wrote:

On Sat, 17 Apr 2004 01:24:02 -0400, starman wrote:

------- clip

The only componant(s) that would experience the higher voltage would be
the main voltage regulator which is apparently designed to handle an
input voltage of up to 15-V. The '800' actually has an internal DC to DC
converter which steps up the nominal 9-V input voltage to 15-V for
certain circuits that need a higher voltage. There must be something in
the owner's manual regarding the maximum input voltage.

Now you have me wondering if my Drake-SW8, which was the prototype for
the '800', could be run on 12-V instead of 9-V. I'll have to check the
manual and schematic.

A practical implication here is that if one desired to use the huge
S800 as a portable, a practical power supply might be a long, slim 12V
gell cell/SLA battery to fit in the battery compartment. Two 6V 1.3A
(3-3/4x2x1") gell cells will almost fit in there after removing the
receiver terminals. I'll experiment on playtime but suspect only
about 4-5 hours on the series gell cells. Otherwise, it's not that
difficult to saw a hole in the battery compartment and put a larger
gell cell in there.

Please check SW8 power and let us know if you think 12V may be
allright.

bball

You wouldn't have to use the battery compartment. There's enough room
inside the '800' case, on the speaker end, for a 12-V rechargeable
battery.

The SW8 manual says the power supply voltage should be in the range of
7-10 volts. I gave the schematic a cursory look. The nominal 9-V power
input doesn't seem to pass through a common voltage regulator before
branching out to other voltage regulators or unregulated circuits. If
this is the case, it would require installing a primary voltage
regulator so it could handle a 12-V input. That wouldn't be difficult
using a three pin IC regulator which was set to operate at 9-V but the
power loss in that regulator would decrease the operating time for an
external 12-V battery. I'll study the schematic some more to see what
the options may be. Someone said the '800' has writing on the rear of
the case that indicates it can handle up to 15-V input. I have a JPG
copy of the '800' schematic so I'll check it out too.


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