Hello Gary,
My 77D(x) has a rheostat in the blower supply. I'm not sure if that was
the same for all. Since mine is an early model it also has a thermostat
switch mounted on the exhaust plenum that shorts out this resistor. I
believe that was later deleted. I have the blower set quiet slow with
the rheostat but the air out the back never seems to get too hot and the
thermostat has never switched to high speed but then I don't tend to use
it for high duty cycle modes.
My blower is quite noisy, definitely worn bearings and I plan to replace
them in the next few weeks. If that proves successful maybe I can run
the blower a bit harder without needing ear defenders.
Whilst some might argue the original 77 transformer was a bit weedy and
the tank circuit somewhat undersized in some situations (2 tubes on
160m) the blower by comparison seems almost excessive in the 77, almost
able to achieve that desired state of being able to lift the tube from
its socket :) This on a 50Hz supply where a lot of blowers are
distinctly under sized.
73, Martin, HS0ZED
On 23/10/2017 18:35, Gary Smith wrote:
Not sure why my message didn't send
properly but I'd sent:
Got it. Thanks for the direct replies.
I am finally getting around to adding a
thermostat to the amp to allow slower fan
rotation at idle and full rotation when
transmitting. The blower on this thing is
a beast.
73,
Gary
KA1J
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|