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Power switch flickering - problem/question

Power switch flickering - problem/question

2009-02-27 by mattvrazo

I thought I better start a new post instead of 'jack the DAC thread.

I noticed recently that depending on the angle of my xpander i.e.
flat, versus angled on a rack where it normally sits, there is
flickering in the power switch light.  There is more flickering the
more horizintal it is, and none at all when it is vertical. 

I don't know if it's coincidence that it seemed the only trouble I
ever had with tuning (the filters, not the voices), was when it was
flat.  All the filters passed, but the they were never completely when
self-oscillating (they are when it's more vertical).  They kept being
out of tune on two voices in particular, so I thought it might have
been a filter chip issue, but then I put it back on the rack and had
no problem.

More than anything, I am worried the flickering is indication that
something is somehow "moving" around...  something power supply related:/

I plan to have the whole thing pre-emptively serviced (recapped) soon
anyways, but does anyone have any clue what the flicker might be a
sign or, or the result of?

Re: Power switch flickering - problem/question

2009-02-27 by envia94

I have had a similar flickering light on my fridge for year. I think it is not serious in case of an 
Xpander either. That's probably a property of the bulb itself due to some manufacturing 
tolerances. Although stable LEDs were invented, they were not used in Xpanders, if I'm not 
wrong:

http://web.mit.edu/invent/n-pressreleases/n-press-04LMP.html

Re: Power switch flickering - problem/question

2009-02-27 by mattvrazo

--- In xpantastic@yahoogroups.com, "envia94" <akva@...> wrote:
>
> I have had a similar flickering light on my fridge for year. I think
it is not serious in case of an 
> Xpander either. That's probably a property of the bulb itself due to
some manufacturing 
> tolerances. Although stable LEDs were invented, they were not used
in Xpanders, if I'm not 
> wrong:
> 
> http://web.mit.edu/invent/n-pressreleases/n-press-04LMP.html
>

Ok, that's good to know...  it's just odd that it seemed correlated
with how well the filters tuned.. It had me hesitating about even
turning it on, but maybe that's been overcautious.

Re: Power switch flickering - problem/question

2009-02-28 by Karl

Hi Matt,
I would agree with Envia. The flickering of the neon bulb in the power 
switch has naught to do with any other hardware problems. The bulb is 
connected to the line voltage right at the switch and is isolated from 
the rest of the circuitry by the power supply transformer.

However, if when you physically position the xpander differently and 
you have tuning problems, this points to something  loose in the 
circuitry. You might try opening it up and pushing all the chips down, 
and/or any connectors feeding to the voice boards. Statistically, 
tuning problems usually point to failed caps or cold solder joints.  

Also, Envia's cautions about static electricity is very good advice. 
The humidity is so high here in St. Louis I don't 
usually have problems with this.  

- Karl


--- In xpantastic@yahoogroups.com, "mattvrazo" <vrazomatt@...> wrote:
Show quoted textHide quoted text
>
> --- In xpantastic@yahoogroups.com, "envia94" <akva@> wrote:
> >
> > I have had a similar flickering light on my fridge for year. I think
> it is not serious in case of an 
> > Xpander either. That's probably a property of the bulb itself due to
> some manufacturing 
> > tolerances. Although stable LEDs were invented, they were not used
> in Xpanders, if I'm not 
> > wrong:
> > 
> > http://web.mit.edu/invent/n-pressreleases/n-press-04LMP.html
> >
> 
> Ok, that's good to know...  it's just odd that it seemed correlated
> with how well the filters tuned.. It had me hesitating about even
> turning it on, but maybe that's been overcautious.
>

Re: [xpantastic] Power switch flickering - problem/question

2009-03-06 by Simon G

funny you should mention the vertical vs. horizontal placement of the synth...watched a video interview of the guy from goldfrapp (it's quite good i thought http://tv.sonicstate.com/play.php?vid=155) and he says old synths store better on their sides. he doesn't seem to know why but i'd imagine he's dealt with a lot of synth repair and synth repair folks over the years.

Show quoted textHide quoted text

--- On Fri, 2/27/09, mattvrazo wrote:

From: mattvrazo
Subject: [xpantastic] Power switch flickering - problem/question
To: xpantastic@yahoogroups.com
Date: Friday, February 27, 2009, 2:13 AM

I thought I better start a new post instead of 'jack the DAC thread.

I noticed recently that depending on the angle of my xpander i.e.
flat, versus angled on a rack where it normally sits, there is
flickering in the power switch light. There is more flickering the
more horizintal it is, and none at all when it is vertical.

I don't know if it's coincidence that it seemed the only trouble I
ever had with tuning (the filters, not the voices), was when it was
flat. All the filters passed, but the they were never completely when
self-oscillating (they are when it's more vertical). They kept being
out of tune on two voices in particular, so I thought it might have
been a filter chip issue, but then I put it back on the rack and had
no problem.

More than anything, I am worried the flickering is indication that
something is somehow "moving" around... something power supply related:/

I plan to have the whole thing pre-emptively serviced (recapped) soon
anyways, but does anyone have any clue what the flicker might be a
sign or, or the result of?


Re: Power switch flickering - problem/question

2009-03-07 by mattvrazo

huh, interesting vid.  Though he seems to be saying the reverse-i.e. don't keep them on their side! (and maybe the chroma in particular).  I guess it depends on whether there are individual voice cards that could bend against their sockets.  
My Xpander is always "horizontal", just at varying degrees depending on whether it's on a stand, or sitting flat.  

--- In xpantastic@yahoogroups.com, Simon G <playthefivetones@
...> wrote:
Show quoted textHide quoted text
>
> funny you should mention the vertical vs. horizontal placement of the synth...watched a video interview of the guy from goldfrapp (it's quite good i thought http://tv.sonicstate.com/play.php?vid=155) and he says old synths store better on their sides. he doesn't seem to know why but i'd imagine he's dealt with a lot of synth repair and synth repair folks over the years. 
> 
> 
> --- On Fri, 2/27/09, mattvrazo <vrazomatt@...> wrote:
> 
> From: mattvrazo <vrazomatt@...>
> Subject: [xpantastic] Power switch flickering - problem/question
> To: xpantastic@yahoogroups.com
> Date: Friday, February 27, 2009, 2:13 AM
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>     
>             I thought I better start a new post instead of 'jack the DAC thread.
> 
> 
> 
> I noticed recently that depending on the angle of my xpander i.e.
> 
> flat, versus angled on a rack where it normally sits, there is
> 
> flickering in the power switch light.  There is more flickering the
> 
> more horizintal it is, and none at all when it is vertical. 
> 
> 
> 
> I don't know if it's coincidence that it seemed the only trouble I
> 
> ever had with tuning (the filters, not the voices), was when it was
> 
> flat.  All the filters passed, but the they were never completely when
> 
> self-oscillating (they are when it's more vertical).  They kept being
> 
> out of tune on two voices in particular, so I thought it might have
> 
> been a filter chip issue, but then I put it back on the rack and had
> 
> no problem.
> 
> 
> 
> More than anything, I am worried the flickering is indication that
> 
> something is somehow "moving" around...  something power supply related:/
> 
> 
> 
> I plan to have the whole thing pre-emptively serviced (recapped) soon
> 
> anyways, but does anyone have any clue what the flicker might be a
> 
> sign or, or the result of?
>

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