Admiral 14R12 Restoration

[Kevin Kuehn]

Have you changed or tested the 1M resistor that's mounted under the 1B3 socket? Those often go very high in value/intermittent, or open. It's the 1M shown in series with the HV lead on the Sams schematic.

The boost voltage is derived by combining the 210 volt supply with the voltage of the lower flyback winding during horizontal retrace. It's a free source of energy during retrace, and so provides a boost to the 210 voltage supply that gets filtered and used for some circuits that work better with the higher voltage.

[Kevin Kuehn]

That was my oversimplified explanation of how boost voltage is generated. It's the best I can do while drinking Jack and Coke at 12:30am.

[Crist Rigott]

Originally Posted by Kevin Kuehn

Have you changed or tested the 1M resistor that's mounted under the 1B3 socket? Those often go very high in value/intermittent, or open. It's the 1M shown in series with the HV lead on the Sams schematic.

The boost voltage is derived by combining the 210 volt supply with the voltage of the lower flyback winding during horizontal retrace. It's a free source of energy during retrace, and so provides a boost to the 210 voltage supply that gets filtered and used for some circuits that work better with the higher voltage.

Kevin,
The the 1meg resistor was changed and still measures 1 meg.

Thanks for the explanation for boost voltage.