# Op Amps and Power



## burger-patty-and-bacon (Jul 29, 2021)

Super noob question.  I just finished my second build but like a noob, forgot to order the OP AMPS on the original buy so I had to buy them after and they will come tomorrow.  So my pedal is 99% done with slotted IC holders to put the op amps into once they land.

Question.  I went to test (with no op amps installed, it needs 4).  Would not having the op amps installed cause the pedal not to power on?

It is the Dirty Sanchez.  Thank you.


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## Robert (Jul 29, 2021)

The LED should light and you should still have sound in bypass.

Otherwise it won't do anything else.


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## burger-patty-and-bacon (Jul 29, 2021)

No LED coming on.  have in and out cable connected, DC power.  no LED comes on.  It's fully built sans the 4 op amps I need...  Shucks.

Get sound in bypass.


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## Mcknib (Jul 29, 2021)

Check you've got power going in on the power + and - pads


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## burger-patty-and-bacon (Jul 29, 2021)

Mcknib what setting on DMM to use I use to check power coming into the + and - on the PCB?


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## Mcknib (Jul 29, 2021)

20V DC putting red probe in V voltage and black in COM / ground then just stick yer red on + and black on -


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## burger-patty-and-bacon (Jul 29, 2021)

My DMM is "auto sensing" and can pick up whatever I measure. So for POWER, yes I am getting power into the jack itself and also getting power to the PCB in the - and + positions.  The reading is 22.5. So yes, power IS coming in.


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## Mcknib (Jul 29, 2021)

Post a pic so we can see how you've got it set up

I've no idea what voltage it should be looking at the schematic I thought it was 9v I'd assume you've got caps rated for over that 

Check what voltage you get cathode of D100


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## burger-patty-and-bacon (Jul 29, 2021)

Mcknib said:


> Post a pic so we can see how you've got it set up
> 
> I've no idea what voltage it should be looking at the schematic I thought it was 9v
> 
> Check what voltage you get cathode of D100


Here are two pics.

I switched my DMM to read as DC VOLT.

Reading on my DMM at the black and red lugs of the DC power innie jack is 9.25VOLT

Power at the CATHODE side of D100 when touching ground of DC jack is 9.33VOLT


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## Mcknib (Jul 29, 2021)

That's ok powers going in check your LED is orientated correctly and you've got voltage on the CLR R107


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## burger-patty-and-bacon (Jul 29, 2021)

I'm gonna be pretty beefed if I put the LED in backwards.  =(  I will have to dismantle pretty thoroughly to get to it.  I soldered it, shrunk wrapped it, glued it and its' under the board.
I did use a coin cell battery from the back side just to TEST the LED and it glows nice and purple so I know the LED is good.

When you say "CLR R107", i know where R107 is but what is CLR?  I need to hold black probe to ground and red probe to either side of R107?  I am a noob, I do not know what CLR means.  BLESS YOU!  EDIT:  GOOGLED.  CURRENT LIMITING RESISTOR.

EDIT:  Getting 9.49VOLT at the R107, either side of it.  Red probe at that resistor and black probe on the ground of DC jack.


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## zgrav (Jul 29, 2021)

touch the leads of another LED to each contact point on your LED to see if it lights in either arrangement of the two leads.  I usually leave the LED unsoldered on a board until everything else is done to make sure I have it oriented correctly.


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## Mcknib (Jul 29, 2021)

I've had to go back to work but I think you can use your meters diode function to check LED polarity touch the LED legs with red and black probes if it lights briefly with red on anode and black on cathode it's correct if not it's the wrong way round


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## burger-patty-and-bacon (Jul 29, 2021)

I just totally redid the LED wiring and I put it into a bezel. 
Red wire to A for ANODE / POSITIVE and black wire to K for cathode / NEGATIVE.
I can get LED to light up with I touch either side of the board with some small leads and a CR2032 batt (handy trick).

When I power the unit, NO LED comes on.

Getting DC power at hte various places asked, the D100 diode and the CLR R107.  9+V at each.  Clearly power coming in and this was a super clean build since I really took my time and did it clean...  I will wait for the op amps to come in and maybe when they go in, it will light the LED?  darn slow USPS.


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## burger-patty-and-bacon (Jul 29, 2021)

Beginning to suspect stomp switch possibly.  What can I do in order to test it?  I have it soldered to a PCB I/O board.


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## Mcknib (Jul 29, 2021)

So you've verified that your LED anode + leg goes to the A pad and cathode - to the K pad

Just to double check you get the same voltage both sides of R107?

One side you should get the same as D100 anode 9v ish the other around 2.5V


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## burger-patty-and-bacon (Jul 29, 2021)

Yes.  100% absolutely the LED is wired right and I know LED is good bc I tested with cr2032 coin batt.  Completely rewired it and have it in a bezel now.


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## Mcknib (Jul 29, 2021)

Yeah coin cell is as good as yer meter diode function to suss orientation if you put the + of the battery on the pin going to A pad and - on pin to K pad and it lit it's correct orientation 

So you could be correct with it being the 3PDT connections check your SW and GND pads maybe just reflow them both ends 

You can continuity check from SW and GND pads on the main pcb to the 3PDT lugs 4 and 5 top two on the middle row


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## burger-patty-and-bacon (Jul 29, 2021)

OK!  GOT MY OP AMPS.  Slotted em, PEDAL IS WORKING.  HAVE SOUND FROM PEDAL WITH OP AMPS NOW.

However, still no LED.  WIll  try this next:

So you could be correct with it being the 3PDT connections check your SW and GND pads maybe just reflow them both ends

You can continuity check from SW and GND pads on the main pcb to the 3PDT lugs 4 and 5 top two on the middle row


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## Mcknib (Jul 29, 2021)

Make sure they connect as shown and middle lug 5 connects to ground and those 2 lugs 4 and 5 have continuity in effects mode

SW should also have continuity with LED K pad

What happens is switched to effects mode middle and top rows connect you're connecting your signal from in jack to circuit in through the circuit to circuit out and out jack at the same time connecting lugs 5 ground to lug 4 grounding your LED cathode and lighting it to indicate it's in effects mode

So once you continuity check it you'll know if it's all connected as it should be now that you've checked everything else it must be a poor connection to ground


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## burger-patty-and-bacon (Jul 29, 2021)

I am using PedalPCB breakout board though.


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## Mcknib (Jul 29, 2021)

burger-patty-and-bacon said:


> I am using PedalPCB breakout board though.


Doesn't matter it connects the same

If you continuity check the SW pad on the main pcb it should beep with LED K pad and 3PDT lug 4, 3PDT lug 5 to ground and in effects mode 4 and 5 should have continuity


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## burger-patty-and-bacon (Jul 29, 2021)

Having a hard time following.  Every line you drew should beep with continuity?  Does this go

123
456
789 ?

SW to K pad of LED does NOT BEEP.


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## Mcknib (Jul 29, 2021)

Like this

I keep forgetting yer new you pick stuff up pretty quickly 

Anyway so 3PDT lug 4 continuity with SW and SW should also have continuity with LED K 

Lug 5 to ground

And with effect on lugs 4 and 5 should have continuity


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## burger-patty-and-bacon (Jul 29, 2021)

Mcknib said:


> View attachment 14246
> Like this
> 
> I keep forgetting yer new you pick stuff up pretty quickly
> ...


LUG 4 has continuity with SW on the PCB breakout board and on the main PCB itself.
SW on PCB breakout (which is on top of footswitch) does NOT have continuity to the K PAD of the LED.  (Or the A pad of it).  In either clicked position.


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## Mcknib (Jul 29, 2021)

SW on the main pcb should have continuity with LED K pad

Reflow your SW on the breakout board

We know you get power to the LED when you switch to effect you should have continuity LED K to SW then to breakout SW and lug 4 which connects to 5 

Check your ground side wiring isn't touching anything and your LED legs aren't touching any bare metal or each other


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## Mcknib (Jul 29, 2021)

You want continuity like this in effects mode when checking continuity don't do it on the wire jumper ends touch solder pads and 3PDT lugs, do 3PDT lugs 4 and 5 have continuity in effects mode?

Basically when in effects mode all of those connections from LED K pad through to lug 5 should connect to ground you've got a trace from main board K pad to SW then a jumper SW to  breakout SW to lug 4 to 5 to ground turning the LED on then when switched to bypass it breaks the ground connection and turns the LED off

It's simply a process of elimination far better than randomly removing things, you know SW breakout connects to lug 4 and main SW, no connection SW to LED K so check nothings causing a short touching bare metal etc and reflow solder joints, check lugs 4 and 5 connect and check 5 connects to ground


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## burger-patty-and-bacon (Jul 29, 2021)

Reading now, had to leave for a bit.  I get no beep from SW on PCB to K of LED.
Since this is not beeping, do I need to do a direct jumper from K pad to SW?
Or can I jumper from pcb breakout SW direct to K of LED?

"do 3PDT lugs 4 and 5 have continuity in effects mode?"  YES, they do.  I don't know when I am in effects mode, but in one instance 4 and 5 do not beep, then when i click, they do beep.  I now know that when 4 and 5 beep I am in "effects" mode.
LUG 5 beeps to ground.

DEFINITELY seems the issue is the K of LED not beeping to SW on PCB.  Please confirm if OK to jumper those?


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## burger-patty-and-bacon (Jul 29, 2021)

Mcknib said:


> Doesn't matter it connects the same
> 
> If you continuity check the SW pad on the main pcb it should beep with LED K pad and 3PDT lug 4, 3PDT lug 5 to ground and in effects mode 4 and 5 should have continuity


This makes ALL the sense now, ha.  
SW on PCB to LED K, no beep. 
3PDT lug 4 to SW pad on PCB, BEEP. 
3PDT lug 5 to ground, BEEP.  (in both modes)
In effects mode, 4 and 5 BEEP.  When not in effects mode, 4 and 5 no beep.

For sure it is SW PAD on PCB to LED K no beep!  Amazing way to deduce this, just not sure how to fix that.


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## Mcknib (Jul 29, 2021)

Hold a piece of wire on the connections see if it lights up if it does install the jumper if you've already tried reflowing those pads

I'm assuming all ppcb boards connect like that I checked on a conqueror supreme board all 3 LED K pads connected to their SW pads


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## burger-patty-and-bacon (Jul 29, 2021)

this will be a very tricky feat with liam neeson level skills.. attempting this now.


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## Mcknib (Jul 29, 2021)

burger-patty-and-bacon said:


> this will be a very tricky feat with liam neeson level skills.. attempting this now.


No swearing now, just whack a jumper on if your LM skills are lacking I've got wee clippy wires so no skills required

Remember an LEDs a diode so don't hold your iron on it or it's pad for more than 4ish seconds


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## burger-patty-and-bacon (Jul 29, 2021)

I made a CANDY CANE hook end out of a SMALLLLLLLLLLLLLLLLL piece of bare wire, SOMEHOW used tweezers and my stew mac tools, SOMEHOW got it in there, somehow soldered it.  Keep in mind, I have this PCB and switch DIRECTLY on top of the PCB.  This is not an easy access.  That was like MICRO SURGERY right there.  And guess what!!!!!!!!!!!!!!!!!!!!!!!!!!


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## burger-patty-and-bacon (Jul 29, 2021)

yet ANOTHER pedal fixed by the WIZARDS on this forum.  A M A Z I N G !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

just wow wow wow you guys are GOOOOOOOOOOOOD


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## Mcknib (Jul 29, 2021)

burger-patty-and-bacon said:


> I made a CANDY CANE hook end out of a SMALLLLLLLLLLLLLLLLL piece of bare wire, SOMEHOW used tweezers and my stew mac tools, SOMEHOW got it in there, somehow soldered it.  Keep in mind, I have this PCB and switch DIRECTLY on top of the PCB.  This is not an easy access.  That was like MICRO SURGERY right there.  And guess what!!!!!!!!!!!!!!!!!!!!!!!!!!


Jaysus hope you've got yer aviators on that's bright as.......well done to you

You actually had the circuit working first time just no LED indication and for starting out I'd say that's a pretty good record so far

As you go on and learn this stuff you'll realise it's fairly simple no special wizard powers needed


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## burger-patty-and-bacon (Jul 29, 2021)

Mcknib said:


> Jaysus hope you've got yer aviators on that's bright as.......well done to you


THANK YOU MAN!!!!!!!


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## burger-patty-and-bacon (Jul 30, 2021)

Mcknib said:


> Jaysus hope you've got yer aviators on that's bright as.......well done to you
> 
> You actually had the circuit working first time just no LED indication and for starting out I'd say that's a pretty good record so far
> 
> As you go on and learn this stuff you'll realise it's fairly simple no special wizard powers needed


I guess the question is why was the PCB itself not beeping/continuity from SW to LED K...  Very interesting.  

Thanks again for the amazing help, sir. 

Because of the forum and the help provided, I will buy all of my PCB's from this site exclusively.  On that note, USPS delivered board #3 to me yesterday I'm just waiting on Tayda for the guts.

Next pedal is the Greengage (Plumes clone).


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