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Old 21st Sep 2016, 9:25 pm   #208
Herald1360
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Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,536
Default Re: HMV 653 Broadcaster all wave.

If that's right it strongly suggests that more C is required across the LW oscillator coil to get the frequency down to 198+465=663kHz. If the gang's at about half way, it'll have about 250pF across the coil. If that's giving 928.5kHz, then L will be about 120uH. To get that down to 663kHz will need a total of 493pF, so about an extra 240pF. Making reasonable assumptions about strays suggests that the extra C should 220pF.

Hmmmm, 220.....22....?

Dodgy cap or old mistake? Who knows, but try 220pF and see!
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