[Hallicrafters] HT-33A Fan Assembly Needed

[Al Parker]

Hi Gary,
	Yup, you've got it.  I think some of the guys haven't realized that 
this tube is an external anode, finned, air cooled, tube similar in 
configuration, but bigger, to  a 4CX350 series, etc.  It requires a 
specific air flow to properly cool it, and that necessitates more 
pressure than what's required to cool glass 3-500's, 4-400's, etc.
	I had a "modified" HT-33 for several yrs, but sold it last yr due to 
acquiring a Henry 3-KA which replaced it.  You can see at 
<http://www.boatanchors.org/HT-33hb.htm>  I thought there might be a pic 
of the bottom, showing the fan, but guess not.  I do have a complete, 
nearly original, HT-33B that I can drag out & get pix or info if you 
need.  It's a future project, I do have one good tube for it.  There've 
been threads on the Halli & BA reflectors every so often abt those 
tubes, and the fact that most glass ones are gassy by now.  It's said 
that keeping filament voltage on them every month or 3 is helpful,it 
might be, but it won't restore a real flat one (experience).
73,
Al, W8UT
www.boatanchors.org
www.hammarlund.info



On 4/16/2010 3:53 PM, garyislander wrote:
> Thanks Al,
> Thats what it looks like to me.
> A large dia. fan with about 8-10 blades.
> It seems to be slightly larger in dia. than the tube and shroud.
> It mounts below the PL-172 tube socket.
> The case bottom vent plate is missing along with the fan assembly.
> This amp probably had problems years ago.
> But for free....I will try to salvage it if I can.
> Most likely worth the effort.
> Gary K1MQ
>
> ----- Original Message ----- From: "Al Parker" <anchor at ec.rr.com>
> To: "Halliqth" <hallicrafters at mailman.qth.net>
> Cc: "garyislander" <gary at garyislander.com>
> Sent: Friday, April 16, 2010 3:40 PM
> Subject: Re: [Hallicrafters] HT-33A Fan Assembly Needed
>
>
>> The HT-33 fan is 6 or more inches in dia., not just a small muffin fan.
>> It provides cooling air under some pressure to the tube, which is in a
>> shroud.
>> 73,
>> Al, W8UT
>>