Analogue-sequencer

Hi colin

i have a newer one so i dont think its the transistor and after 
playing around with it a bit more and double checking and recrimping 
the cable it appears to work fine...if it returns ill try a new 
cable.
Thanks again for the info and hope you enjoyed your trip.

Brett

--- In analogue-sequencer@yahoogroups.com, "Colin Fraser" 
<colin@...> wrote:
>
>  
> > 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
>