Philco 680 Shadograph. - Printable Version

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+--- Thread: Philco 680 Shadograph. (/showthread.php?tid=17883)

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Philco 680 Shadograph. - vaguy22 - 02-02-2018

Has anyone fixed a Model 680  shadowgraph. I tried the usual hints from the " repair bench" with no results. the vane is free and coil shows 500 ohms resistance. #85 tube is good with 70 volts plate voltage. Thanks in advance   Norman

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RE: Philco 680 Shadograph. - Nathan Slingerland - 02-02-2018

Any chance that the bar magnet has become demagnetized?

500 ohms sounds low to me for the coil resistance - typically they're >1K.

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RE: Philco 680 Shadograph. - morzh - 02-02-2018

Even if 500 ohm, still should react.
I second the magnet thought.

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RE: Philco 680 Shadograph. - Radioroslyn - 02-03-2018

Just for grins take a 9v battery - to the chassis and + to the grid cap of the 85. Should cause the vane to deflect.

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RE: Philco 680 Shadograph. - vaguy22 - 02-06-2018

Thank you folks for the hints. Norman

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