Analogue-sequencer

Hmm its back again to haunt me so replacing the cable didnt fix it. 
I got drastic last night and swapped the display for a spare i 
bought just in case id need it in the future.
Its back to normal again..................for now. If it stays fixed 
do you think it may have been a faulty display or would you still 
suggest possibly a faulty connection somewhere still? I only ask 
becaus i might try to return the display to where i got it.

cheers
Brett

--- In analogue-sequencer@yahoogroups.com, "bambam4236" 
<hotbambam@...> wrote:
>
> 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
> >
>