sequencer not working

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Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

sequencer not working

Post by Mussi81 »

hi
just turned on my self sourced x0x first the first time and guess what it doesnt work lol

when i power on i can hear its powered through headphones

usb is working and computer picks it up

none of the leds light up and none of the buttons seem to do anything.

i also cant seem to get a decent voltage @ j4 on the mainboard

when i was building it i did all the checks up untill i had to apply 2v dc as i dont have the means to do this!



your help would be much appreciated

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

and also i havent fitted the two 2.5 sockets for cv and gate as i dont have 2 of them

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

ive just gone over the board and checked the soldering and found this.

i cant lift the solder and break the connection, could this be causinbg an issue?
Attachments
led short.jpg
led short.jpg (108.34 KiB) Viewed 3340 times

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

I've checked al the ic's and they are all giving me around 2.5v ac

I also have a sokkos microcontroller installed

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

what are the voltages on j4
if they are not 5.333v and 12v
remove the jumper to the mainboard
and measure them again
if they come back up
then there is a short on the mainboard

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

Hi guest

I removed the connection to the mainboard at j4. I now get 5.33v and 11.86v at j4 on the I/0 board.

I also have these voltages on the mainboard at j4

I'm not sure what to do next?

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

if the voltages are stable
when you reconnect j4 to the mainboard
then check to see if the vco is working
by listening at the waveform switch

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

Hi guest

I have found that I inserted ic6 round the wrong way! Ive managed to get the ic chip out, breaking one of the legs in the process. No worries I think I can get some more chips easily.

Should of socketed the chips in the first place.

In the process of taking out the chip I have scratched through to the copper on the board very very close to one of the solder pads! So what are my options here? Scratch through the board past the copper trace breaking any possible short?!?

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

is the copper for a trace
or is part of the ground plane

if its the ground plane
then dont worry about it

if its a trace
measure the resistance across the cut
if its actually broken
then just solder it closed again

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

hi (again)

i finally got the correct ic,

just turned on my x0x and when i press the keys in keyboard mode theres no sound just a hum! also not all the leds light up when switching it on

anyone have any ideas where to start? :)

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

check the supply voltages again on j4 and j3
if those all look good
check if the gate out is going high
when you press a note in keyboard mode

do the modes work besides for not making sound

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

guest wrote:check the supply voltages again on j4 and j3
if those all look good
check if the gate out is going high
when you press a note in keyboard mode

do the modes work besides for not making sound
when i turn the unit on and press keys as soon as it finished intializing i can here both waveforms but its as if the volume fades away very quickly.

it appears that the mode selector is working ok. will check those voltages now

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

so its as if it works fine
for a short bit of time after start up
but then the sound fades out and doesnt come back

sounds like something in the envelope generator

guest
 
Posts: 3155
Joined: Fri Feb 17, 2006 5:35 am

Re: sequencer not working

Post by guest »

check q32 q38 and d36
for proper type and orientation

Mussi81
 
Posts: 98
Joined: Tue Dec 01, 2009 3:22 pm

Re: sequencer not working

Post by Mussi81 »

guest wrote:so its as if it works fine
for a short bit of time after start up
but then the sound fades out and doesnt come back
yeah its very brief and quiet though

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