[Boatanchors] Lettine 240 Transmitter Plug In Coils

[LEE BAHR]

So Carl, does this mean you were the crazy one who wired this puppy up?  (I 
hope you have improved your wiring skills since then).  I now know why they 
used galvanized steel chassis as they could solder a ground connection 
anywhere.  Tie points?  Who needs tie points!  It looks like maybe they used 
a gutter company to manufacture their chassis.

Do you know who owned Lettine?  Maybe you could give some insight regarding 
the company and what is was like working there.  Or maybe you don't want to 
relive that part of your life.  (Might bring up nightmares).

Lee, w0vt


----- Original Message ----- 
From: "Carl" <km1h at jeremy.mv.com>
To: "LEE BAHR" <pulsarxp at embarqmail.com>; <boatanchors at mailman.qth.net>
Sent: Tuesday, December 14, 2010 2:49 PM
Subject: Re: [Boatanchors] Lettine 240 Transmitter Plug In Coils


> Ah, the infamous Latrine 240. I spent many afternoon and weekend hours as 
> a HS student helping to assemble those TVI generators for a most nasty and 
> ungrateful pair of owners. At least they were in my home town and I could 
> ride the bike there in about 15 minutes. I quit after about 3 months and 
> positively burnt the bridges behind me!
>
> Carl
> KM1H
>
>
>
>
> ----- Original Message ----- 
> From: "LEE BAHR" <pulsarxp at embarqmail.com>
> To: <boatanchors at mailman.qth.net>
> Sent: Tuesday, December 14, 2010 2:15 PM
> Subject: Re: [Boatanchors] Lettine 240 Transmitter Plug In Coils
>
>
>> As I mentioned earlier, the Lettine is a rats nest under the chassis.
>> Everything needs to be replaced including the AC line cord.  The 
>> transmitter
>> was modified to include a changeover relay which is also in a rats nest
>> fashion plus much of the cloth wiring looks like it could stand 
>> replacing.
>> Combine this with the fact many of the tie points have no lugs but are 
>> just
>> "free in the clear floating connections", I decided I will "strip the
>> chassis down and start over.
>>
>> I ordered all new caps and resistors plus a 3 prong power cord yesterday
>> from Mouser for the re-construction.  Lettine placed some of the parts in
>> some really strange places.  Because of this,  I am not sure I want to
>> remove everything at once and then start over or just replace everything
>> section by section.  I am inclined to do it the later way as the wierd 
>> parts
>> placement at times plus the lack of tie lugs, which I plan to add, lead 
>> me
>> to believe I can keep parts placement closer to original specs if I do it
>> section by section.  I'll probably start with the power supply and then 
>> move
>> on to the oscillator and then to the final.  Once the RF is working, 
>> I'll
>> move on the to audio input and modulator stages.  The only problem doing 
>> the
>> restoration this way is it is going to be harder replacing point to point
>> wiring.  (I think I need to take a few pictures of it as it now stands in
>> case I run into trouble.  I am a little nervous of using the BAMA manual 
>> as
>> it was "re-drawn".  (I already found three small mistakes in the BAMA
>> re-drawn schematic).
>>
>> When ordering the new parts,  I ordered much larger wattage resistors 
>> then
>> the originals to make the new parts closer in size to the originals as 
>> many
>> new parts of the same wattage are much smaller today.  Instead of 8 mfd
>> filtering I will have 16 mfd of power supply filtering.
>>
>> The plate choke and parasitic supressor as original are a real joke.  I 
>> am
>> seriously thinking of putting in a real multi-pi RF choke feeding the 807
>> plate and also put in a more standard parasitic supressor on the plate 
>> lead.
>>
>> As it stands, this is a real complicated restoration when you consider 
>> this
>> is a simple transmitter with not too many parts.  The unorthodox layout, 
>> bad
>> wiring job, lack of tie points and rotted wires all make the restoration
>> difficult more difficult.  Once restored, the bottom chassis will look 
>> very
>> unencumbered and look like it was a piece of cake to restore.
>>
>> Then, comes the restoration of a plug in coil set for this transmitter.
>> This is a "cool" kind of rare transmitter.  If it were not for it's great
>> outside appearance, the time spent restoring this transmitter could not 
>> be
>> justified.  When finished it will be a jewel, but you could never get 
>> your
>> time and money out of it if you ever would want to part with it.  I know
>> this going into the restoration.  As I mentioned earlier,  a WRL Globe 
>> Scout
>> 40A looks like a Collins internally compared to this rigs guts.  The 
>> Lettine
>> cabinet, front panel and transformers were all first class.  From that 
>> point
>> on it was all downhill.
>>
>> Lee, w0vt
>>
>>
>>
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