Mathew Quaife wrote:
> Ok, I took the cover off, there are no tubes inside this unit at all. As
> for numbers, if it was there, they are gone. This radio has been sitting
> around for ever in a garage, so hard to say what happened to the numbers.
> Numbers that I see inside this unit are TFD6000A, TLD6812A-5, TLN8387A, and
> then the one Stamped on the Top TGN6002A. Inside the PA aera, there are two
> transistors that feed to the bottom for the heatsink. Can't see any numbers
> on them. Several tunning pots, and coils. The control head, I am told said
> Motran on it. Tis all that I know about it. Thanks.
>
> Mathew
>
I'll state this in a way others didn't: If it has heatsinks on the
sides, there are two tubes under the big heat sink in the back!
And even many of them that don't have the heat sinks on the sides still
have tubes. The heat sinks on the sides are power supply transistors,
not finals!
Take off heat sink on the back and it'll be obvious!
And there is no such thing as a 'solid-state tube'! That's an oxymoron.
Also there are two main types of VHF receivers. The 'H' series (model
numbers would be like U43HHT. The first H is receiver type.) has an
oven-type crystal, and the first RF amp is bipolar (or did it even have
one...?). The 'L' and 'M' series had a mos-fet RF amp, and used channel
elements. Also had a big cast helical resonator assembly, so it had
better out-of-band rejection.
HHT series radios are junk, and can be sent to the scrap heap. Not worth
getting crystals for.
The LHT and MHT series had decent receivers, but were a bit difficult to
interface COS, plus needed some funny voltages (8 volts I think?)
The transmitters might be OK for a while, but you'll go bankrupt getting
new tubes for it. A customer where I used to work had a lowband Motrac
base that needed tubes. I priced them out at the time (around 1994-5)
and found it would cost us nearly $1000 for the two tubes. You might
find used ones cheaper, but...they're used.
--
Jim Barbour
WD8CHL
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