Analogue-sequencer

> I have just been using my P3 again and noticed some very weird 
> behaviour from the display...the sequencer appeared to function as 
> normal though. Some of the things i saw were :

The display module is a little computer in its own right.
Weirdness of the sort you describe is usually caused by errors in the data
transfer from the main P3 CPU to the module CPU.
I've seen this happen with ribbon cables where there was a poor connection
on one of the data lines - fixed by replacing the ribbon cable.
Also make sure your ribbon cable isn't excessively long.

One other cause of this problem seen in earlier revision P3s is the
transistor used to drive the display ENABLE line.
In a couple of cases, the gain of the transistor used was below spec, and
the signal therefore wasn't fast enough to work reliably.
This only applies to boards before revision 1.6.
The transistor in question is Q1 - you can improve the performance by
driving it harder - change R20 from 22k to 10k.
Or just put in a transistor with better hfe.

Best regards,
Colin Fraser
Sequentix Music Systems Ltd
http://www.sequentix.com