Folks:
On 2/2/2015 2:36 PM, Bill Turini wrote:
I need a zener for my 2KD-3. It's a 1N4561. It appears that they are
really hard to find and exorbitantly expensive when you do. Has anyone
found a source for a replacement at a reasonable cost?
This request generated many wonderful replies and suggestions to fix my
problem. Last night I was RTFM when I noticed something very strange -
the zener diode I had removed from the amp was not the same as
identified in the schematic, and it was connected totally differently
from the schematic. Remembering the wise post from the Henry web site,
I decided not to trust my eyes or the schematic and asked the learned
group for their opinion.
First, the zener diode I removed from the amp was a 1N4561, a 5.6v 50
watt device. The schematic calls for a 1N2804, a 6.8v 50 watt device.
Since the removed device was not wired in any way close to the
schematic, I assume that this was an attempt at a repair or
"improvement". So, what should the voltage be? 5.6 or 6.8volts? Or
should it be something else? Since most of the other Henry 3-500z amps
have 10 volt zeners, I would vote for the higher voltage 6.8v device.
Second, as for the wiring in the amp, I think it is just wrong, since
all the other Henry GG amps have the cutoff circuitry the same. So, I'm
going with the schematic.
And, in case anyone is wondering, the 1N2804 costs just about the same
ridiculous price as the 1N4561, so I'll probably opt for the zener and
transistor route.
73's and thanks in advance.
Bill
--
Bill Turini
KA4GAV
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