TX-1 Temp Test Results (Was: AC Line Voltages, Then and Now)

[Mike]

The Apache TX-1 will run warm in AM mode. The HV transformer will get warm
during use. If the TX-1 is not put in transmit, the HV transformer should
not be very warm. Any heat a non-transmitting TX-1's HV transformer has is
conducted from surrounding transformers. The HV transformer primaries only
has voltage on it in transmit. In standby, the primary voltage is removed,
no HV on the final amplifier tubes. However, during a round table QSO, the
TX-1 will get very warm and that's why it needs allot of cooling.

My suggestion is to have good air flow around the transmitter. The only
cooling vents are on the top and bottom of the case. The rear and sides are
closed, no air vents. If you find a Marauder case, the TX-1 will fit in
that case. The Marauder has top, bottom and rear vents allowing more air to
flow around inside the TX-1 keeping it cooler. However, the final amp fan
should be checked and, if necessary, cleaned and lubricated. This fan over
time will slow down causing the cooling to be reduced. I don't like the fan
motor in the Apache, it's too slow and, with age, it's more likely to have
reduce air flow. A good replacement is a 120VAC muffin type fan which has
much more air flow than the original fan. I have a Marauder HX-10 and its
original fan was just like the Apache, a phonograph style motor. I took it
out, threw it in the trash and installed a 120VAC muffin style fan. The top
of the final cage is much cooler along with the rest of the transmitter.
I'm sure this can also be done with the Apache.

There is insufficient room inside the final cage of the Apache to install a
muffin style fan inside. To change the fan to a muffin style, the top cover
of the final cage has to be replaced with perforated aluminum and the
muffin style fan attached ontop using new screws to the aluminum. By the
way, the muffin style fan is much quieter than the original fan you would
hardly know it's running after it starts. The original TX-1 fan makes
noise, vibrates and takes a bit longer to quiet down.


73's,

Mike
W5RKL




On Wed, 10 May 2006 20:42:10 -0700, digital-conjurers at ADELPHIA.NET wrote:

>Thought the group might be interested...
>
>Well, I first ran the TX-1 for an hour at 115VAC, transmitted a bit (AM),
then checked the temp of the transformers:
>
>Power Transformer: 37C
>Modulation Transformer: 35C
>Plate Transformer: 30C
>
>Then I kicked it up to 123VAC, and tested it after another hour:
>
>Power Transformer: 47C
>Modulation Transformer: 43C
>Plate Transformer: 38C
>
>...and then came the surprise.  I ran it back down to 115 VAC, let it sit
for another hour, then measured:
>
>Power Transformer: 49C
>Modulation Transformer: 46C
>Plate Transformer: 40C
>
>Whoa.
>
>...so it seems that the running temp of this unit is more a function of
time, rather than AC input voltage.  At the least,  the extra 8 volts AC
input voltage doesn't seem to matter a great deal here.
>
>With anything (like some 30's broadcast sets) designed for 110VAC running
on 127VAC, yes, I can see that shortening tube life and heating it up a
bit, especially with any radio that, by design, ran final audio tube plates
at the ragged end of their ratings with a 110 VAC input (Atwater Kents come
to mind.... )
>
>But with this 1958 Ham rig, it doesn't seem to matter _too_ much.
>
>Just an informal, non-scientific test.  :)  Thanks to all who responded,
this is a great group.
>
>Lin/KJ6EF
>
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