Patches and discussion for Ensoniq VFX family

Hi,

Problem: 

A. keyboard going out of tune, both on internal sounds AND when I 
use the SD to act as a controller, it detunes the sound module as 
well.

B. I notice that when im in a page that has parameters (master, Midi 
etc...) the values for the underlined value change by them selves .

Referring to Service Bulletin 12 
I took it all apart and found:

1. Eprom KPC 2.32 520c  
2. Foamless keyboard with reference coil
3. 20 pin connector between the two boards
4. the 20 pins are joined by two small ribbon cables all soldered.


Heres what i did so far:
1. Opened keyboard top cover, removed the 10 screws from the bottom 
of the keyboard, removed the keyboard assy, also removed the 
floppy/pitch/mod wheel cover to get access.

2. Using a continuity tester, I tested each pin on the 20 pin 
wiring, side to side, I had continuity

3. disassembled pitch bend and mod wheel sliders and sprayed out the 
pots with contact cleaner.

4. Lithium battery- put a volt meter on it and it read 3.20 volts
5. detached display and button circuit board (the one under the 
display) and cleaned out the volume and data slider pots with 
contact cleaner


Problems I encountered:

1. When removing the display circuit board, I had to take off the 
volume and data slider covers, when I did, the volume slider bar 
came out of the assembly, cant seem to get it back in. Do I need to 
replace the whole slider or can i get the metal tab back in?

2. When checking the battery, I noticed that the metal tabs that the 
battery attaches to the board can be "rocked" (moved a bit from side 
to side.  Could the solder connection be intermittent and causing 
the problem? Can the tabs be soldered with out removing that main 
board? (this is the board that has all the inputs on it, and I would 
have to unscrew all the inputs to get it out)


Im going to reassemble it now and test. If any of you have 
suggestions PLEASE help !!! :))

Thanks to Richard at Route 66 studios for the service bulletin, 
advice, AND the courage to do this job myself !!!

Rich G
Freehold NJ

PS, I have a gig coming up on Saturday, and need to fix this or get 
another keyboard, if any of you are in NJ, please contact me if you 
can loan me a board, or if you have something inexpensive to sell 
that can do brass, strings, organ etc...:)