Vintage Synth Repair

Dear list,
i bought recently a siel expander, dk-600 tabletop module version.
after messing with sysex informations found over the net i was able to program
it from my windows computer(despite what someone says, handshaking is not
a must, so programming it without the keyboard version is possible.)
So far i was happy.

Of course the day i opened the machine up i found the dreaded battery leakage
problem. I decided to try cleansing it and apparently succeded.
But soon it started behaving strangely, so i took it apart again and found
a capacitor leg broken! i don't have the facilities nor knowledge to solder
it on my own (i can hear you laughing) so i abandoned the quest.
Today, after a month of inactivity i pushed the on button and the poor synth
seems to be DEAD.

My humble questions are: can a single capacitor disconnected kill the machine?
i could run it without capacitor a month ago, the machine would freeze itself
after a minute or so.

Also i read about korg polysix not to touch the inside without antistatic
precautions not to burn cmos circuits. i dont know if it is the case, but
i didn't took any precaution. And anyway between dk600 life and death passage
i didnt touch it no more, so it must be something i did that killed it slowly
during the month of inactivity. It shows no sign of corrosion now, traces
are intact.

any advice anyone?
thanks, davide

Hi Davide

 

The question that needs answering is how did you clean up the dreaded
leaking battery?  Have you removed the batteries?  Before doing anything at
all disconnect the unit from any mains power.

 

The procedure I always follow with this scenario is to remove the batteries
and throw them away.  Then swab the affected area with warm water mixed with
bicarbonate of soda.  This alkali solution will neutralize the battery acid.
The battery contacts will need very careful attention to ensure that all
traces of the acid have been removed.

 

For solution quantities I use a small cup of warm water and a couple of
teaspoons full of bicarb.  I get my bicarb from the chemist in 500gm packs
and is medicinal quality.

 

Once you are sure that all traces of acid have gone swab the affected area
with clean water, dry off with a household paper towel and leave to dry in a
warm area - an airing cupboard is ideal.  Leave over night.

 

The following day replace with new batteries.  Switch on and see what
happens.

 

Now in your case the disconnected capacitor needs to be re soldered back
into place first.

 

Without knowing which capacitor has come adrift it is impossible to say
whether or not that could cause a completely dead situation, but yes it is
possible.

 

Hope this helps.

 

Regards

 

Brian G3OYU

 

  _____  

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of
pasquale.aprea@...
Sent: Thursday, 12 May, 2005 11:00
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] siel DK-600 expander

 

Dear list,
i bought recently a siel expander, dk-600 tabletop module version.
after messing with sysex informations found over the net i was able to
program
it from my windows computer(despite what someone says, handshaking is not
a must, so programming it without the keyboard version is possible.)
So far i was happy.

Of course the day i opened the machine up i found the dreaded battery
leakage
problem. I decided to try cleansing it and apparently succeded.
But soon it started behaving strangely, so i took it apart again and found
a capacitor leg broken! i don't have the facilities nor knowledge to solder
it on my own (i can hear you laughing) so i abandoned the quest.
Today, after a month of inactivity i pushed the on button and the poor synth
seems to be DEAD.

My humble questions are: can a single capacitor disconnected kill the
machine?
i could run it without capacitor a month ago, the machine would freeze
itself
after a minute or so.

Also i read about korg polysix not to touch the inside without antistatic
precautions not to burn cmos circuits. i dont know if it is the case, but
i didn't took any precaution. And anyway between dk600 life and death
passage
i didnt touch it no more, so it must be something i did that killed it
slowly
during the month of inactivity. It shows no sign of corrosion now, traces
are intact.

any advice anyone?
thanks, davide





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thanks a lot Brian!
i just bought bicarbonate of soda, i'll have another go at cleansing it soon.


The first time i did it i did use white vinegar as someone adviced me, then
rinsed it with water. 
the battery is still in place though, a 3v lithium one i suppose.
While vinegar is said to be effective against alkaline acid, i don't know
about lithiums,but no damaged should a little vinegar bath have done.

As for the capacitor, if you are curios, its the very first one at the left
of IC16. you can see it here http://www.freewebtown.com/savojr/dk600/pics/battery-removed.jpg.

Or just follow the link to "battery removed" from the main page of that dk600
help site http://beam.to/dk600. It's not an actual photo of my board.
The capacitor was soldered coupled with a resistance leg by leg.So the circuit
is still uninterrupted, there's only the resistance now to provide the conductive
bridge. 
I didn't remove the battery at first since i've yet to identify it looking
for replacement. Also i didn't notice the capacitor broke, so i did turn
the unit on experiencing that freeze after a couple minutes of play.

thanks, Davide

i don't know why while the links i posted work if typed in internetexplorer
address bar, they don't when clicked directly from my previous message. Don't
follow that links then, sorry. head to google instead and type :"siel dk-600
help/service center" in the search bar. the image is still the one after
"battery removed" link. if you are curios of course,i feel sorry thanks
davide

Hi Davide

 

A couple of points.  Firstly alkaline acid is a contradiction in terms!  A
substance is either acid OR alkaline it cannot be both.  Vinegar is acetic
acid and I would never ever recommend it to clean an electronic printed
circuit.

 

Secondly if the battery has leaked it is useless and will still leak and
cause trouble so get it out quickly and then clean up with the bicarb.

 

Without a circuit diagram it is impossible for me to suggest what that
capacitor is there for, perhaps someone else on this list who has worked on
the unit can identify it for us.

 

Regards

 

Brian G3OYU

 

  _____  

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of
pasquale.aprea@...
Sent: Thursday, 12 May, 2005 18:49
To: vintagesynthrepair@yahoogroups.com
Subject: RE: [vintagesynthrepair] siel DK-600 expander

 

thanks a lot Brian!
i just bought bicarbonate of soda, i'll have another go at cleansing it
soon.


The first time i did it i did use white vinegar as someone adviced me, then
rinsed it with water. 
the battery is still in place though, a 3v lithium one i suppose.
While vinegar is said to be effective against alkaline acid, i don't know
about lithiums,but no damaged should a little vinegar bath have done.

As for the capacitor, if you are curios, its the very first one at the left
of IC16. you can see it here
http://www.freewebtown.com/savojr/dk600/pics/battery-removed.jpg.

Or just follow the link to "battery removed" from the main page of that
dk600
help site http://beam.to/dk600. It's not an actual photo of my board.
The capacitor was soldered coupled with a resistance leg by leg.So the
circuit
is still uninterrupted, there's only the resistance now to provide the
conductive
bridge. 
I didn't remove the battery at first since i've yet to identify it looking
for replacement. Also i didn't notice the capacitor broke, so i did turn
the unit on experiencing that freeze after a couple minutes of play.

thanks, Davide 





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vintagesynthrepair-unsubscribe@yahoogroups.com
<mailto:vintagesynthrepair-unsubscribe@yahoogroups.com?subject=Unsubscribe> 
  
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ahah, i guess i can't say it is my poor english fault this time!
i must admit in shame i didn't know alkaline was synonimum with basic, i
thought it was a type of chemical mixture used in certain batteries! Let's
have one more read to that old physics book.

So i added acid to acid to my poor synth. Strangely the battery was still
able to hold the memory backed up, and board traces fortunately seem intact.

As for what concerns the diagrams i own them, but they are renomed for being
a total mess, I wont ask you to help me this further.
I'll cut and throw away that battery, then i'll apply the bicarbonate treatment.
I'll keep you informed, thanks Brian for your precious help, and see you
all!