The Kawai & Teisco Analog Synths Group

Did you read my last response ?

Are you rewiring the board ? did you replace all components at the 
battery area ?

The behavious could be due to a defected EEROM, if the battery hasn't 
leaked... but as this is the situation - look at the battery leakage 
as main suspect.


--- In kawai_sx210@yahoogroups.com, "Mark Daborn" <darkest.yugo@n...> 
wrote:
> Hi,
> 
> The restoration of my SX-210 continues furiously.
> Today my techie friend and i had the thing in bits testing and 
probing as much as we could.
> We eliminated quite a few components from our investigations but 
have reason to doubt the contents of the EPROM.
> 
> Does anybody have a copy of the program or know where i might find 
one? I have had a search on the net but as yet
> not found anything.
> 
> Could someone please help? Today my SX 210 almost made a sensible 
sound and it's boosted my efforts to fix it.

> I didn't realise how amazing the ensemble sounds!
> 
> Thanks for any help you can provide,
> Mark

http://www.oldcrows.net/~oldcrow/synth/korg/polysix/repair.html








--- In kawai_sx210@yahoogroups.com, "Mark Daborn" <darkest.yugo@n...> 
wrote:
> Hi,
> 
> The restoration of my SX-210 continues furiously.
> Today my techie friend and i had the thing in bits testing and 
probing as much as we could.
> We eliminated quite a few components from our investigations but 
have reason to doubt the contents of the EPROM.
> 
> Does anybody have a copy of the program or know where i might find 
one? I have had a search on the net but as yet
> not found anything.
> 
> Could someone please help? Today my SX 210 almost made a sensible 
sound and it's boosted my efforts to fix it.

> I didn't realise how amazing the ensemble sounds!
> 
> Thanks for any help you can provide,
> Mark

Can you describe the problem again ?

As far as I understand the problem is dead tones -
which doesn't come up at all when in Poly 8 mode (all keys respond 
and plays ok) and only exist when in Poly 4 mode, where the first 4 
keys pressed will play and the next 4 won't ?


--- In kawai_sx210@yahoogroups.com, "Mark Daborn" <darkest.yugo@n...> 
wrote:
> Hi, as this whole problem with my machine is due to battery 
leakage, i have already removed the nasty old Ni-Cad
> and replaced it. Ic's 7 and 8 have been replaced and most of the 
tracks  in the area  hard wired. All other tracks have been tested 
for continuity and appear okay.
> 
> The behaviour of the machine still suggests possibly a ground issue 
or a defective IC (or IC's!!). 
> 
> When played in poly mode we found there was a regular pattern to 
the silent notes. In poly 4 mode it was even more obvious. Basically 
4 notes on (as we played up the keyboard) then 4 off. However, 
cycling through the 8 voices when playing one key (that worked) 
showed no sign of a defective voice.
> 
> We have already eliminated the keyboard as a source of the problem.
> 
> It's looking likely that as it's getting the instructions to play a 
note ok, and the sound generation side of it is okay, the problem 
must lie somewhere  in between.
> 
> The plan, therefore, was to remove the possibility of the EPROM 
being corrupted, which has already had a new socket.
> 
> My friend has taken the service manual and is going to read it 
cover to cover hoping for divine inspiration!
> 
> Thanks for your help!
> 
> Mark.
>   ----- Original Message ----- 
>   From: gil_we 
>   To: kawai_sx210@yahoogroups.com 
>   Sent: Sunday, October 02, 2005 12:10 AM
>   Subject: [kawai_sx210] Re: Can anybody please help???
> 
> 
>   Did you read my last response ?
> 
>   Are you rewiring the board ? did you replace all components at 
the 
>   battery area ?
> 
>   The behavious could be due to a defected EEROM, if the battery 
hasn't 
>   leaked... but as this is the situation - look at the battery 
leakage 
>   as main suspect.
> 
> 
>   --- In kawai_sx210@yahoogroups.com, "Mark Daborn" 
<darkest.yugo@n...> 
>   wrote:
>   > Hi,
>   > 
>   > The restoration of my SX-210 continues furiously.
>   > Today my techie friend and i had the thing in bits testing and 
>   probing as much as we could.
>   > We eliminated quite a few components from our investigations 
but 
>   have reason to doubt the contents of the EPROM.
>   > 
>   > Does anybody have a copy of the program or know where i might 
find 
>   one? I have had a search on the net but as yet
>   > not found anything.
>   > 
>   > Could someone please help? Today my SX 210 almost made a 
sensible 
>   sound and it's boosted my efforts to fix it.
>   > I didn't realise how amazing the ensemble sounds!
>   > 
>   > Thanks for any help you can provide,
>   > Mark
> 
> 
> 
> 
>   SPONSORED LINKS Sampler  Electronic instrument  Synthesizer  
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> 
> 
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> 
>     a..  Visit your group "kawai_sx210" on the web.
>       
>     b..  To unsubscribe from this group, send an email to:
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of Service. 
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----------

It might be that as long as you don't change keys the assigner doen't 
change the assignment... you'll have to check with an audio probe 
which is the actual osc. playing. If they all play then the problem 
doesn't lay in the voice board probably.

Touch the ICs, is any of them way too hot ?
I had a similar problem on my Roland MKS-70 (voices sounded 
different, kind of "corrupt" as if they didn't get the correct data 
setting). The main CPU on the voice board was defected.

Are all main voltages correct ?



--- In kawai_sx210@yahoogroups.com, "Mark Daborn" <darkest.yugo@n...> 
wrote:
> Hi again!
> 
> Since my friend and i had a poke around, the behaviour  is slightly 
more predictable.
> 
> Basically the problem is this:
> 
> in poly 8 mode (playing up the keyboard from lowest C) only 3 out 
of eight notes play. As you continue up the keyboard the next three 
notes out of eight sound and so on. 
> 
> Thinking this might be simply dead voices, i played 8 notes on a 
single key that i knew worked (to cycle through the voices) and all 
eight key presses worked okay.
> 
> In poly 4 mode, you get four notes with a sound, four that dont 
(once again going up the keyboard).
> 
> Mono mode doesn't produce any sound at all.
> 
> There is also tonal variation between all the notes that do sound, 
as if the filter EG isn't getting the correct information. The EG 
works fine and does what it should when tested on a note that works.
> 
> On the top panel, when pressing certain switches, the LED's on 
other switches flicker weakly. This has lead me to consider an earth 
problem somewhere, possibly due to a defunct IC.
> 
> Next weekend we intend to get the oscilloscope out and track the 
signals through the machine.
> 
> We remain confident!!!
>  
>   ----- Original Message ----- 
>   From: gil_we 
>   To: kawai_sx210@yahoogroups.com 
>   Sent: Sunday, October 02, 2005 1:07 PM
>   Subject: [kawai_sx210] Re: Can anybody please help???
> 
> 
>   Can you describe the problem again ?
> 
>   As far as I understand the problem is dead tones -
>   which doesn't come up at all when in Poly 8 mode (all keys 
respond 
>   and plays ok) and only exist when in Poly 4 mode, where the first 
4 
>   keys pressed will play and the next 4 won't ?

Check *ALL* of the interconnects. My 240 did this when I first got it and I reseated the wires in all the IDC ribbon cables. Take the cable off the board and

Just another note here....don t worry about the contents of the eprom. If it was bad, the machine would do nothing at all because the cpu would be in constant

What is the problem on the Akai ?

--- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> 
wrote:
> Check *ALL* of the interconnects. My 240 did this when I first got 
it and
> I reseated the wires in all the IDC ribbon cables. Take the cable 
off the
> board and put it on a hard surface (not the pcb), with a small 
mallet and
> a miniature flate blade screwdriver tap the wires back into the IDC
> contacts. After doing that spray some contact cleaner into them and
> plug/unplug a couple times to clean the pins/contacts.
> 
> You have to keep in mind that the gas coming out of a dead NiCd 
battery
> is *bad* stuff and will get into everything and corrode the shit 
out of
> it. I just worked on a Poly 61 that had a bad battery in it for 
years and
> the damage was extensive. Many connectors were eaten up to the 
point of
> being not much left of the metal at all and ruined the wire from 
one end
> to the other (yes, the gas climbs up through wire inside the 
insulation).
> After repairing all the damage there was a logic problem on the cpu 
bd
> that I didn't feel like buying a service manual to find (hey, I 
paid $20
> for the thing) so its been gutted and will be a case/keyboard donor 
for a
> 6 osc. monosynth project I've had in mind for a while.
> 
> Kids.....get those damn NiCd's outta there now.
> 
> Also....if anyone's interested in some Akai AX80 parts lemme know. 
I'll
> prolly be parting one of these out soon if I can't get the switch
> matrix/display issues taken care of (no service manual available 
for this
> one).
> 
> 
> 
>   ----- Original Message -----
>   From: "Mark Daborn"
>   To: kawai_sx210@yahoogroups.com
>   Subject: Re: [kawai_sx210] Re: Can anybody please help???
>   Date: Sun, 2 Oct 2005 10:04:13 +0100
> 
> Hi, as this whole problem with my machine is due to battery 
leakage, i
> have already removed the nasty old Ni-Cadand replaced it. Ic's 7 
and 8
> have been replaced and most of the tracks  in the area hard wired. 
All
> other tracks have been tested for continuity and appear okay. The
> behaviour of the machine still suggests possibly a ground issue or a
> defective IC (or IC's!!). When played in poly mode we found there 
was a
> regular pattern to the silent notes. In poly 4 mode it was even more
> obvious. Basically 4 notes on (as we played up the keyboard) then 4 
off.
> However, cycling through the 8 voices when playing one key (that 
worked)
> showed no sign of a defective voice. We have already eliminated the
> keyboard as a source of the problem. It's looking likely that as 
it's
> getting the instructions to play a note ok, and the sound 
generation side
> of it is okay, the problem must lie somewhere in between. The plan,
> therefore, was to remove the possibility of the EPROM being 
corrupted,
> which has already had a new socket. My friend has taken the service
> manual and is going to read it cover to cover hoping for divine
> inspiration! Thanks for your help! Mark.
> 
>   ----- Original Message ----- From: gil_weTo:
>   kawai_sx210@y...: Sunday, October 02, 2005 12:10 AMSubject:
>   [kawai_sx210] Re: Can anybody please help???
>   Did you read my last response ?
> 
>   Are you rewiring the board ? did you replace all components at the
>   battery area ?
> 
>   The behavious could be due to a defected EEROM, if the battery 
hasn't
>   leaked... but as this is the situation - look at the battery 
leakage
>   as main suspect.
> 
> 
>   --- In kawai_sx210@yahoogroups.com, "Mark Daborn" 
<darkest.yugo@n...>
>   wrote:
>   > Hi,
>   >
>   > The restoration of my SX-210 continues furiously.
>   > Today my techie friend and i had the thing in bits testing and
>   probing as much as we could.
>   > We eliminated quite a few components from our investigations but
>   have reason to doubt the contents of the EPROM.
>   >
>   > Does anybody have a copy of the program or know where i might 
find
>   one? I have had a search on the net but as yet
>   > not found anything.
>   >
>   > Could someone please help? Today my SX 210 almost made a 
sensible
>   sound and it's boosted my efforts to fix it.
>   > I didn't realise how amazing the ensemble sounds!
>   >
>   > Thanks for any help you can provide,
>   > Mark
> 
> 
> 
> 
>   SPONSORED LINKS
>   Sampler Electronic instrument Synthesizer
>   Synthesizer music Electronic music Music sampler
> 
>   ------------------------------------------------------------------
--
> 
>   YAHOO! GROUPS LINKS
> 
>     *  Visit your group "kawai_sx210" on the web.
> 
>     *  To unsubscribe from this group, send an email to:
>       kawai_sx210-unsubscribe@yahoogroups.com
> 
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> 
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----- Original Message -----

From: gil_we 
To: kawai_sx210@...m
Subject: [kawai_sx210] Re: Can anybody please help???
Date: Mon, 03 Oct 2005 08:42:55 -0000

>What is the problem on the Akai ?

It powers up ok and operates, but the switch matrix is screwed up (last bank of option/preset switches don't work) even after installing real ribbon cables. If anyone's seen one of these opened up, they used .1" headers to connect the boards under the top panel with. This is not the greatest idea I've seen, vibration causes them to crack loose from the board. So some flexable ribbon usually takes care of that. Other than that, the parameter value led display is funky, segments don't change like they should (displays "8" most of the time). I identified a 40 pin ic that I believe handles both the panel switch scanning along with the display segments. I have never heard of it, so finding one would be next to impossible, but I do have a few sources for oddball parts I'll try before I scrap it.

Since I can't really program it I don't know what it can do sonically. It does have decent filters, oscillators (if they are really oscillators and not digitally created) are fairly flexable, and man.....ya gotta love those blue flourescent bargraph displays.

I know they're rare, but not really worth anything (I paid 50$ for it). Plus it's pretty beat up. I was hoping it was the AX60 (cem3394's) when a friend told me about it.


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I'm not saying that could not be the EEPROM, but I recall myself 
suspecting the EEPROM a few times in the past, where no other 
component gave any clue as for being bad - ending up finding another 
bad component, leaving the EEPROM being just fine ;)

It is alway easy to blame the EEPROM when all kind of strange thing 
happen - last time it was a bad CPU on the synth board of my MKS70...


--- In kawai_sx210@yahoogroups.com, "Mark Daborn" <darkest.yugo@n...> 
wrote:
>
> Hi,
> 
> The restoration of my SX-210 continues furiously.
> Today my techie friend and i had the thing in bits testing and 
probing as much as we could.
> We eliminated quite a few components from our investigations but 
have reason to doubt the contents of the EPROM.
> 
> Does anybody have a copy of the program or know where i might find 
one? I have had a search on the net but as yet
> not found anything.
> 
> Could someone please help? Today my SX 210 almost made a sensible 
sound and it's boosted my efforts to fix it.

> I didn't realise how amazing the ensemble sounds!
> 
> Thanks for any help you can provide,
> Mark
>