[sdiy] problematic sh101

[Roy J. Tellason]

On Saturday 06 November 2004 06:02 pm, Scott Gravenhorst wrote:
> You might want to check power with an Oscope at various points while
> flexing whatever causes it to fail.  If you can make it fail and it's power
> related, that should be quite apparent.  A meter might work too, but if you
> have an Oscope, I think that's a better tool for this purpose.  Set it to
> DC, horizontal sweep freerun.

Agreed!

You will see stuff on a scope that a meter won't even notice...


> "Rude 66" <r.lekx at chello.nl> wrote:
> >well, no luck so far. i think i can say with a bit of certainty that it
> >isn't the power supply board, because this seems to be the only thing
> > that's wedged in firmly. i resoldered the various connections there, and
> > a visual inspection didn't show anything.
> >i took the whole synth apart and inspected all the boards by eye and
> >maginfying glass, resoldering various bits (all right, john,
> >'reflowing'..;-) especially those involved with the power distribution and
> >on/off switch. completely removed that sequencer board too. the result? it
> >stays on a bit longer than before.. but touching it in any way, especially
> >the now empty sequencer/arpeggio part, and where the 'vco' and 'env' are
> >written on top of the panel, makes it go on/off. pushing it down a bit on
> >the left botton and right top corners makes it come on again..
> >
> >funny thing is, it didn't have this on/off problem when the seqencer board
> >was in, only when it was laying open. but then, as soon as any of the
> > lights there came on, it would stop playing.. then pushing on the synth
> > would make these lights go on and off randomly. grumpf.
> >
> >diagnosis so far would be that it either is the controller board holding
> > all the knobs and sliders, since that screws right on to the case where
> > you push it. and it only takes a light, gentle touch to make it go
> > on/off. or it's those multicables that connect the 2 boards together,
> > they're white almost like flatcables in a computer and very stiff.
> > problem with the boards is also that there's a layer of shiny goop on top
> > of everything (like flux?) that makes bad traces almost impossible to
> > see.. i'll try dave's
> >led-solution tomorrow, but i don't have time to spend days on this thing..
> >
> >thanks for all the tips so far!
> >
> >r./
> >
> >
> >
> >
> >----- Original Message -----
>
> From: "Scott Gravenhorst" <music.maker at gte.net>
>
> >To: <synth-diy at dropmix.xs4all.nl>
> >Sent: Saturday, November 06, 2004 6:24 PM
> >Subject: Re: [sdiy] problematic sh101
> >
> >> "john mahoney" <jmahoney at gate.net> wrote:
> >> >> there goes another quiet saturday night..;-)
> >> >
> >> >Party on, Rude! ;-)
> >> >
> >> >I have a comment on what you said about "before i start on resoldering
> >> >all connections"...
> >> >
> >> >Maybe this isn't what you meant, but you don't have to actually
> >> >*re*solder them. That is, you don't have to remove the old solder and
> >> >add new solder. All you've got to do is touch them with a hot iron for
> >> >a few seconds to melt the existing solder. "Reflow" is the term, I
> >> >think. This shouldn't take all that long, even for a whole board or
> >> >two. I mean, yeah, there are a lot of connections, but you can move
> >> >pretty quickly from one to the next. Could be easier than trying to
> >> >find that one cracked joint.
> >>
> >> This is what I do as well.  Sometimes seeing a crack in solder, even
> >> with a magnifier, is difficult or impossible, especially if the crack
> >> is tight around a component lead.
> >>
> >> As was mentioned before, I'd start with the power supply and it's
> >> connections to the various boards.
> >>
> >>
> >>
> >>
> >> ---------------------------------------------------------
> >> - Where merit is not rewarded, excellence fades.
> >> - Hydrogen is pointless without solar.
> >> - What good are laws that only lawyers understand?
> >> - The media's credibility should always be questioned.
> >> - The only good terrorist is a dead terrorist.
> >> - Governments do nothing well, save collect taxes.
> >>
> >> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
> >> -- Linux Rex         | RedWebMail by RedStarWare
> >> -- FatMan: home1.gte.net/res0658s/fatman/
> >> -- NonFatMan: home1.gte.net/res0658s/electronics/
> >> -- Autodidactic Master of Arcane and Hidden Knowledge.
>
> ---------------------------------------------------------
> - Where merit is not rewarded, excellence fades.
> - Hydrogen is pointless without solar.
> - What good are laws that only lawyers understand?
> - The media's credibility should always be questioned.
> - The only good terrorist is a dead terrorist.
> - Governments do nothing well, save collect taxes.
>
> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
> -- Linux Rex         | RedWebMail by RedStarWare
> -- FatMan: home1.gte.net/res0658s/fatman/
> -- NonFatMan: home1.gte.net/res0658s/electronics/
> -- Autodidactic Master of Arcane and Hidden Knowledge.