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Old 13th Nov 2007, 9:32 pm   #18
Andy Day
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Join Date: Aug 2005
Location: Hemel Hempstead, Hertfordshire, UK.
Posts: 154
Default Re: Test equipment for valve radio repair

Having come from a digital electronics background - way back fixing and modding ttl circuits, latterly switch mode supplies, monitors and laptops, I started driven by the need to search for a measurable fault on radios I worked on. In my naive fashion I assumed there would be "a fault" which when fixed would make the set burst into life. Poor fool!

The reality is that many components will have become leaky, changed in value or indeed in antiquity have been replaced with something unsuitable!

With this in mind, and as others have suggested, a blunderbuss approach is often more successful, and a simple dmm is the most useful tool in this, but NOT with caps! Firstly, mistrust all of these, especially Hunts and waxed paper, also most electrolytics, though you may be lucky with these. Then resistors, in many sets you will measure these and find the values all over the place, usually high. In spite of this they may not materially alter the operation of the set due to the tolerant operating parameters of hot bottles. If in doubt don't try to intellectualise the problem, change the component!

I've got all the kit apart from an FM sig genny. Mostly by a huge margin I use my £13 Dmm and AVO 8 I've had 37 years, but most useful is the Soldering Iron!
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