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Old 21st Feb 2017, 10:30 pm   #1
Colin Ames
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Default Sky Casket output transformer resistance

Last year, while back home in the UK for a holiday, I treated myself to an Ever Ready Sky Casket. I have just put it on the bench, and have found that all four valves are dud. Three have open filaments, and the fourth has very low emissions. Anyway, before looking for a set of valves I thought it would be a good idea to verify that the output transformer is OK. I disconnected one lead from primary and secondary, and checked DC resistances. Primary is around 550 ohms, and secondary is 0.7. Could anyone tell me if these are reasonable values?

Thanks in advance for the help.

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Colin
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Old 21st Feb 2017, 10:34 pm   #2
HamishBoxer
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Default Re: Sky Casket output transformer resistance

They sound ok to me.
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Old 21st Feb 2017, 10:34 pm   #3
Cobaltblue
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Default Re: Sky Casket output transformer resistance

The DC resistance of the output transformer sounds correct.

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Old 21st Feb 2017, 10:40 pm   #4
Herald1360
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Default Re: Sky Casket output transformer resistance

Sounds reasonable. Another check would be to reconnect speaker to secondary, connect a 1k resistor across the primary then dab a 9V battery across the primary. This should give some good crackling noises from the speaker.

The 1k will limit inductive kick back voltages to a safe level for the TX insulation.
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Old 22nd Feb 2017, 12:39 am   #5
Colin Ames
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Default Re: Sky Casket output transformer resistance

Thanks you all for the prompt replies. I now feel confident about searching for a set of valves.

Regards,

Colin
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