Post by Time Lord on Mar 30, 2008 17:30:06 GMT -5
Dirty key contacts are a common problem in organs and some old synths. I asked Karl about the Wurly organ that we bought (circa 1983) and he sent me the following advise on dealing with this pesky problem and said that I could share it here...
"If there is a circuit board under the keys it is most likly a Keydeck with rubber bumps
coated with carbon which close a circuit when the key is depressed. I dont think you will hurt anything if you open this up, as organ keydecks are supposed to be serviced from time to time. Some are even on hinges to allow you to flip them up. Look for screws or bolts
at the bottom of the organ. A lot of times keys are self cleaning. and repeated playing will bring them back.
There are several types of keydeck contacts here are a some of the most likely you have in an early 1980 keydeck.
If it is the rubber type then carfully remove it. As long as you are doing this you might as well clean all of them. It may be many little cups or long strips with individual rubber cups
built in. Take all these off carefully noting the way they were positioned. Soak them in alcohol for a few hours. While they are soaking clean all the contacts on the circuit board
with alcohol as well. Take the rubber out of the alcohol and let the whole mess dry out overnight. If you put it back together right now it will probobly not work. When you put it back together take careful note to line everything up carefully. A lot of these have little rubber pins which line up to holes in the circuit board, which makes this easy. Put everything back together and you should be in good shape. If not look for broken wires
and re-solder them back.
If you find a wire buss with little stiff wires " sometimes called J hooks " which close the circuit, then the best thing to do is use a pencil eraser to CARFULY clean the spot where the wire touches the buss. This goes for any older keydeck type with J-hooks. Be careful not to break them. If any arre broken then go to your local hobby store wich sells RC
Airplanes. They usually sell sell stiff "spring steal wire" which you can bend with a needle nose pliers, this is is usually solderded into the circuit board.
If you find small diameter springs instead of J hooks the pencil eraser works here also.
One must be extreamly careful with these as they can be bent or broken very easily.
You find these on things like a polymoog or hey, my old toccata. If one gets broken
I know of no replacement but usually they are longer then they need to be and can be
unsoldered "using solder wick" and moved out further to make contact.
And finally if its a B3 go down to Radio XXXXX and get a can of contact cleaner and spray
all key contacts and drawbar contacts while moving them. This usually fixes " or ruins to some guys " the key click problems."
Thanks Karl
"If there is a circuit board under the keys it is most likly a Keydeck with rubber bumps
coated with carbon which close a circuit when the key is depressed. I dont think you will hurt anything if you open this up, as organ keydecks are supposed to be serviced from time to time. Some are even on hinges to allow you to flip them up. Look for screws or bolts
at the bottom of the organ. A lot of times keys are self cleaning. and repeated playing will bring them back.
There are several types of keydeck contacts here are a some of the most likely you have in an early 1980 keydeck.
If it is the rubber type then carfully remove it. As long as you are doing this you might as well clean all of them. It may be many little cups or long strips with individual rubber cups
built in. Take all these off carefully noting the way they were positioned. Soak them in alcohol for a few hours. While they are soaking clean all the contacts on the circuit board
with alcohol as well. Take the rubber out of the alcohol and let the whole mess dry out overnight. If you put it back together right now it will probobly not work. When you put it back together take careful note to line everything up carefully. A lot of these have little rubber pins which line up to holes in the circuit board, which makes this easy. Put everything back together and you should be in good shape. If not look for broken wires
and re-solder them back.
If you find a wire buss with little stiff wires " sometimes called J hooks " which close the circuit, then the best thing to do is use a pencil eraser to CARFULY clean the spot where the wire touches the buss. This goes for any older keydeck type with J-hooks. Be careful not to break them. If any arre broken then go to your local hobby store wich sells RC
Airplanes. They usually sell sell stiff "spring steal wire" which you can bend with a needle nose pliers, this is is usually solderded into the circuit board.
If you find small diameter springs instead of J hooks the pencil eraser works here also.
One must be extreamly careful with these as they can be bent or broken very easily.
You find these on things like a polymoog or hey, my old toccata. If one gets broken
I know of no replacement but usually they are longer then they need to be and can be
unsoldered "using solder wick" and moved out further to make contact.
And finally if its a B3 go down to Radio XXXXX and get a can of contact cleaner and spray
all key contacts and drawbar contacts while moving them. This usually fixes " or ruins to some guys " the key click problems."
Thanks Karl