[AMPS] Caveat on Dentron Filaments + MLA-2500B Notes

[measures]

>?  The MLA commits one of the worst layout errors known --too much
>distance between the anodes and the Tune-C
>
>You have got to be kidding! The distance is 5 inches...barely enough
>room to get all the Measures kits installed. Maybe the 2500 had problems,
>but the "B" model I have is super tame and easy to operate. The layout
>is no worse than a SB-220 IMHO, and has 160 meters to boot.
>
€  in an MLA, the tank coil is between the tubes and the Tune-C.  

>The other day you mentioned Alpha 77SX's using non-RF rated padding
>caps...I have had several SX's and repaired several. They all use RF rated
>door knob caps. 

€  RF rated caps come in two flavors, for use in tanks (-750ppm) , and 
for bypass use.  Bypass caps are not suitable for use in tuned circuits.  

> The trouble is that the 5 kw output is too much for the 160m
>load padders and they get hot and drift. 

€  ...  tank circulating current with two 8877s is about 20A.  The 160m 
padder cap that is used is rated at 1.4a max @1MHz. 

> Easily fixed by putting in larger
>door knobs, or several little ones, or going to micas. The Dentron MLA-2500
>uses the same RF rated door knobs as padders. @ 1500 watts, they all run 
>cool.

€  Not in the 77SX.  

>Another feature added to the MLA-2500B model is thermostatically controlled
>fan speed...nice touch. Also it uses a Radio Switch Co. model 78 band switch
>rated @ 20 amps.
>
>I think a lot of the initial 2500 problems could have been the stupid 
>suggestion
>in the manual to cut the swamping resistor loose if using a solid-state 
>exciter.

Amen.  ''Stupid is as stupid does''.  

later, Phil

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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