Hi
Few days ago I bought a (circa year 1980) Henry Radio
Tempo 2002, 144 MHz 2 x 8874 amplifier. There sure are
risks involved but the price was right.
I was astonished to find out that the blower takes the
air inside the cabinet _and_ the hot air from the tubes goes
inside the cabinet. At least it seems to be so; this far I
have only removed the top cover for inspection - did not
see what is in the "basement". The pictures in the manual
did not help much.
The amplifier seems to run quite hot for my taste. On the
other hand there are no signs of running too hot; no molten
or barbecued parts inside and no "smell of radio".
My intention is to mount a huge fan to the meshed
top cover in order to improve the air flow. Now there
is only natural convection from the cabinet to ambient.
Does anybody know if the centrifugal blower cooling
the tubes is powerful enough? What pressure difference
it is capable of producing (in that particular assembly)?
Especially with European 50 Hz AC ?! In other words
what is the maximum tube dissipation with that blower?
Is there PCB in the oil-filled capacitors? (By the way
the original owner had the amplifier ordered for 50 Hz so
the resonant choke in the power supply should be on the
right frequency)
73
Ilkka OH3NJC
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