Sv: Re: [sdiy] tr909 schematics -> sequencer part

[Daniel Araya]

>>> "Rude 66" <rude66 at xs4all.nl> 2005-03-14 15:50:11 >>>
>
>well, resoldering the circuit board didn't do much here. the problem
seems
>to be related to the patterns. all bank/pattern select functions work,
sync,
>tempo etc work, but as soon as you play a pattern, it's impossible to
>program it: lights come on/off randomly, and the patterns are one big
mess.
>also steps you turn on or off are something else in the next run
through,
>and a lot of sounds seem to be double triggered (or it's stuck in
flam
>mode). other weird thing: is start/stops in pattern mode, but not in
song
>mode..
>
>after some consultation with Senso, tonignt i'll fire it up with bare
boards
>and power on to see if there's any spots where i can detect trouble.
>suspicious spot is the bottom right pasrt of the seq board, because
there a
>little clip was also knocked off the plastic side panel of the case.
it
>seems to have taken a beating.
>
>what's the best way to measure and fix a broken trace on something
like
>this?? i have a dmm, but no scope..

It sounds like something might be wrong with the RAM-adressing or
data.
The best way may be to visually look with some sort of magnifying
glass, I found the fault using a small magnifyingglass that
stamp-collectors use (I don't know the word in english!) and look
carefully at each trace. If you find anything suspicious measure the
conductivity with the DMM.
Then get a scope! :) If you lived closer to Sweden I would give you
one, I got two Phillips scopes for free and already have a good Tek!

/d