Crumar Performer - Keyboard Issues

[Low_Fi]

I recently purchased a Crumar Performer that has some keyboard issues. The bottom C is completely dead and the other 4 C's have a very long sustain, regardless of where the slider is positioned in the Strings section. All the other keys are fine. I've taken it apart and cleaned the contacts but that hasn't helped at all. Any ideas? Thanks!

[Maschinengeist]

My head is mush right now. I'll check my documents and come back to you as soon as possible (got lot of jobs so it might not be in the next 15 minutes).

[rhino]

if this keyboard uses the TDA1008 divider/keyers, they have very high impedance cricuts driving them. IF there are separate little cards for every two notes (six in all) that plug in to a main board, clean the contacts on them. if the dead C is because of a failed TDA chip, GOOD LUCK finding one.
Try Maschenegiest first.... he has lots of secret contacts (lol) !

[Low_Fi]

Thanks for your replies. Under each plastic key there's a little hole where a very thin piece of flexible wire is inserted. When you press the key it forces down the flexible wire which I'm assuming makes contact with the board underneath but I didn't pull the keyboard apart that much because it looked incredibly difficult to reach. There's a metal plate between the plastic keys and where the flexible wire is connected to the board. It looks like I'd have to remove every single key to be able to remove that metal plate and expose the board underneath (doesn't look to be an easy task because there are brackets hindering access to certain keys that make disassembly even more difficult). I sprayed some contact cleaner into each hole where the flexible wire is poking out under the keys in the hopes that the cleaner would do it's thing. Unfortunately after assembly the the low C is still dead and all the other C's still sustain longer than they should. I've cleaned contacts before on other synths but this is the most awkward and difficult to reach keybed I've seen so far (not that I'm an experienced synth tech by any stretch). Hopefully Maschinengeist will have some news.

[mung]

rofl i had that exact problem with the Crumar Orchestrator that I bought...except I paid some guy $100 to fix it.

[Maschinengeist]

Try Maschenegiest first.... he has lots of secret contacts (lol) !

LOL?

Well, that's part of my job. No single supplier can have every possible components/parts in stock or available to him/them. I try to establish the biggest supplier network as possible so I can serve my customers better and faster too. That's almost a full-time job to establish contact. Yeah, I've got a few "secret" ones (they cannot be reached by the Net).

Thanks for the menion. I really do appreciate.

Ok, I didn't have time to check this out (I'm alone in my business and highly sollicitated too). But I have not forgotten you. Should be back this weekend.

[Maschinengeist]

DOUBLE POST. SORRY!

[rhino]

one of the first signs of mental decline is repeating yourself.

[rhino]

one of the first signs of mental decline is repeating yourself.

[rhino]

enought funny (?) stuff.

it looks (on paper) that ahere are six keyer boards (one handles the Cs and F-sharps) on many old TOS style polys (like ELKA) they were plugged into a main board with PC edge contacts... like a modern computer. any resistance in the sustain line contact (from oxidation or other crud) would make the note sustain longer. if it was just one note, i would say maybe a dead diode, but if all the keyers (on that card) use a common sustain "drain" line, my guess is still a bad connection.



still a bad connection.




connection.

[Maschinengeist]

one of the first signs of mental decline is repeating yourself.

Oops, I didn't notice the double post. Damn this keyboard... and damn the meds as well.

[Low_Fi]

Thanks for the tip, rhino!! Makes sense...sounds like you're onto something. I don't recall seeing separate boards like you're describing but I'll pull everything apart again and take a look. I really hope it's just a bad contact that can be cleaned since there are no reputable synth techs in my area that I'm aware of.

[Low_Fi]

Here's a shot I took of the board underneath the keybed:



I can't locate any boards that are similar in concept to PCI boards in PC's. I do, however, see 12 distinct sections on the board consisting of two sets of resistors at the top, followed by an eeprom, and next some capacitors, and finally more resisters. I'm wondering if I should spray some contact cleaner into where the eeprom's are sitting? I tried pushing them in since some looked like they inched out due to chip creep but they didn't budge. If I have to end up taking this to an actual tech (first have to find one) then so be it but I just hate giving somebody $100.00 to fix something that consists of 5 minutes of them diagnosing the issue and soldering for another 5. That's $100 that could've gone to more gear

[rhino]

well, so much for trying to diagnose something by text! i'll try to find a schematic if Maschenegiest dosen't find one first.


------------------------------------------------- VERY old joke from the 50's--------------------------------------

A company's new computer goes down. A tech service person is called in.
He looks at thge computer mainframe for a minute, then gives it a good kick.
The computer starts running perfectly again.
Tech hands the boss a bill:
"Kicking the computer: $5000.00"

The boss goes nuts! "You CAN'T charge five thousand dollars just for kicking the thing!!!"

Tech says: "You're right." Tears up the bill and writes another.

"Kicking the computer: no charge.
KNOWING WHERE TO KICK: $5000.00"

[Low_Fi]

I located the service manual for the Performer here:

http://www.synthforum.nl/forums//attachment.php?attachmentid=40221&d=1221320648

On page 9 it shows the IC/eeprom with pin 7 designated for 'Sustain Line (All pins 7 are connected together)'. So if I'm reading the schematic correctly, each of the twelve sections on the board in the pic above handles one note in each octave and pin 7 on each IC within each section handles sustain for all notes in that section. The sections start with C on the left and proceed up the chromatic scale going right.

So I guess my issue may be with pin 7 on the leftmost IC or the connection somewhere leading up to it or after it?