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Philco 89 (123) (Update-Coil rewind)
#5

I forgot to mention: A properly restored, stock 89 can work just about as well as one does with the "Super 89" mod - IF you take the time to bake the oscillator coil in your oven for about 30 minutes at 200 degrees F, then clean off and rewind the outer (tickler) winding. This is critical. These oscillator coils are very prone to moisture absorption. Also, be sure you replace the 15K resistor in series with the oscillator coil tickler winding - part (10) in Bulletin 146 - with a 10K or even 8.2K unit; 1/2 watt is fine. In addition, you must replace the capacitor in parallel with this resistor, part (8) in Bulletin 146, with a new 680 pF mica or NP0 ceramic cap. The original was 700 pF and is a paper-wound cap inside a bakelite block shared with a .09 uF cap connected as a B+ bypass. 680 pF works fine as a replacement for the 700 pF cap. This will cure most, if not all, of the ills associated with Model 89.

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Ron Ramirez
Ferdinand IN


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