Hi guys, major taplfo problems here :/ My tap tempo cardinal is sitting on my bench for a month as I am unable to get the LFO part working at all. Jon has been a great sport and helped me a lot to try and debug it but we came to a conclusion that my TAPLFO is simply not working so I bought another one (ouch!). And that one isn't working either.
Basically I've got this thing on my breadboard
(http://www.electricdruid.net/images/lfo/TapClock.gif)
cause I am trying to get the LFO working but it ain't happening. It just won't oscillate. I bought one from Banzai Music and the other one from Musikding, both are from Germany. I bought my crystal from Banzai too. Could it be the crystal?
Here are my voltages for the LFO pins (depth at max, all other controls half-way up):
2 - 2.17 V
3 - 2.39 V
4 - 5.02 V
5 - 0.51 V
6 - 2.19 V (someslight oscillation from 2.18 to 2.21 but that's probably my multimeter)
7 - 2.18 V
8 - 5.05 V
The other taplfo chip I received shows 0.03 on pins 6 and 7.
It's a total mess. I can't believe this. Any thoughts guys? I would really like to finish this and put it on my board :/ some other tests I could do? Is it possible that I got 2 dead-on-arrival taplfos? I can't be that unlucky. I did not abuse them, they should be in good operational condition.
Thank you for any help you might provide. Cheers.
Just so everyone knows, this one has me stumped.
When you get a chance, maybe take a picture of the breadboard, but IIRC your voltages are identical between the board and the BB.
Have you tried connecting pin11 to ground via a 1k resistor? Pulling pin11 up to 5v might be making the rate too fast to detect. Just a guess.
I actually have one of these on my bench also that I am finishing up for a friend. I will take some reading from mine also if you like. I think I just need to put some pots on it and its ready to go.
When I was building one of Rolo's PCBs (Can't remember if it was my Twin Peaks or the liquid mercury) I had issues with my TAPLFO also. I knew the PIC was good since I programmed it myself and I was then able to read it and CRC check it to the HEX. It actually ended up being my crystal that I swapped out and mine came to life. I am not 100% sure if that was exactly fixed it but it is sure worth swapping out. I had a couple 20 MHz crystals that I had no idea where they came from so I ended up getting a bag of them from Tayda and they seem to unction just fine. I have built 4-5 TAPLFO pedals with out issues with them.
Hope you get it going man.
Cody
I've got my taplfo chips programmed from uk-electronic, also from Germany. One of the crystals I also got there, the other one from tayda. Both seem to work fine.
Do you have a scope that you could try to measure the output with? might just be it oscillates but at too high frequency or too little depth. Frequency issues could be caused by the crystal for sure as it's the reference point.
good luck, it's an awesome pedal.
Thank you so much guys, the support means a lot as I am very discouraged by this :/ I am lusting for this pedal so will continue to put the effort for sure.
This is the crystal I use - http://www.banzaimusic.com/Quartz-Crystal-QM020.html
And no, I don't have a scope :/
@Brian, I will try that!
@Jon - I could send you a picture of my breadboard but I feel you will get a headache if I do! I used those probes and like 20 of them so the whole thing looks like a rat's nest, but since I am getting the same voltages like on the pcb I am guessing I have done it right.
I think a picture, however rats-nesty it might be will be useful.
So you are building the "Drum machine/sequencer clock" circuit, looks simple enough (which usually means "many possible routes to less than obvious failure")
"This example circuit provides tap-tempo +5V clock pulses for driving analogue sequencers or drum machines. R3 to R8 disable the waveform output (fixed to Ramp Up), the multiplier (fixed to x1), the output level (fixed to max), the pulse width (fixed to 2.5V, square), and the 'Next multiplier' input (tied high). The main LFO output isn't used. Tempo can be set either by the Tempo knob VR1 or by tapping the button."
(http://www.electricdruid.net/images/lfo/TapPinoutV2.gif)
I assume you're getting a good 5V in at pin1? (Pin 8 is the multiplier and showing 1x, so that looks fine.)
Does pin 4 zero out when you tap?
6 and 7 should be oscilating between 0 and ~2.5 when the thing is on, if its a constant reading it is possible its oscillating too quickly to read, I suppose.
Is pin 5 connected to anything?
Quote from: somnif on August 11, 2016, 10:56:04 AM
I think a picture, however rats-nesty it might be will be useful.
https://drive.google.com/file/d/0B--6F_4JB7SYajM4amx0eEF0Qm8/view?usp=sharing
I don't think I can shoot this in a way that'll make it presentable :/ the crystal is on the left as I removed it from the pcb.
QuoteI assume you're getting a good 5V in at pin1? (Pin 8 is the multiplier and showing 1x, so that looks fine.)
Does pin 4 zero out when you tap?
6 and 7 should be oscilating between 0 and ~2.5 when the thing is on, if its a constant reading it is possible its oscillating too quickly to read, I suppose.
Is pin 5 connected to anything?
I do get 5V on pin 1.
Pin 4 zeroes out when I tap, yes.
5 is not connected to anything, on pin 6 I get 1.47V flat. Then I stepped away from the breadboard to have some lunch, got back, measured the voltages again and I was getting flat zeroes on pins 5,6,7. Now I can't even get 1.47 like before. Great. Just... great.
Whats up with the resistor off pin 7, it looks twisted around?
It's just warped like that as I couldn't push it into the breadboard socket easily, but it connects ok. It's a 1K for the LED, I tried it all without that resistor as well and it's the same as one would expect. It says 20.000 Mhz on my crystal, that's ok right? Just triple-checking, as I am desperate.
Ah I asked about the twist because I thought it might be shorting past the resistor straight to the LED.
How are you "tapping"? Is there a button off screen, or are you just tapping a jumper to ground? (I'm guessing its the blue wire slightly pulled out the ground rail but its 5:45am and I take nothing for granted at this hour)
Is the pinout on the trimmer the right way around? its a bit hidden behind some wires.
Lets see....
Hehe yes the blue wire hanging is the one that I tap to ground, and yes the trimpot is oriented correctly.
Feck it man, I just ordered a 3rd taplfo from a source from which Brejna confirmed it worked for him (same source Felix mentioned). If that one doesn't work Imma cry.
Quote from: Cortexturizer on August 11, 2016, 12:11:43 PM
5 is not connected to anything, on pin 6 I get 1.47V flat. Then I stepped away from the breadboard to have some lunch, got back, measured the voltages again and I was getting flat zeroes on pins 5,6,7. Now I can't even get 1.47 like before. Great. Just... great.
Don't panic. It's not
worse than before. Those are the output pins, they just show the voltage that the chip tells them to show.
The root problem is that it doesn't seem to be OSCILLATING. The actual voltages on those pins vary when the chip is working as it should. If something triggered when you weren't looking, they could have just gotten stuck at ground instead of stuck at 1.7V or whatever. So again, don't panic :)
You mentioned you pulled the crystal from the PCB -- did I missed that this was your only 20MHz crystal? I'm not sure how a crystal can get damaged or broken, but I'd absolutely swap it out. I've used the ones from Tayda without issue, though I think I would buy more than one or two of them just to be safe. I'd send you a couple but I have a feeling that shipping from Tayda or Banzai is a lot cheaper.
I had a look at the breadboard and despite the wires all over the place, I don't see anything amiss.
Ninja edit: Dude, don't order another TAPLFO. The chances of two of them being bad without trauma is extremely small.
I wonder if you could rent/borrow a DMM with a frequency meter for an hour or two somewhere. I know you can rent power tools at home depot, wonder if they have electrician supplies... Heck you can probably buy one for about the price of another LFO chip I bet. DMMs with it are about 15$ on Amazon, I'd wager a cheapo freq counter on its own would be about 10$... somewhere.
Edit:
Ok lack of sleep is catching up with me, DMM freq testers cap out in the kilohertz range, not Mhz, duh. I shall keep thinking...
http://www.electronicecircuits.com/electronic-circuits/crystal-tester
If you have a bit of time on your hands you can try cobbling this together to see if your Crystal is still functional. If you dont have BC550s, 2N5088s would probably work just as well. If its working, LED lights. If no oscillation, no light.
edit: note may want to use a dim diffuse LED or up the ohms on R3 depending. Tossing in a waterclear with only 560 on the CLR would likely blind you....
Thank you for the crystal tester, I will give it a go!
QuoteNinja edit: Dude, don't order another TAPLFO. The chances of two of them being bad without trauma is extremely small.
Brejna told me that he ordered several from another guy from Germany and it wasn't until he got one from the place I just ordered from that he got his Cardinal working. Who knows, maybe some contingent of bad ones got to Germany or whatever...
As for the crystal, I just saw that there are some locally, in Belgrade. Lol. I will go there after work and get me some. We'll know more afterwards.
I really hope it's just the crystal. If it does turn out to be the chip, I'd raise hell with whoever charged you E10 a piece for them.
Not the crystal. Changed it, and it's the same. Bloody hell.
Ok, so I thought of the slight possibility that I may have f-ed up something on the breadboard and since I haven't tried the combo of the new crystal and the new taplfo on the pcb at all I tried that and the frickin thing works now!!!!!! It works as it should from what I can tell. Will get back to you guys soon with a confirmation but it looks like it's working well now.
Jesus. Finally :D
It's always the last thing you think of...
:)
well, that's how it goes. Good to hear you've got it working. Odd that you've got a damaged crystal and chip at the same time. uk-electronic is a good shop for sure. same quality as musikding with fast turnaround times.
woohoo!
Kudos for plowing through and not giving up. I can only hope that the design is good enough to have justified the frustration in building it.
Quote from: midwayfair on August 11, 2016, 07:59:10 PM
woohoo!
Kudos for plowing through and not giving up. I can only hope that the design is good enough to have justified the frustration in building it.
I can vouch for it. It is worth it. It's a wonderful effect, Jon. From subtle to choppy. it covers everything.
I think this calls for a demo ;)
Awesome!
Thank you lovely people!
I still haven't tried the old chip on the pcb, it might work! If it does then it was the crystal for sure. But right now I am ultra happy to just have it going.
Jon, it sounds pretty good although I am not sure if I have it at it's best still. I have yet to revisit one of your demo videos to get used to the sound some. For now, I was floored by how much difference the Balance and Waveform controls make, I expected them to be subtle but man they can make or break the sound. Is this what they are supposed to be like?
As for the two LEDs, they are 3mm red and green diffused, correct? I don't have 3mm leds right now, only one red so I put one 5mm green in there just so that the effect would work. They have to be of a certain type so that the effect would be at it's best right?
EDIT: Saw your video in the meantime, well mine sounds pretty much like that. Just gimme some advice on the two LEDs and I'll be off to box this baby! Woohoo!
I did notice a bit of distortion on the dry signal, but I think I had volume above unity all the time, and in the Bright mode it's no wonder to have some right?
The waveform makes a gigantic difference in harmonic mode. The smooth waveforms are best for that mode. The balance is more for fine tuning in that mode but necessary for really blippy tremolo.
If you aren't using the bicolor LED use red for both (unless they're already soldered in which case what you have is fine). Red/green is just the closest I could get in a bicolor to matched forward voltage -- way better than red/blue for instance.
Quote from: midwayfair on August 11, 2016, 09:44:37 PM
If you aren't using the bicolor LED use red for both (unless they're already soldered in which case what you have is fine). Red/green is just the closest I could get in a bicolor to matched forward voltage -- way better than red/blue for instance.
Great info, thanks Jon. I hope to finish up mine this week also.
Cody
Playing with it some more I noticed that my Waveform control only works to half-way up and then after 12 o clock, regardless of the mode I'm in, nothing happens. Is this normal? The pot is a dual B10K pot.
I also biased Q1 to 7.5V as 6V had been giving me distortion on my high output SG pickups. Sounds spongier, not necessarily worse. Will have to spend some more time with the pedal to know which bias I like more.
are you getting random mode at all? What waveforms are you definitely getting?
Why are you using a dual pot? if you use a concentric one, you'll be my all time hero... I should have thought of that building mine... I've got balance and volume internal, but rate external ??? ???
I would check voltages on the chip as you turn the pot. I think the tapLfo documentation has a section about when the chip is switching waveforms.
Ugh, I feel like I am losing my knack for pedal building as I am making more and more premature conclusions - the waveform is fine, I just had the Balance all the way to the right so some of the waveforms were pretty imperceptible with Balance set that way. It all works fine and is ready for boxing! Woo-hoo! :)
Thank you gents so much. I persevered, but only because of your support, I have less and less patience these days, but I really wanted this and boy did it pay off. Fantastic pedal Jon! Amazing sound, goes straight to the board.
Cheers gentlemen!
Did I mention that the old TAPLFO works just fine?
Feck man. Now I will have 2 of them that I don't need, when the 3rd one arrives.
So the conclusion of the story is - it was the crystal. Fecking hell.
Oh well...
(http://www.leeabbamonte.com/wp-content/uploads/2015/03/Beer-1.jpg)
I did the same thing with the balance or wave distortion control. So you have company in the dumb mistake category :)
I still need to figure out how to get the tap led to work correctly- I want to have an indicator that is straight tempo and it doesn't seem to work when I have tried it before
Sent from my iPhone using Tapatalk
I need a tapflo, I'll buy one from you as long as shipping to the states isn't ridiculous.
Quote from: Cortexturizer on August 12, 2016, 09:42:53 AMI just had the Balance all the way to the right so some of the waveforms were pretty imperceptible with Balance set that way
Pft, I did that when building the prototype. And the second prototype. I also used to forget to check the wave distort knob when I set up my board at gigs and something was wrong.
If it wasn't so useful in the full-range tremolo mode, it would have been fixed resistors. :)
Can't wait to see the finished product. Your enclosures are always spectacular.
Heh, yeah that's my fear as well, that I will constantly move something accidentally, but I do agree that they are needed to use the pedal to it's fullest. Great tremolo, really just what I wanted. Harmonic mode can do some whacky sounds as well, not something that I will use but it could come in handy.
I am going for a 1590B, because you know me, I love it when it hurts! Hah!
I do have more for the troubleshooting crew though. It seems that every pedal I make distorts when it shouldn't. I have my beautiful PS1A doing that as well as my Loophole. God if I could get rid of that distortion that would make me so happy. Gotta start the threads for that as well I suppose. I count on you gents to help me with that!
Tell you what, I'll PIF the other 2 tapflos. Feck it, your help gents is much appreciated and I often need it, so it all levels out lol.
Matmosphere send me your address, you'll get it for the price of shipping. Cool?
Cheers!
Quote from: Cortexturizer on August 12, 2016, 02:12:57 PM
I am going for a 1590B, because you know me, I love it when it hurts! Hah!
It really won't fit in a 1590B -- if I could have made it happen I would have. The board is about 3mm too wide to even get in on an angle. 125B is fine though, either horizontal or vertical. (I preferred vertical.)
Quote from: Cortexturizer on August 12, 2016, 02:12:57 PM
Tell you what, I'll PIF the other 2 tapflos. Feck it, your help gents is much appreciated and I often need it, so it all levels out lol.
I'd love to get a chip from you. I'm working on a liquid mercury and twin peaks, slowly. I plan on flashing the chips myself, but I won't know if that works until I have a correct board, but I can't test the board without a working chip.
Dude, that's an amazing offer! Thanks so much. I'll make sure to put it to good use!
Hey guys, apologies for not answering sooner, I was away visiting relatives.
Matmosphere - I will send this to you tomorrow! Will let you know once it's done via PM.
dbp512 - sorry for this but good old Brejan approached me on Facebook so I am giving him the other one. Sorry bro!
The faceplate has been done for this build, I am collecting it in an hour, then drilling, then setting everything up, I should have the build report by tomorrow morning. Excited to add this to my board, it's a great pedal. Thanks everyone for helping me endure through this, it feels good to have completed a pedal finally, I haven't built anything in months.