Discussion about the Korg PolySix synthesizer

Hi folks!

My Polysix after battery leakage had the typical symtomps you might 
expect. 

After having cleaned & resoldered the guts everything's fine apart from 
the memory; 
I create a patch, I press WRITE, I choose the location. Seems OK. But 
just click another patch, then come back to the one I just saved - and 
it's not there. A new 3.6V battery has been installed, but it is not 
the matter of battery, beacause we are talking about doing this when 
the synth is still operatnig, being plugged, so it has all the power 
needed all the time.

I'm inclined to think the TC5514 S-RAM chip is the culprit, because all 
the chips keep voltage of 5V whereas this one has just 4V.

What do you think ? What replacement part for TC5514 should I look for?
I've heard about Intersil HM6514 and Nec uPD444c (D444C-6514) but are 
these really the only ones? I came across some chips with 'similar' 
characteristics and I really would like to avoid importing the above 
mentioned ICs.

I'm not a tech, but a tech's opinion would be greatly appreciated and 
helpful.

  cheers
  aero

hi,
I don't think your RAM is damaged, try to find broken traces on the PCB
leading to it. If some of them are damaged by battery leakage, writing a
patch will actually write random stuff to the RAM, same thing when trying to
read a patch. It's OK for RAM to work at smaller voltage, because it's
powered via diode. Although I'd expect something like 4.5V and not 4.
It's hard to find replacement chip. I made a small adaptor, that takes
typical RAM and converts to TC5514 pinout, pictures included.
BTW, desoldering RAM can add more damage to the board if you're not
carefull. OTOH it can fix some problems if there was some intermitent
contact at some of the RAM leads.

Roman

----- Original Message -----
From: "sputnik979" <sputnik979@yahoo.com>
To: <PolySix@yahoogroups.com>
Sent: Tuesday, June 27, 2006 8:43 PM
Subject: [PolySix] Memory failure, S-RAM suspected.


> Hi folks!
>
> My Polysix after battery leakage had the typical symtomps you might
> expect.
>
> After having cleaned & resoldered the guts everything's fine apart from
> the memory;
> I create a patch, I press WRITE, I choose the location. Seems OK. But
> just click another patch, then come back to the one I just saved - and
> it's not there. A new 3.6V battery has been installed, but it is not
> the matter of battery, beacause we are talking about doing this when
> the synth is still operatnig, being plugged, so it has all the power
> needed all the time.
>
> I'm inclined to think the TC5514 S-RAM chip is the culprit, because all
> the chips keep voltage of 5V whereas this one has just 4V.
>
> What do you think ? What replacement part for TC5514 should I look for?
> I've heard about Intersil HM6514 and Nec uPD444c (D444C-6514) but are
> these really the only ones? I came across some chips with 'similar'
> characteristics and I really would like to avoid importing the above
> mentioned ICs.
>
> I'm not a tech, but a tech's opinion would be greatly appreciated and
> helpful.
>
>   cheers
>   aero
>
>
>
>
>
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>
>
>
>


[Non-text portions of this message have been removed]

Hi !
The case is that it is my tech who's doing all the dirty work ;) I'm 
just managing & providing insights, let's call it. He has schematics 
and he knows what he's doing; he replaced the bad SN chips and 
resoldered all the bad traces so that now all formerly dead functions 
like octave switching, subosc, ADSR, cutoff, attenuator work fine. 
Now he's sort of asking me what to do, because all the traces seem 
fine, and this one IC is diffferent from others in the way of keeping 
4V. So we have a complementary cooperation here as you see ;)
And the question of random patches/values:
If I create let's say a deep bass patch and save it to a given 
location - the 'deep bass' is there, as long as you don't change 
presets... so the random stuff appears only when you come back to 
read out the patch. So I guess the values don't even make their way 
to the storage device?




--- In PolySix@yahoogroups.com, "Roman" <modular@...> wrote:
>
> hi,
> I don't think your RAM is damaged, try to find broken traces on the 
PCB
> leading to it. If some of them are damaged by battery leakage, 
writing a
> patch will actually write random stuff to the RAM, same thing when 
trying to
> read a patch. It's OK for RAM to work at smaller voltage, because 
it's
> powered via diode. Although I'd expect something like 4.5V and not 
4.
> It's hard to find replacement chip. I made a small adaptor, that 
takes
> typical RAM and converts to TC5514 pinout, pictures included.
> BTW, desoldering RAM can add more damage to the board if you're not
> carefull. OTOH it can fix some problems if there was some 
intermitent
> contact at some of the RAM leads.
> 
> Roman
> 
> ----- Original Message -----
> From: "sputnik979" <sputnik979@...>
> To: <PolySix@yahoogroups.com>
> Sent: Tuesday, June 27, 2006 8:43 PM
> Subject: [PolySix] Memory failure, S-RAM suspected.
> 
> 
> > Hi folks!
> >
> > My Polysix after battery leakage had the typical symtomps you 
might
> > expect.
> >
> > After having cleaned & resoldered the guts everything's fine 
apart from
> > the memory;
> > I create a patch, I press WRITE, I choose the location. Seems OK. 
But
> > just click another patch, then come back to the one I just saved -
 and
> > it's not there. A new 3.6V battery has been installed, but it is 
not
> > the matter of battery, beacause we are talking about doing this 
when
> > the synth is still operatnig, being plugged, so it has all the 
power
> > needed all the time.
> >
> > I'm inclined to think the TC5514 S-RAM chip is the culprit, 
because all
> > the chips keep voltage of 5V whereas this one has just 4V.
> >
> > What do you think ? What replacement part for TC5514 should I 
look for?
> > I've heard about Intersil HM6514 and Nec uPD444c (D444C-6514) but 
are
> > these really the only ones? I came across some chips 
with 'similar'
> > characteristics and I really would like to avoid importing the 
above
> > mentioned ICs.
> >
> > I'm not a tech, but a tech's opinion would be greatly appreciated 
and

> > helpful.
> >
> >   cheers
> >   aero

you may be right. Although it's a matter of one bit corrupted to
dramatiacally change the sound - imagine altered MSB of filter sutoff.
If you try to call pathces from 1-8 and the sound is the same, that could
mean that your RAM is not responding, or CS line to it is broken. If the
patches differ, but everytime you recall them they are more or less not
changed, that means RAM is OK, but something is wrong with writing it. Maybe
WE trace broken.
You could also try to measure power supply current of the ram. This 4V you
mention is worrying me. If it's considerably high (like a few mA) it may
suggest that RAM is really broken, possibly by electrostatic discharge.
Another way of testing is is to measure RAM power supply voltage when the P6
is powered off. It should be only 0.2-0.3V lower than battery voltage. If
it's 0.7V or more, that's a sign that something is wrong with the RAM.

Roman

----- Original Message -----

From: "sputnik979" <sputnik979@yahoo.com>
To: <PolySix@yahoogroups.com>
Sent: Friday, June 30, 2006 11:17 AM
Subject: [PolySix] Re: Memory failure, S-RAM suspected.


> Hi !
> The case is that it is my tech who's doing all the dirty work ;) I'm
> just managing & providing insights, let's call it. He has schematics
> and he knows what he's doing; he replaced the bad SN chips and
> resoldered all the bad traces so that now all formerly dead functions
> like octave switching, subosc, ADSR, cutoff, attenuator work fine.
> Now he's sort of asking me what to do, because all the traces seem
> fine, and this one IC is diffferent from others in the way of keeping
> 4V. So we have a complementary cooperation here as you see ;)
> And the question of random patches/values:
> If I create let's say a deep bass patch and save it to a given
> location - the 'deep bass' is there, as long as you don't change
> presets... so the random stuff appears only when you come back to
> read out the patch. So I guess the values don't even make their way
> to the storage device?
>
>
>
>
> --- In PolySix@yahoogroups.com, "Roman" <modular@...> wrote:
> >
> > hi,
> > I don't think your RAM is damaged, try to find broken traces on the
> PCB
> > leading to it. If some of them are damaged by battery leakage,
> writing a
> > patch will actually write random stuff to the RAM, same thing when
> trying to
> > read a patch. It's OK for RAM to work at smaller voltage, because
> it's
> > powered via diode. Although I'd expect something like 4.5V and not
> 4.
> > It's hard to find replacement chip. I made a small adaptor, that
> takes
> > typical RAM and converts to TC5514 pinout, pictures included.
> > BTW, desoldering RAM can add more damage to the board if you're not
> > carefull. OTOH it can fix some problems if there was some
> intermitent
> > contact at some of the RAM leads.
> >
> > Roman
> >
> > ----- Original Message -----
> > From: "sputnik979" <sputnik979@...>
> > To: <PolySix@yahoogroups.com>
> > Sent: Tuesday, June 27, 2006 8:43 PM
> > Subject: [PolySix] Memory failure, S-RAM suspected.
> >
> >
> > > Hi folks!
> > >
> > > My Polysix after battery leakage had the typical symtomps you
> might
> > > expect.
> > >
> > > After having cleaned & resoldered the guts everything's fine
> apart from
> > > the memory;
> > > I create a patch, I press WRITE, I choose the location. Seems OK.
> But
> > > just click another patch, then come back to the one I just saved -
>  and
> > > it's not there. A new 3.6V battery has been installed, but it is
> not
> > > the matter of battery, beacause we are talking about doing this
> when
> > > the synth is still operatnig, being plugged, so it has all the
> power
> > > needed all the time.
> > >
> > > I'm inclined to think the TC5514 S-RAM chip is the culprit,
> because all
> > > the chips keep voltage of 5V whereas this one has just 4V.
> > >
> > > What do you think ? What replacement part for TC5514 should I
> look for?
> > > I've heard about Intersil HM6514 and Nec uPD444c (D444C-6514) but
> are
> > > these really the only ones? I came across some chips
> with 'similar'
> > > characteristics and I really would like to avoid importing the
> above
> > > mentioned ICs.
> > >
> > > I'm not a tech, but a tech's opinion would be greatly appreciated
> and
> > > helpful.
> > >
> > >   cheers
> > >   aero
>
>
>
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>
>
>
>

I gather that by "WE" you mean WRITE ENABLE, but what is "CS line" ? 


--- In PolySix@yahoogroups.com, "Roman" <modular@...> wrote:


you may be right. Although it's a matter of one bit corrupted to
dramatiacally change the sound - imagine altered MSB of filter sutoff.
If you try to call pathces from 1-8 and the sound is the same, that 
could mean that your RAM is not responding, or CS line to it is 
broken. If the patches differ, but everytime you recall them they are 
more or less not changed, that means RAM is OK, but something is 
wrong with writing it. Maybe WE trace broken.
You could also try to measure power supply current of the ram. This 
4V you mention is worrying me. If it's considerably high (like a few 
mA) it may suggest that RAM is really broken, possibly by 
electrostatic discharge. Another way of testing is is to measure RAM 
power supply voltage when the P6 is powered off. It should be only 
0.2-0.3V lower than battery voltage. If it's 0.7V or more, that's a 
sign that something is wrong with the RAM.

> 
> Roman

It's me again. I found a tiny little dot of acid on one of those points 
in CN06 connector. This is the area where the upper boards of 
controls&knobs are connected to the main cpu board as you know. Could 
that be the culprit of my memory problem ? Maybe 'Write Enable' track 
goes through one of these points ? See picture:
[ http://img95.imageshack.us/my.php?image=poly6boardij0.jpg ]

depending on which pin it is, you may get trouble selecting some parameters
like switches (octave, wave etc.) and baks, presets, and "write" and "write
enable" too.
So yes, it may be the reason.
Basicaly majority of faults in synths comes from flaky connectors. P6 is
exception here - it's designed to have the battery leakage.

Roman

----- Original Message -----

From: "sputnik979" <sputnik979@yahoo.com>
To: <PolySix@yahoogroups.com>
Sent: Tuesday, July 25, 2006 3:23 PM
Subject: [PolySix] Re: Memory failure, S-RAM suspected.


> It's me again. I found a tiny little dot of acid on one of those points
> in CN06 connector. This is the area where the upper boards of
> controls&knobs are connected to the main cpu board as you know. Could
> that be the culprit of my memory problem ? Maybe 'Write Enable' track
> goes through one of these points ? See picture:
> [ http://img95.imageshack.us/my.php?image=poly6boardij0.jpg ]
>
>
>
>
>
>
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> Yahoo! Groups Links
>
>
>
>
>
>
>

CS is "chip select".

----- Original Message ----- 

From: "sputnik979" <sputnik979@yahoo.com>
To: <PolySix@yahoogroups.com>
Sent: Sunday, July 23, 2006 2:55 PM
Subject: [PolySix] Re: Memory failure, S-RAM suspected.


> I gather that by "WE" you mean WRITE ENABLE, but what is "CS line" ? 
> 
> 
> --- In PolySix@yahoogroups.com, "Roman" <modular@...> wrote:
> 
> 
> you may be right. Although it's a matter of one bit corrupted to
> dramatiacally change the sound - imagine altered MSB of filter sutoff.
> If you try to call pathces from 1-8 and the sound is the same, that 
> could mean that your RAM is not responding, or CS line to it is 
> broken. If the patches differ, but everytime you recall them they are 
> more or less not changed, that means RAM is OK, but something is 
> wrong with writing it. Maybe WE trace broken.
> You could also try to measure power supply current of the ram. This 
> 4V you mention is worrying me. If it's considerably high (like a few 
> mA) it may suggest that RAM is really broken, possibly by 
> electrostatic discharge. Another way of testing is is to measure RAM 
> power supply voltage when the P6 is powered off. It should be only 
> 0.2-0.3V lower than battery voltage. If it's 0.7V or more, that's a 
> sign that something is wrong with the RAM.
> 
> > 
> > Roman
> 
> 
> 
> 
> 
> 
> 
> 
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
>