UglyFace Troubles

[gluedtogether]

I built an ugly face based off of the home-wrecker site. John lyons (basicaudio) created the layout for me. I have attached the layout below.

I have gone through the layout and verified my parts are correct and the layout matches. I didn't notice any solder bridges. I used a layout from John Lyons based on the homewrecker layout.

When I play, I have to carefully tune the frequency and threshold to hear the guitar come through but will die out after 15 seconds and I have to readjust the knobs. Otherwise it acts like an atari punk console. The sensitivity knob does not seem to do anything.

I have been checking the forum for troubleshooting posts and found a lot of mention around chips
http://www.diystompboxes.com/smfforum/index.php?topic=49569.0
I have a LM386N-1 from radio shack and a TS555CN (which I believe is CMOS) .

If anyone has any suggestions on what to try, let me know. I will try and measure voltages. If anyone has the correct voltages, let me know. Thanks in advance

[gluedtogether]

-bump-

hoping someone has some insight...

[GREEN FUZ]

Just a suggestion. Check your wiring carefully. Speaking from experience, it`s easy to get your input/output jack wires confused. Your problem sounds a little like the one I had when I got the ground and input wires mixed up.

As always, good luck.

[gluedtogether]

Thanks for the suggestion. I will check that out. if it doesn't seem to work, I will try and post the wiring layout I did off the board.

[gluedtogether]

Took me a while to get to this, but I added my wiring to John's layout. Hopefully someone will spot something...

any suggestions are welcome, thanks

[GREEN FUZ]

Your offboard wiring 'seems' to be alright, as far as I can tell. The only aspect I`d find noteworthy is the ground wire between the input and output jacks. I only say this because it`s not the way I do it. I`d have the ground going from the output jack straight to the board. I couldn`t say whether or not this would account for the symptoms you`ve described. Probably not.

[Boogdish]

make sure you've got the pots wired correctly as well, I get my lugs backwards every now and then.  You should also check with a meter to make sure the pots work, I spent a few hours banging my head against a wall (figuratively) trying to get a trem to work a couple weeks ago and it turned out that I had a non functioning pot.  Rare, but it happens.

[Mick Bailey]

LM386N-1 works fine in the Uglyface.

[gluedtogether]

I checked the layout and I am pretty sure I have the pots wired correctly, but will check again. I have missed things before

Thanks for the comment on the chip. the 555 i have in there now is a ts555CN

Does anyone have the voltages for the chips?

Thanks

[oldrocker]

I know this may sound silly but are capacitor polarities oriented correct? 

[gluedtogether]

never a bad suggestions, I had the problem with a tantulum cap I didn't realize was polarized

The Caps match the layout above, so if those are correct, I should be fine. thanks for the suggestion

[John Lyons]

The "bad pot" possibility may have some merit. Seems that there have been a lot of cases of that.
Sometimes the pot lugs aren't solidly connected to the wafer with the resistive strip.
If you have the post try replacing the freq and theshold pots. Or de solder them and test them to make sure that they read resistance throughout the pots travel etc.

John

[Mick Bailey]

The sensitivity pot should make quite a bit of difference and it would suggest that your LED/LDR combo is not working properly. You could temporarily hook up an LED across the outer lugs of the pot and look at the brightness - it should be pretty bright when you hit a note. Even when this control is turned right down you should get a loud signal out, though.

Obvious - but are the ICs oriented correctly? I've just built an LFO for my own UglyFace and put the op amp in the wrong way in my haste to get it from breadboard to PCB. If they are, check for 9v operating voltage on your ICs with reference to their ground pins.

Check that your LDR is not shorted out.

When I have problems with a circuit I always check it under bright light with a magnifying glass - sometimes a joint looks ok but on closer inspection can sometimes not have bonded to a component leg. This can happen on bandolier components if the adhesive sticks to the leg, or if the component is a little oxidised.

Just another thought - have you installed the wire links - especially the one under the 7555?

[oldrocker]

I had a bad Vactrol when I first built mine and it took me hooking in a home made LED/LDR combo to get mine going.  It's worth a shot.

[gluedtogether]

Thanks for all the suggestions. I will check the posts and pop in a home made LED/lDR combo I have in another pedal
The ICs are correct and I have gone through the board with a magnifying glass and everything looked good. I will try the suggestions and see what I get.

thanks

[gluedtogether]

The vactrol was socketed so I took that out and put a LED in place to see if it lit, it didn't. This must be the source of my problem. everything seems to match the layout from john. I am cross referencing it from the homewreck site too

I replaced the 2.2 cap that feeds into the sens pot and also replaced the sens pot to see if they were defective. no change. still not getting the led to light

[gluedtogether]

I got my new order of pots and replaced the pots no real change. Plugged in a couple of new 555s and that seems to works, but intermittantly - I can keep trying more, I bought 5cmos

I still can't get the LED to light. I put an LED in to test if it lights, no luck

I am not sure where the POS voltage comes in to light the LED, If I am reading correctly,  the pos signal comes from the 386 through 2.2uf, then up to the sens pot lug 3 to lug 2 then down to the LED. I am not getting a pos signal after the 2.2uf...am I missing anything

[Mick Bailey]

As a check, unplug both ICs and put your socketed LED back in, Now connect a temporary wire with a 1k resistor in series (to limit the current) from +9v side of the 1N4001 to the left-hand side of your SEN pot (as referenced from your diagram). The LED should now light and the pot should act to dim the LED completely when turned down.

If the LED doesn't light, either the LED is not correctly grounded, it's reverse-connected, or you have a wiring error.

If it lights, and the pot operates on the brightness, then the problem is clearly further back. You should then try the pedal with just the 386 installed (remember to remove temporary wire, above) to see if the LED lights with the SEN pot maxed and with a guitar signal.  Leave the 555 out until you've got the 1st stage operating the LED.

Check again;

1. The polarity of the caps.

2. That the jumpers are installed correctly.

3. That there is no possibility of a short pulling the voltage down on pin 5 of the 386. To further isolate the 386, remove the jumper connecting the two 2.2uf caps together and test again with a guitar signal.

[gluedtogether]

Add the wire in, I got the LED to light. The SENS pot controls the dim. When the 386 is in, it doesn't work. I am only getting 1.4volts out of pin 5 and that doesn't match this thread. I think this may be the problem. All the other voltages match. i tried the other suggestions.
http://www.diystompboxes.com/smfforum/index.php?topic=42826.0

I checked the polarity of the caps as well...

Thanks for the suggestions, I will keep probing

[Mick Bailey]

Just taking another look at the schematic and wonder if you've got a wrong value resistor. I'm suspecting maybe the 1M on the input might be too low. Worth double checking.

One characteristic of this design is the deafening volume out of it. Unity gain should be with the volume not much off the mark. At 9 o'clock it should be well OTT.

Does your's do this?