[Elecraft] Possible Info 080 problem v2

[Jay Hanawalt]

Nickolas-

The 16C72 has an absolute voltage limit of 7.5V and is rated for 4.0V to
6.0V operation. Not trusting the tolerance on a 78L06 (specs are
5.8-6.2V) I substituted a 5 volt ZMR500 (a lower quiescent current
device, but a 78L05 should work) regulator with a 1N4148 diode, bypassed
with a small cap, in series with the ground lead that gives me about
5.5V to the I/O chip.
 
Wayne admonished me to carefully check to operation of all the relays
connected to the chip as this can reduce the amount of coil drive
available from each output pin. So far everything works fine.

I have also used this same scheme with all the 78L06 regulators on all
the option boards. There are some where this would affect firmware
calibration tables, Wayne warned me, but so far I have not found any
problems.

If you should try this your results may not be the same, but I thought
this might be helpful if you like to experiment and "improve" on things.

(My "improvements" are not limited to radio. My shack is a perfectly
good small folding travel trailer that I shamelessly attacked with a
saber saw and other tools to add a large inverter, battery bank, shower,
and air conditioning, among other things the manufacturer never planned
on. Gives good Field Day.)

-Jay, WB6SZE
 K2 #2322


Nicholas Lokuciewski wrote:
 
> P.S.: I am suprised that the IOC chip is being supplied with 6V (via
> regulator), I thought it would be 5V? (But it says it on the schematic)