[sdiy] problematic sh101

[Scott Gravenhorst]

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.

"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.