Joining Keyboards 2

Hi Folks,
Joining 2 Keyboards – a different style of keyboard.
Please not this method is only for this type of keyboard but does give some idea of how to perform 
the same operations on other keyboard types.
Tools Required :-
Rule
Scriber
Sliding Square (small)
Square
Large Hacksaw
Small Hacksaw
Screwdrivers
Drill and Drill Bits
Metal File
Centre Punch
Vice
Self Tapping Screws
Tools Optional :-
9" Grinder with Metal Cutting Disc
5" Grinder with Metal Grinding Disc
Grinder Stand for 9" Grinder
Electric Welder
Vernier Calipers

Here is where we start.

Picture 1

The keyboard before I remove the unwanted components.


 
Picture 2

Here you can see that the contacts are driven from the underside of the keyboard and a lot of spare 
components that can be removed.
Remove all unwanted components and the spring contact carrier before going any further, you cannot 
remove the bus rails yet as they are screwed in from underneath the keys!!!
Who thought of that brilliant bit of design I wonder???

Picture 3

Be careful at this point as the bus bars are still in place underneath and a bit fragile.
This picture shows how the keys are removed, they are held in by a copper strip that forms part of the 
spring mechanism.
The strips and keys have some glue on them where they slide in, so scrape this off first.
To remove the strips just push down on the protruding end and pull out.
If you have removed the components on the underside first the keys can them be pulled off.

Picture 4

Once the keys are removed you can get at the bus bar holding screws, remove the bus bar so you 
know have a clean carriage for cutting.
 
Picture 5

Now use a square to establish a line to cut the steel base plate of at the required length for the extra 
keys.
Also cut the base plate to make a suitable sized joint when pushed up against the un-cut plate, you 
will also need to trim the un-cut plate to make the key spacing correct.
At this point when cutting the frames you will need to cut halfway between the key fulcrum slots to 
enable the correct spacing when re-joining the frames, this is where the vernier calliper comes in 
useful.
This is where the 9" grinder in a bench stand really becomes useful, with careful adjustment of the 
fence you can cut the frames nice and straight to get a good clean joint.


Picture 6 
Now cut the spare aluminium lengths that you removed earlier to the full base plate new length.
Some holes will line up but some will need re-drilling, once that is done push the altered base plates 
together and secure with screws to the back plates.


Picture 7
Thus producing a 61 note base plate.
 
Picture 8

Now the bus bars can be put back on after cutting the bus wires a bit shorter and pulling them back 
into the support nearest the joint.

They can be pulled back about half way through the holder to allow the rails from the short bus bar to 
be pushed in halfway.

At some point these rails will be better soldered together at the joint or separate earth connection 
made were there is a join. 
 
Picture 9

Now the remaining bus bars can be cut down to the required length and the supports slide along into 
the position required for the short base extension
 
Two new holes will need to be drilled at the end.

The keys can then be cleaned and replaced.

Now after just cutting a little off the contact holders they to can be replaced, again the holes will 
mostly line up but one new hole will be required.

Picture 10

That then produces a nice tidy 61 note keyboard.
My next job is to pull the return wires out of their supports and give them a good clean along with the 
spring contacts, then reassemble.
All that is then left to do is remove the old unwanted components and join up the 3 of the spring 
contacts for each key. 
This step is not really necessary but will give me 3 chances of a key making a good contact when 
pressed.
I hope that gives you some idea of how to join keyboards, some are relatively straight forward as this 
one is but some are a real nightmare as I hope to show you in the next article.
Please let me know if this has been useful or if you have any questions.

Martin   martin@end-task.com