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Newbie Model 71 questions
#3

Hi and Welcome to the Phorum,

>Are there any critical wire lengths that I shouldn’t alter as I clean up and rewire?

Generally speaking wiring should be neat, close to the chassis when possible and not excessively long. Wiring that can create problems are if heater wiring is near control grid wiring (can induce 60cy hum) and if control grid wiring is near plate wiring (can induce unwanted feedback).

>Part  (21) Filter Condenser Bank ( 2x0.05u, 1x0.25u)  04731 appears to be missing. Three caps numbered (21) appear on the schematic but I don’t know which of them is the 0.25u.

On #21 the .25mf should be connected to the center tap of the power transformer's hv winding. The .25 may have been replaced by a small electrolytic like 10 or 20mf @35v + side to the chassis and - to the ct.

>Part (38) 3903AA  and line filter caps (49) are also missing also missing but I can work around those.

OK

>The tone control (39) appears to have an integrated cap but the schematic shows no value. Any suggestions?

Value is not very critical it just determines how much high frequency response it cuts off. Larger the cap the less highs you will hear. Typically a .01 or .02mf  at a 630v or higher voltage.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry


Messages In This Thread
Newbie Model 71 questions - by gmg - 03-13-2017, 07:43 AM
RE: Newbie Model 71 questions - by TV MAN - 03-13-2017, 02:37 PM
RE: Newbie Model 71 questions - by Radioroslyn - 03-13-2017, 03:42 PM



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