Building the tap tempo tremolo

[good air]

Thanks man, just got home so I'll get started and let you know how it turns out.

[good air]

Maybe a dumb question but whats are those pads that are in the traces on the board with no parts assigned to them?  There's one next to the diode and one next to the cap on the left of the taplfo.  Are they supposed to be filled with solder?

[.Mike]

They make connections from the top side of the board to the bottom. You don't have to do anything to them.

Mike

[good air]

gracias friend

[good air]

Well ran into some problems with this last night, hoped to get it situated this afternoon but no luck.  Got bypass, got led, reflowed joints, did some probing and getting tones up to the photocoupler but i'm not sure exactly where the tones stop (not too good at following schematics).  No trem though and the show is in a few hours.  Any ideas?

[Taylor]

Is your LED flashing?

Do you have the opto in right? The long leads are the resistor side, the short leads are the LED side. The white dot on the opto is the negative LED lead, put the other side (the one without the dot) where the + sign is on the board.

[good air]

Thanks for the fast reply.  No led flashing.  The white dot is opposite the + sign on the same side, the long leads are in the pads next to the trim pot.  I'm uploading some pics now.

[good air]

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http://img194.imageshack.us/img194/3431/boardfrontj.jpg



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[candidate]

What gauge wire are you using?

[good air]

22

[Taylor]

Check that you have 5v at pin 1 of the taplfo. See if you have any voltage on the pos leads of the LEDs, and what that voltage is if so. Check if the rightmost pin of the 3904 is connected to ground (probe the lead itself, not the pad).

It's tough to see whether you have solder bridges or just glare on the flux on your board, but it does appear that you have some long unclipped wires sticking out of the solder joints. It may not be the problem here, but it's good practice and will save yo headaches to clip everything right up to the joint.

[good air]

Thanks for the tip on the long leads.  Once its done, I'm going to clip everything and clean it up and put some cardboard on the bottom.  I have a blue led to put in there too and the box isnt painted yet, just trying to use it tonight.  Hopefully!

Anyway..

Got exactly 5 volts on pin 5 of taplfo and the led, opto has 4.9 on the postive.

Right most pin on the 3904 gave me the beep on the lead and the pad.

[KazooMan]

What is the purple lead that snakes around the LED pins and appears to terminate near the opto?

[good air]

Thats goes from the middle pin of the 3pdt to the 10k resistor to wire the led.  Taylor posted the diagram a few posts up.

[KazooMan]

Got it, I missed Tyler's post.  It does look like you tried to tie into the thin trace to the 10K resistor rather than hitting the same hole in the pcb or tying into the leg of the resistor.  Are you certain you haven't shorted out any connections here?

I also had some major league ticking problems and found that they were very dependant on the lead dress of the LED.  I finally went for the nuclear option and installed a separate "effect on" LED and moved the tempo LED wiring away from the stomp switch.  I also rewired the input and output lines and LED with shielded cable.  I cannot tell you which of these changes worked the magic, but the pedal is dead silent in operation and in bypass.

[good air]

Yeah i soldered it to the leg of the resistor.  It lights up so thats good, no blinking though.  I don't know anything about this particular wiring and shorts but first thing I did to debug was check for bridges/shorts and cold joints.  Unfortunately it doesn't look like this is getting fixed tonight cause I gotta get everything together.  Next month's show = massive trem.  I'll be back tomorrow afternoon and hopefully you guys can help me get this going.  Thanks!

[Taylor]

I don't know how much you fiddled with the pots, but if you have it set on square wave with the wave distort all the way to left I think, it will be always on. Also, if you have the depth all the way down the LED will stay lit all the time. Do you have sound coming though when the effect is on and the LED is lit up but not flashing?

[good air]

Alright I'm back.  Hungover but back.   I was messing with the pots a little and it didnt change the led, still doesnt blink, the trimpot adjusts the brightness but its just on.  I have no sound coming out when the effect is on, I made an audio probe and poked around and get sound up until the opto but its not a tremolo sound anywhere.  Any ideas on what parts to check out? 

[Taylor]

Hmm, it's weird, because if the TAPLFO was not functioning it would not put out a signal, so the LED shouldn't light. So the chip must be functioning but maybe you have a short in the wiring of the depth knob that causes it to be minimum depth.

Did you try tweaking the trim right next to the TAPLFO while probing the resistor side of the opto coupler? If the visible LED is lit, then the opto should light as well, which would give you audio unless the trim is too far in one direction.

[good air]

Alright its getting there.  Adjusted the trimpots and depth like you said and it blinks now.  I also moved that purple wire away from the led.  The Depth knob was the culprit because it had to be maxed out for blinking.  Tap and multiplier switches work but its not really tremolo-ing.  If I put the Depth all the way up and Wave Distort all the way down, I get trem but its more of a clean signal, not very deep.  some settings on the Wave shaping knob are better at tremolo than the others.  Going to mess around with the settings a little more.