Chris's SR and all SR's

To the Group:
As I promised, here is what we found out on Chris's SR. We have a bug
in the diversity circuit and it is one of the "Awww crap!" bugs. The
circuitry is switching the wrong antenna input and not giving the full
signal improvement to the actual channel that is in trouble. Instead
of a correct 180 degree antenna phase change, the antenna combiner is
giving a much smaller change just because the antennas are a little
coupled. The small change helps enough that the unit can pass QC walk
tests. It is not nearly as good as it should be. With the firmware bug
corrected the units are comparable to the 401's, just like the
prototypes and beta units were. This fix will require new firmware to
be loaded into the unit. The new firmware is 1.6 or higher.

The lower RF readings will also be addressed in firmware so that the
UCR411's and the SR will read the same with the same RF input. Again,
this requires loading in new firmware. The low RF readings also tend
to make the diversity circuit try test switches more often and this
would make the above antenna bug worse.

The low battery indicator reading for CH2 in Chris's unit was due to
350 kHz IF bleed through getting into the microprocessor A to D port.
We will add a 1 uF capacitor to the CH2 window detector output to
eliminate the bleed and also add one to CH1 as a belt and suspenders
fix. This will be a no charge service update performed on any unit
that comes to the factory for service at any time whether needed or
not.

We didn't find any reason for the touch sensitivity of Chris's unit.
After he gets it back and in his system, we can see if it still does
it.

The pleasant stuff in this 1.6 firmware change is that we will also do
two more things that users have requested:

1. Add ability to read external battery voltage. A brief push of the
power button will read the voltage at the power jack.

2. Add ability to control backlight behavior as "always on", "always
off", a "30 second timeout", or a "5 minute timeout" . This will be a
deeper menu selection and the normal user will only need to access it
once (i.e., never have to open the manual again) to set their
preferences.

Since there are hardware changes involved, this update and bug fix
will need to be done at the Lectro mothership. We will pay UPS blue
label (two day) freight both ways and do the mods at no charge, of
course. If you can't get around to it soon, we will take care of it
whenever the units show up. Always call service (800 821-1121) for a
Return Authorization. It is not required but makes all our lives
easier.

Sorry about this,
Best Regards,
Larry Fisher
Lectrosonics


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