finished assembling, encountered problems

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pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

finished assembling, encountered problems

Post by pharmatic »

hello everybody,
my mm x0x is now finished and passed all the tests along the way, but after switching it on, ive encountered some major issues:

1) there is no sound to be heard on either the main out and the headphone out
2) led 13 is about half as bright as the others, led 16 is not working at all (i suspect them to be faulty and will replace them, but who knows)
3) when switching it on, different leds illuminate all the time, sometimes all of them (exept 16, see above), sometimes none.
4) the tempo trimpot (s2) does not seem to affect the tempo, it always blinks the same speed witch is very slow.
5) the internal clock seems to be all messed up, when i run a pattern, the steps are kind of shuffeled. i.e there are different gaps between them. some of the leds sometimes dont illuminate, but that behaviour seems to be random.

obviously, i made quite a lot of mistakes down the road and would be more than gratefull if some of the more experienced x0xers could help me fixing those issues.

ps: i soldered the xtl1 in the i/o board but found the mistake before applying power. i desoldered it, witch was not too easy, and since this part is quite sensitive to heat i supect it to be damaged

also, the 5v rail seems to be ok, i measure 5v on pins 9 and 40 of the microcontroller and ic20 does not get any hot.

so, any hints are greatly appreciated - many thanks in advance!

cheers!
Last edited by pharmatic on Mon Feb 13, 2012 1:03 pm, edited 1 time in total.

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

i also checked for any possible shorts on the pcb's but could not find any.

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altitude
 
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Re: finished assembling, encountered problems

Post by altitude »

what are your voltages at J4?

pharmatic
 
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Re: finished assembling, encountered problems

Post by pharmatic »

5,33v on pin1, 11,85 on pin 3

guest
 
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Re: finished assembling, encountered problems

Post by guest »

do any of the modes work
do leds light up like they should in keyboard mode

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

when in keyboard mode, the leds light up when i push the corresponding button. pattern edit also seems to work

guest
 
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Re: finished assembling, encountered problems

Post by guest »

measure the voltage at gate out
when press a key in keyboard mode
and see if it goes from 0v to 12v and back again

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

its about 0,5v when no button is pressed and about 11,9v when pressed.

guest
 
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Re: finished assembling, encountered problems

Post by guest »

is there sound at the waveform switch
when you probe with a pair of headphones

how about at the resonance pot
or volume pot

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

i do get what seems to be asawtooth at the waveform switch, but the sound isnt affected by its position. then i have just some crackles at the resonance and nothing at the volume. :?

guest
 
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Re: finished assembling, encountered problems

Post by guest »

do you hear the frequency of the sawtooth change
as you play notes in keyboard mode

sounds like a problem with the vcf
you should check your voltages in that area
with the voltage map given in the forums

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

yes, the frequency changed, although i had the machine in random mode. will check the voltages.
by the way, thanks for your efforts so far! you are very helpful :D

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

alright, i measured the voltage of all the parts in the vcf section and compared them with the values of the voltage map.
quite A LOT of VERY WRONG values. :oops:
will try to figure it out tomorrow, nevertheless i attached the list in case somebody cares to help me out :wink:

http://www.2shared.com/document/zgY12Zu9/VCF_Volts.html

have a good night!

guest
 
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Re: finished assembling, encountered problems

Post by guest »

q22 is bad
someone had a bad mm q22 last week as well

pharmatic
 
Posts: 19
Joined: Wed Feb 08, 2012 5:58 am

Re: finished assembling, encountered problems

Post by pharmatic »

i already thought so after having a look on the schematic, but thank you very much for confirming.
kudos to you, sir!

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