tubes age 83
----------------------------------------------------------------------------------------------------------
Date: Mon, 7 Jan 2002 15:45:02 -0800 (PST)
Subject: RE: [R-390] 6080 in place of 6802 ....
R-390 people, 6080's can be used in place of 6082's in the R-390 (NON A), if
you series the filament for both tubes....OR you could put a single Diode in
series with the filaments if you have no aversion to "sand state" devices in your
R-390 (NON A)
-----------------------------------------------------------------------------------------------------
Date: Mon, 7 Jan 2002 16:08:29 -0800 (PST)
Subject: Re: [R-390] 6802 - and heat dissipation...
The reason that the 6082's are HOT is that they are dropping the input voltage
to 285v x the current consumed by the R-390. Therefore power dissipated is
(325 - 285) * .3A = 12Watts. This amount of heat would have to be dissipated in
the "solid state regulator" anyway. I agree that the heat from 4 filaments would
not be introduced into the receiver with a solid state regulator.Remember that
when the R-390 is in "standby" there is no current being drawn from the HT, so
the input voltage would rise to approx 360v+, that is 75v across the "collector -
emitter" a big ask for a Transistor, then again Power MOSFET could be used ....
PS: Just think of the ZENER chain to get 285v for the "series regulator" !!!
Then again you could use tubes for that!
------------------------------------------------------------------------------------------------------
Date: Mon, 7 Jan 2002 17:16:06 -0800 (PST)
Subject: Re: [R-390] 6802 - and heat dissipation...+ standby
Quite right, the HT is 185v, that is a lot of watts.... My understanding of "not
using standby" is the "poisoning" of the cathode, with filament current and no
HT to "pull away" the electrons. Note also how bright the "regulator" tubes glow
when in standby, NOT GOOD ! The Hallicrafters SX-101A has the VFO tube
fillament "ON" AND a "heater resistor" under the circuit at all time even when
the "power" switch is in the OFF position, they use a series resistor in the
filament to drop the heater current. Is there a message for us, in this circuit
design ????
----------------------------------------------------------------------------------------------------------
Date: Mon, 07 Jan 2002 20:40:17 -0600
Subject: Re: [R-390] 26Z5W - 12BW4 replacements
Has anyone actually done this? If so, how does it work?
------------------------------------------------------------------------------------------------------------
(14 pages)
(10 pages)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Commentaires sur ces manuels