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Old 22nd Dec 2017, 9:59 am   #17
ms660
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Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Advance E2 Signal Generator repair

With luck the RF generator should be ok on all ranges, best to check the VHF range with a radio as your 'scopes response will have dropped off like a stone much above 20MHz, at VHF frequencies it will be non existant.

For no modulation I would first check the AF output, if no go then check the mod switch and valve contacts and the tuning capacitor across the AF inductor, that capacitor is known to have failed in the past so I would replace it and the other one (C12 & C13) and take it from there.

EDIT: To see any AF modulation on the scope properly its best to reduce the 'scopes timebase speed so that one or two cycles of the modulation frequency can be displayed.

Lawrence.

Last edited by ms660; 22nd Dec 2017 at 10:25 am.
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