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Old 12-30-2013, 02:39 PM
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rickfray rickfray is offline
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Predicta Holiday Contrast pot (VR1) mod

I'm doing my final lookover on solder connections and am redoing the wirewrapping at various locations on my Predicta Holiday. On the contrast pot (VR1), I noticed, unless I labeled my wires wrong as they attach to the binding posts on the Oscillator circuit board, is that the ends seem to be flipped. Terminal 1 which connects to a 1M resistor (R2 on the Philco schematic) then connects to Lug 1 (my notes) but the schematic says it should be Lug 16. Terminal 3 connects directly to Lug 16 (my notes) instead of Lug 1 in the schematic. Did I perhaps mistake the labeling? Re-looking at where the wires come up thru the chassis, they appear to located nearest the logically closer lug (1 or 16), otherwise they have to cross-over to connect as the schematic has it. Does this matter or is it just the case that the contrast would just change in the opposite direction as expected? I haven't found anything else that doesn't match the schematic yet so want to make sure it's wired correctly before putting back together. Thanks

Rick
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Old 12-30-2013, 05:25 PM
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bandersen bandersen is offline
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My holiday has the wire (blue) from the 1Meg resistor going to L1 same as yours.

I'm also currently working on a Predicta Tandem with the very similar 9L38 chassis. It has the 1M resistor going to L1 on both on the schematic and the actual wiring.
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