Discussion about the Korg PolySix synthesizer

Greetings to all. My name is Jim and I'm new to this group. First, I 
want to thank everyone whose info and replies I have been reading 
here in Polysix land. You people are a godsend and are very familiar 
with this particular beast and I thank you for all of your ideas for 
the repair of my Polysix (Old Crow, you especially!). This really is 
the information age at its best! As for me, I am a "munician"- in 
other words, I am a musician/technician, and over all gadget freak. 
For some reason, over the last few years I have been relentlessly 
collecting synthesizers and keyboards, but that's another topic all 
together.  And now on to my repair problem...
I bought a Polysix off of eBay which is in very good condition except 
for a few dings to the wood sides. This unit was non-functional when 
it arrived due to the battery corrosion problem. The strange thing is 
that the battery didn't leave a puddle of corrosion under it, it just 
caused many, many of the via holes and traces covered with dull 
grainy appearance. This occurred over at least half of the component 
side of the board (the battery still looks fine and works). So, I had 
to repair a bunch of traces with jumper wire and also used my 
conductive pen (try it!), after which time all of the funtions of the 
keyboard now operate with the exception of ONE ANNOYING THING- no 
memory funcion. In other words, when I tweak a patch the way I want 
it and then store it it vanishes when I change banks and then go back 
to it. Also, when I load a tape dump in it accepts it, but does not 
appear in memory. I traced this down to a corroded +5 volt supply pin 
on IC 32. When I repaired this problem it still wouldn't work. Plus, 
when shut off the circuit draws about 3/4 of an Amp from the battery- 
enough to kill any back-up battery quickly. When I disconnected the 
+5 to the memory chip, the current draw problem goes away. Plus, I 
checked IC 25 gate chip, and it works fine. The only thing that can 
cause this, in my mind, is a faulty TC5514APL-3 SRAM. DOES ANYONE 
KNOW WHERE I CAN GET ONE OF THESE CHIPS? Are there any substitutes? 
All you techies out there, please help! Thanks for reading this very 
long post. Take care! ~JIM

Hi,

i\ufffdm sure that you will not find easy a 5114 RAM (if, then to a horrible 
price), just take the 2114, it\ufffds the same (1K*4)

The 5114 was produced by Philips, the 2114 is manufactured by National 
Semiconductor or Mitsubishi.

Stef


springpan wrote:

>Greetings to all. My name is Jim and I'm new to this group. First, I 
>want to thank everyone whose info and replies I have been reading 
>here in Polysix land. You people are a godsend and are very familiar 
>with this particular beast and I thank you for all of your ideas for 
>the repair of my Polysix (Old Crow, you especially!). This really is 
>the information age at its best! As for me, I am a "munician"- in 
>other words, I am a musician/technician, and over all gadget freak. 
>For some reason, over the last few years I have been relentlessly 
>collecting synthesizers and keyboards, but that's another topic all 
>together.  And now on to my repair problem...
>I bought a Polysix off of eBay which is in very good condition except 
>for a few dings to the wood sides. This unit was non-functional when 
>it arrived due to the battery corrosion problem. The strange thing is 
>that the battery didn't leave a puddle of corrosion under it, it just 
>caused many, many of the via holes and traces covered with dull 
>grainy appearance. This occurred over at least half of the component 
>side of the board (the battery still looks fine and works). So, I had 
>to repair a bunch of traces with jumper wire and also used my 
>conductive pen (try it!), after which time all of the funtions of the 
>keyboard now operate with the exception of ONE ANNOYING THING- no 
>memory funcion. In other words, when I tweak a patch the way I want 
>it and then store it it vanishes when I change banks and then go back 
>to it. Also, when I load a tape dump in it accepts it, but does not 
>appear in memory. I traced this down to a corroded +5 volt supply pin 
>on IC 32. When I repaired this problem it still wouldn't work. Plus, 
>when shut off the circuit draws about 3/4 of an Amp from the battery- 
>enough to kill any back-up battery quickly. When I disconnected the 
>+5 to the memory chip, the current draw problem goes away. Plus, I 
>checked IC 25 gate chip, and it works fine. The only thing that can 
>cause this, in my mind, is a faulty TC5514APL-3 SRAM. DOES ANYONE 
>KNOW WHERE I CAN GET ONE OF THESE CHIPS? Are there any substitutes? 
>All you techies out there, please help! Thanks for reading this very 
>long post. Take care! ~JIM
>
>
>To unsubscribe from this group, send an email to:
>PolySix-unsubscribe@egroups.com
>
>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6 
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
>
>
>
>  
>

On Sat, 15 Feb 2003, springpan <springpan@yahoo.com> wrote:

> cause this, in my mind, is a faulty TC5514APL-3 SRAM. DOES ANYONE 
> KNOW WHERE I CAN GET ONE OF THESE CHIPS? Are there any substitutes? 

  Go to http://www.jameco.com/

  Search for item# 43238 (HM6514 1K x 4 CMOS static RAM)

  That is what I use for repairs.  It is equivalent to the TC5514 and the 
uPC444.  DON'T use a 2114.  That will drain the backup battery in 30 
minutes.

Crow
/**/

>   Go to http://www.jameco.com/
> 
>   Search for item# 43238 (HM6514 1K x 4 CMOS static RAM)

I too am going to get one of these as my Polysix is right now just a 
preset machine (hey, at least they are the presets I programmed into 
it!).

I was having a similar problem where my patches would change randomly 
and would usually snap back to what they were supposed to be if I hit 
the bank/program button where they were stored. Battery was replaced 
4 years ago and I had no problems for 3 1/2 years. Anyway, now the 
patches all sound fine every time, but I can't edit anything except 
the octave selection. So I will replace the IC32. 

But, Question - isn't there a special tool for removing them rather 
than using a (static-free) screwdriver? I want to be carefull not to 
damage the board when I remove the old chip before putting in the 
new. Or if there are any techniques I should know, that would be 
appreciated.

Thanks,

Ells

Ells,
Be careful! If your Polysix will hold its presets when they are 
changed or the unit is turned off, I would say offhand that the SRAM 
chip is probably okay. You might be wasting your money on buying a 
new one. If you can't edit your sounds while in manual control, then 
there is something else wrong. My SRAM chip was indeed bad, but I was 
still able to use manual and tweak the sounds- I just couldn't save 
anything. Even if your battery is only a couple of years old, you 
should start by making sure it hasn't leaked again on that board. 
Just because the battery will hold its voltage doesn't mean that its 
NOT leaking. Much weirdness that you describe can result...
By the way, cutting the legs off an old IC IS the safe way to remove 
it - that prevents pressure from being applied to the solder pads and 
plated-through holes, resulting in board damage. If you cut the body 
of the IC off first, then you can remove each lead carefully one at a 
time with wicking braid.  Of course, you could spend a few hundred 
bucks and buy a fancy unsoldering station made by Hakko, Ungar, 
Weller, etc. but that chip only costs about two bucks new anyway. 
Happy tinkering with your Polysix! ~JIM



--- In PolySix@yahoogroups.com, "yrbesque" <ehall@b...> wrote:
> 
> >   Go to http://www.jameco.com/
> > 
> >   Search for item# 43238 (HM6514 1K x 4 CMOS static RAM)
> 
> I too am going to get one of these as my Polysix is right now just 
a 
> preset machine (hey, at least they are the presets I programmed 
into 
> it!).
> 
> I was having a similar problem where my patches would change 
randomly 
> and would usually snap back to what they were supposed to be if I 
hit 
> the bank/program button where they were stored. Battery was 
replaced 
> 4 years ago and I had no problems for 3 1/2 years. Anyway, now the 
> patches all sound fine every time, but I can't edit anything except 
> the octave selection. So I will replace the IC32. 
> 
> But, Question - isn't there a special tool for removing them rather 
> than using a (static-free) screwdriver? I want to be carefull not 
to 

> damage the board when I remove the old chip before putting in the 
> new. Or if there are any techniques I should know, that would be 
> appreciated.
> 
> Thanks,
> 
> Ells

> Ells,
> Be careful! If your Polysix will hold its presets when they are 
> changed or the unit is turned off, I would say offhand that the SRAM 
> chip is probably okay. You might be wasting your money on buying a 
> new one. If you can't edit your sounds while in manual control, then 
> there is something else wrong.

Thanks for the heads up, Jim! I was wondering about that myself which is why I posted. I can't edit in Manual mode either. Just have a kind of blip sound that can't be tweaked. The odd thing is is that the Polysix used to not hold patches properly until it warmed up for about 20 minutes and I COULD edit them at that time. That was last fall and it sounded very much like the Old Crow's description of a bad IC32 chip.

Then just recently it started retaining the patches right at boot up and they are all fine except now I *can't* edit them!

> My SRAM chip was indeed bad, but I was 
> still able to use manual and tweak the sounds- I just couldn't save 
> anything.

Yes, we had the opposite problem in a way.

> Even if your battery is only a couple of years old, you 
> should start by making sure it hasn't leaked again on that board. 
> Just because the battery will hold its voltage doesn't mean that its 
> NOT leaking. Much weirdness that you describe can result...

Well I had the Varta replaced with a Lithium battery so there should not be a leakage problem. But perhaps it took a few years for some tiny bit of corrosion from the orignal battery finally is eating away at some trace??? (it was just starting to corrode but the Poly worked fine for a few years beginning at that time in '99 when the battery was changed) 

> By the way, cutting the legs off an old IC IS the safe way to remove 
> it - that prevents pressure from being applied to the solder pads and 
> plated-through holes, resulting in board damage. If you cut the body 
> of the IC off first, then you can remove each lead carefully one at a 
> time with wicking braid.

Great to know, thanks again Jim! 
But it sounds like something else is wrong. Anyone have any ideas? I had the Poly midied and everything so it seems like a waste to let it just be a preset machine.

- Ells


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

Dear Old Crow,

I was wondering if you had an idea as to what I should do next. Thought the IC32 in my Polysix was going up, but appears not (see below). Perhaps there are corroded traces on the board just not readily visible?

Thanks for any insight. Your site is great, I cleaned my key contacts with its instruction.

- Ells
===========

> Ells,
> Be careful! If your Polysix will hold its presets when they are 
> changed or the unit is turned off, I would say offhand that the SRAM 
> chip is probably okay. You might be wasting your money on buying a 
> new one. If you can't edit your sounds while in manual control, then 
> there is something else wrong.

Thanks for the heads up, Jim! I was wondering about that myself which is why I posted. I can't edit in Manual mode either. Just have a kind of blip sound that can't be tweaked. The odd thing is is that the Polysix used to not hold patches properly until it warmed up for about 20 minutes and I COULD edit them at that time. That was last fall and it sounded very much like the Old Crow's description of a bad IC32 chip.

Then just recently it started retaining the patches right at boot up and they are all fine except now I *can't* edit them!

> My SRAM chip was indeed bad, but I was 
> still able to use manual and tweak the sounds- I just couldn't save 
> anything.

Yes, we had the opposite problem in a way.

> Even if your battery is only a couple of years old, you 
> should start by making sure it hasn't leaked again on that board. 
> Just because the battery will hold its voltage doesn't mean that its 
> NOT leaking. Much weirdness that you describe can result...

Well I had the Varta replaced with a Lithium battery so there should not be a leakage problem. But perhaps it took a few years for some tiny bit of corrosion from the orignal battery finally is eating away at some trace??? (it was just starting to corrode but the Poly worked fine for a few years beginning at that time in '99 when the battery was changed) 



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