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this description is not yet complete - more details coming soon

this is how i replaced the mostly functional yet constantly decaying keypad on my beloved Sequential Circuits Prophet 600.
where did i get a replacement keypad?   from Technology Transplant. they sell and make all kinds of neat stuff for older synths. including re-engineering and manufacturing parts that are no longer available - like this keypad.
they do business (so far) exclusively on eBay under the name chipforbrains - click on the name to see what auctions he has going at the moment. they also have a website but there isn't much there yet except for a few slightly cryptic and very tantalizing tidbits of info.


 step 1: UNPLUG THE PROPHET 600, you know, the power cable, take it out.

step 2: make sure it's unplugged! unplug everything.

now for the 2nd step 1:

remove arp speed knob. pull straight up.
 old keypad

2. AFTER you unplug it, remove the top 2 screws from both left and right side. this will release the entire control panel. it is hinged at the back and will open up like a treasure chest
 remove screws

3
damage!
see how my old keypad is busted? especially when i peel it up like that.
 peeling top layer

4
you don't have to do this, i'm just peeling it back to show where the ribbon cable goes through the face of the panel. the little tan area is an "adhesive-free zone"
 reveal the rabbit hole

5
behold. the layers
 the layers revealed

6
carefully lift the lid, let it come to rest all the way open. it should hang there without a problem (or you can prop it up a little with something that won't scratch), and here's what you're looking for; where the ribbon meets the circuit board
 where the ribbon meets the board

7
remove the ribbon cable. gently but firmly, might have to rock it back and forth a little.
 gently remove ribbon

8
there's the ribbon cable descending into the face of the synth
 old pad loose

9
and again from a little farther back
 old pad loose 2

10
now you can see both sides
 through the face

11
it sees us

you can clean the old adhesive off with isopropyl (rubbing) alcohol.
 naked face

12
the neat shipping box, from Hong Kong
 the long box

13
old keypad on the left, short ribbon cable

new keypad on the right, much longer ribbon cable. (that little white spot on the cable is a reflection, not a defect)

see steps 17 and 18 below to see how i dealt with the extra length
 comparing apples to newer apples

14
just for illustration
don't remove the backing yet
 from the back

15
insert the new ribbon down the slot
 down the rabbit hole

16
gently but firmly, once again, this may require using both hands to grasp either side of the ribbon to work it in completely (similar to removal - see step 7)
 insert, oh yeah

17
the ribbon cable is rather long. so long that it kinda sticks out. so i thought it might be best to tidy it up, lest it get squashed somehow when the control panel is rotated back into place. there are surely other methods of securing it, this is just the one i came up with at the moment.
that's a wire twist-tie, as you might find on a loaf of bread or a garbage bag. roughly rectangular shaped.
 macguyver inc.

18
folded the ribbon gently into this sandwich of curves. slide the twist-tie over it (may take some trial and error to get the size of the rectangle right)
 in you go, rascally ribbon

19
secured. relatively speaking.
 ribbon secured, i think

20
in place.

and now i can call up patch 22 whenever i like!
and 20
and 28
and 23
and 2anything
and anything2
 patch 22, finally!

21
an alternate view
 full working order

22
now, back in it's home on the rack. new keypad in place, knobs reinstalled.
lovely.
 home again, home again jiggity jig


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