[sdiy] ENSONIQ keyboard woes

[Nathan M. Reeves]

yes it seems like a long shot for the diode check.....

i remember the korg polysix thing vaguely....

fortunately my DMM has a diode/continuity check built into it

its says to:

1. Remove all power from the circuit under test and discharge all caps.
2. Set to proper selection on switch, looks like a little diode icon.
3. Connect test leads to device you want to check.
4. Reverse test leads and note second reading.

If one reading shows a value and the other is over-range (0.F appears)  
the device is good.  If 0.F appears during both readings, the device  
is open. If both values are very small or zero, the device is shorted.

I did this and got 0.F for both readings.... though I am not sure if  
the diode I was testing had the key pressed (maybe i will tape all  
keys down while i do this...)

Tom Wiltshire says

"You can buzz them through with a multimeter continuity checker,  
assuming it uses enough voltage to overcome the diode drop. Sometimes  
they don't. This is why

they also include a "diode test" setting on the multimeter. Still,  
I've found it easier with an audible clue.

I tested a Polysix keyboard by taking it out of the instrument and  
lying it down upside down. This meant I could get to the PCB and  
connector, but more importantly

meant all the keys were pressed down so I could test the diodes. To  
avoid the multimeter problem I just mentioned, I tested it with a 9V  
battery and a buzzer."

what type of buzzer, just one from a PC will do?  i have PLENTY of  
those lol

so it looks like if its not the diodes, keyboard contacts, nor the  
ribbon connector than its most likely the MCU

i rather not pull the other MCU i have out of the working one.....

Are these obscure and rare  (read expensive) to find?

8^(

how do you check the ribbon cable for continuity?

What ended up being the problem with your Polysix Tom?  Did you  
resolve it?

How do I read through the archives again? 08^)

Cheers,

Nate