9V on pin 8? Then now it's time to put the ICs back and enjoy your pedal!

What was going on? Nobody knows lol but maybe it was some invisible solder bridge somewhere, that you ended up scrapping with the tip of the probe while you did the measures, or some dirt/oxidation on the IC pins.

I'm sure it was my lack of understanding of the metal jack, the two diodes soldered in wrong, and a whole lot of learning how the meter works. I'll get it buttoned up and report back. Thanks!

-AJ

It was related to the metal jack. But the diodes aren't part of the problem. Since they're for clipping, if you got the circuit working at first try, you won't get a distorted sound.

But anyway, let us know how it goes.

Hah. Well we spoke to soon. My plastic jack from Mouser came today. Kobiconn 163-4302. I can't  understand how it gets wired. I've tried two combinations so far and in both times I don't get any voltage between +9V and GND. I did all the checks like we did before. And the battery got hot. I'll try again tomorrow. The metal jack only had two connections so it was easy when you told me to switch them. This one has three. I guessed wrong twice in a row.


Also, maybe it's not significant but the battery plug went into the metal jack all the way flush. It doesn't on the plastic jack. Might be an 1/8" still to go.

-AJ
(https://i.postimg.cc/0MgJ28Pk/ITP-163-4302-E.jpg) (https://postimg.cc/0MgJ28Pk)

(https://3.bp.blogspot.com/-9ZtuweiNtOU/WqERrmSdWdI/AAAAAAAAFlU/r6zmOwzalOwDMjI8az_6-WxCWsvSXHDbgCLcBGAs/s400/DC-Jack.png)

I must confess I don't know the exact pinout of this kind of jack :icon_redface: :icon_lol:. It's the pinout Willienillie posted. What I do is I know the "dotted" pin is connected to the center pin, so it's negative. For the other two, I know one is for battery +, other is for board V+. Both are for positive, I just jump them together and connect them to board V+ since I don't use batteries at all.

For the plug not entering flush, some of these jacks have thinner central pins, while other have thicker central pins. The same goes for the plugs, some of them have larger holes.

Quote from: willienillie on June 24, 2020, 02:52:59 AM
(https://3.bp.blogspot.com/-9ZtuweiNtOU/WqERrmSdWdI/AAAAAAAAFlU/r6zmOwzalOwDMjI8az_6-WxCWsvSXHDbgCLcBGAs/s400/DC-Jack.png)

That was the secret hand shake! Thank you. In my unskillmind I thought power came from the middle. Learning a lot here!

-AJ

OMG!!!! It works! It actually works! I can't tell all of you how much I am grateful for your patience. I was overwhelmed and distraught about to give up when I searched Google and found this forum. I sure learned a lot. I'm not sure I'm up to doing another one but I know I couldn't have done it without you. Especially Marcos.

Thanks!!!!

-AJ

(https://i.postimg.cc/JGkdfzfQ/IMG-20200624-122832.jpg) (https://postimg.cc/JGkdfzfQ)

Nice to hear it's woking! The best thing is you didn't gave up, so we could work on the effect until finding what was wrong. And you'll surely will do another one sooner than you think :icon_twisted:

Quote from: ajhuff on June 23, 2020, 11:31:31 PM
I can't  understand how it gets wired. I've tried two combinations so far . . .

Quote from: ajhuff
I thought power came from the middle.

Guessing isn't a good strategy.   ;)   Read the datasheets if you're unsure.  You should be able to find datasheets for everything, including DC jacks.  If you can't get a datasheet for something you're going to buy - and it's not obvious - then don't buy it; you'll just be inviting grief.

But good that all is working now.  As you say, lots of learning on the way.  Don't stop doing that.  :)