> as for the gate signals in a100,are
> you sure that the gate signals are from 0volts to
> 12volts i thought that they were from 0volts to
> +5volts...anyway if you are right,then your theory
> explains the problem with the a150/151 and clock
> signals...

Yes, I'm sure, I checked them last night. Of the modules I have the
clock pulses from the 160/161 are among the largest output by any
module, and are 0 - 12V. The digital noise from the 117 is also 0 -
12V; the gate signals from the 119 and 191 are also quite big, at 0 -
9V. I don't have a 151, but my 150, even when off, will basically
output a 0 - 8V pulse with a 0 - 12V pulse as input - the size of this
pulse decreases as the size of the input pulse decreases, until the
switch behaves properly when the input is down to 8V. I don't fully
understand the mechanism by which this happens yet, but I suspect its
the 4053 chip rather than the circuitry. Its behaviour is dependent on
the direction through the switch and also whether the unused I/Ox
socket is grounded or not. I suspect the curcuitry in the 151 is
similar, and thus probably suffers similar problems.

> thank you for your valuable info,.you seem to know a
> lot about the a100!

I don't know about this, but I'm having loads of fun working out what
makes everything tick!

[The views expressed above are entirely those of the writer and do not
represent the views, policy or understanding of any other person or
official body.]