building the uglyface pcb

[chubfresh]

Howdy.
so i'm running into an issue building this uglyface pcb.
i populated the board, everything looks fine, caps heading the right way, pots wired correctly, vactrol oriented correctly..
but i am getting a super low output, no controls with the pots, and suddenly the volume comes up a tiny bit, and the icm7555 gets super HOT!

i'm kinda pounding my head on the desk with this one.

anyone have any ideas?

thanks y'all!

chuck

[Cozybuilder]

Post photos and a schematic and someone here will be able to help.

[M.A.P]

Hi Chuck,

looks sounds like there's a short circuit on your PCB. Maybe the output of the ICM7555 is shorted. Do you have DMM to measure your PCB?

Pictures of the front and the back of your PCB and a link to the used schematic would help to figure out what's wrong.

Greetings from Germany
Marcus

[chubfresh]

ok..

thank you !

here's a link to the pcb and schematic: http://www.musicpcb.com/pcbs/acln72o2xgsnj8pfqkokmpx0ts5g1g

pinout readings
ICM7555:
pin1 .04
pin2 0
pin3 .5
pin4 3.34
pin5 10.5
pin6 .2
pin7.49
pin8 5.22
JRC386
pin1 1.32
pin2 .04
pin3 .04
pin4 .04
pin5 1.32
pin6 4.95
pin7 10.07
pin8 4.43

there's a noticeable pop when the volume increases and the spike in temp of the ICM7555, which happens about 60 seconds after engaging the effect.
i can't figure out how to post pics...

[M.A.P]

Lets do some more troubleshooting. You said you checked the direction of caps, pots and the vactrol. Did you check the direction of the ICs? Are they on sockets so you can remove them? If so you could remove the LM386 so the ICM7555 doesn't get an audio signal to operate with. Look if it still heats up or what happens after 60 seconds.
I would also check again the wiring of the volume and frequency pots. They're logarithmic and I always wire them up wrong   Notice that in the building PDF is mentioned that the pots are shown from behind.

So that's what I would try next. Hope you get it working

P.S.: I didn't post pictures yet so I can't help you with that problem

[Cozybuilder]

How to post photos is a frequent question.

First, you need to place the photo on a web hosting service- such as Imgur or PhotoBucket. With that, the photo will get a web address. You need to copy that web address, and place it between the brackets that show up after clicking on the photo icon, the (binoculars?) found in the "post reply" toolbar on the far left, just above the smiley face.

If your image address has https, remove the s.

To scale the photo, on the left [img], enter something like "width=500", like this: [img width=500]image address[img]

Finally, hit preview and check what you wrote and if the photo is a good size- extra points for spelling correctly.

[chubfresh]

ok.. haha..

the photo thing i am going to try in a moment.

i switched out the ICM755 for another one, (just for s&g's), and it WORKS!

must be a bad ic i guess..

thank you all so much for your help!

chuck