xox diagnostic help

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shawn rudiman
 
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Joined: Tue Aug 13, 2013 8:28 pm

xox diagnostic help

Post by shawn rudiman »

hi all.

i recently bought a bashed up xox box.. the case was broken, but no damage to either of the boards was apparent. the previous owner had bricked the os trying to upgrade it... so i immeditely replaced the os with a sokkos 1.9.1 pre burned os and seated it correctly. heres my issues: the machine functions well in all modes but theres no sound other than a small snap/pop that corresponds with the gate on. the knobs other than main volume have no effect. tune, cutoff, res, env and decay and accent are allmost impossible to hear when turned. i immeditely guessed perhaps the gate wasnt working correctly (hence not triggering the env, and then in turn the vca. so i plugged in the cv gate to my pro-one and confirmed this: cv functioning correctly. gate not triggering at all. BUT staying high enough to keep the pro-one's gate light on all the time. maybe the gate isnt being pulled back down to zero then? what im hoping is if anyone may have had simular issues and may have a sense of what may be the issue/issues. i can start scoping and probing from the gate pin on the cpu back... but was hoping to maybe save some probing. thanks for the help!

cheers!

shawn rudiman

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altitude
 
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Joined: Wed May 11, 2005 5:17 pm

Re: xox diagnostic help

Post by altitude »

start by checking the VCO, probe the waveform switch pins with some head phones. Work your way back from there. You can easily check the gate by probing the two 4148 diodes at the top of the VCA section in keyboard mode, when you press a key, the voltage should go to 12V

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shawn rudiman
 
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Joined: Tue Aug 13, 2013 8:28 pm

Re: xox diagnostic help

Post by shawn rudiman »

altitude> thanks! i will definetely try those points during the next session im working on her. thanks for the help!

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