Power Supply Construction Issue

by **omnesilere** » Mon Mar 07, 2011 1:40 am

the capacitors are supposed to build up and then hold a steady charge? or are they supposed to keep going up and down in voltage? im confused by c3 and c5 i think.

by **guest** » Mon Mar 07, 2011 1:46 am

give this a try

take a look at the second picture on this page
http://ladyada.net/make/x0xb0x/fab/ioboard/index.html
at the bottom of the pcb
you will see a very thick trace
running the whole length of the pcb

you can also see a short bit that comes up
and goes to the usb section
first connecting c203

if you take a banned blade
and cut this trace as right before c203
so the long trace on the bottom is still good
but the short trace to the usb section is broken
you will remove the 5v supply from the usb

if you want in the future
you can resolder the break

by **omnesilere** » Mon Mar 07, 2011 1:57 am

would it be possible to take out c203? i tried cutting it but i think its still contacting. i dont want to gouge the board too badly. brilliant solution though! thank you!

by **omnesilere** » Mon Mar 07, 2011 2:04 am

that wouldnt work would it? removing c203.

i scratched it enough. just had to do some more back n forth...

now for the testing...

by **guest** » Mon Mar 07, 2011 2:04 am

taking out c203 wont help

usually when i break a trace
i cut two lines across it
spaced about 3mm apart
and then i dig out the copper inbetween

with the power off
you can measure the resistance across the break
and see if it is still connected

once its broken
measure the voltages on ic20 again
and see if they have popped back up to 5v

by **omnesilere** » Mon Mar 07, 2011 2:19 am

power off checked the resistance (200k ohms) from ic20 and c203 and it comes up with 10.8... somehow they're still connected? i gouged out where you said, its definitely not from there. gouged just above the main along the bottom (coming from ic20) that goes into c203.

by **guest** » Mon Mar 07, 2011 2:38 am

thats fine
as long as its not 0ohms

check the 5v power

by **omnesilere** » Mon Mar 07, 2011 2:45 am

(DC 20 meter)
IC20 in: 14.4V
IC20 middle: 0.0 V
IC20 out: 4.95 V
across in and out: 9.55V

(AC 200 meter)
IC20 in: 30 V
IC20 middle: 0.0 V
IC20 out: 10V
across in and out: 20 V

Also more sparking. i accidentally touched the IC20 in and the IC20 middle pin : (

by **guest** » Mon Mar 07, 2011 2:48 am

now reconnect the mainboard to the ioboard
it should work now

by **omnesilere** » Mon Mar 07, 2011 2:49 am

Really!?! Holy awesomeness! Alright just a minute let me test this out... getting headphones...

by **omnesilere** » Mon Mar 07, 2011 3:02 am

IT WORKS!!!

THANK YOU!!! Oh because of you another x0xb0x has been born from its fetal stage right into teen angst!! : D

I wish I could offer you something! you stuck with me all through this tonight. Four months of worry and strife gone and now a 303 clone is in my hands and ears

Congratulations on your engineering / problem-solving skills. I feel blessed (though honestly i'm not religious) Thank you! Thank you again!

by **guest** » Mon Mar 07, 2011 3:07 am

im glad to hear its working

if you get bored sometime in the future
you can tackle replacing that usb chip
although its only really good for uploading new firmware
and you cant do that with a tt box anyways
youd need to get a new microcontroller

by **omnesilere** » Mon Mar 07, 2011 3:15 am

i just got a little modular. with 303 and evila, you can look it up on ebay I now am analog : ) and i can use the cv and gate on this and midi... so i effectively have a xoxboxmodular synth. ive got to go test that out...like tonight

not worried about the usb at all! which is nice that I can be, since the firmware is already on it. i was worried about having to program it.

one quick mod and i can put it together. going to do the bass boost: change C21 and C20 from .01uF to .1uF

im so glad that was the issue. i was so diligent. checked everything three times before putting it in... had friends check my soldering... it stopped me for a while because the power wasn't right but i had to build the rest to know for sure. im glad there isn't any damage (beside that done to fix it haha!)

really i hope i can pass on the favor to someone. thank you again.

im glad to hear its working

if you get bored sometime in the future
you can tackle replacing that usb chip
although its only really good for uploading new firmware
and you cant do that with a tt box anyways
youd need to get a new microcontroller

by **omnesilere** » Mon Mar 07, 2011 4:36 am

I did two quick mods:
Bass Boost and the Full Env mod: replace R61 with a jumper.
This sounds great!

Too bad I got a faulty usb chip or whatever that was! ugh! I'm gonna have a word with chipforbrains.

now to learn how to save this cool pattern i just made :wink:

Power Supply Construction Issue

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