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Old 6th Jun 2011, 7:46 am   #46
sunthaiboy
Retired Dormant Member
 
Join Date: Jun 2011
Location: Crew Green, Powys, Wales, UK.
Posts: 68
Default Re: Test equipment for valve radio repair

Once one has obtained service sheets (or as a minimum cct diagrams) for "radios to be worked on" the most useful test equipment (in order of importance) must be a pair of DVM's (or a pair of 20,000 Ohms per volt Avo 8's if you want to stay period); both DVM's must have full complement of resistance, DC/AC current and voltage ranges (not all do).
An assortment of Insulated tips and probes for the above may seem a luxury, but aren't.
Measuring HT current and voltages (at the same time) is often key to fault finding on ill radios. A 250VA variac fed from a quality 500VA isolation transformer is a sensible safety precaution (for a small table top radio) for live working on a set that has not seen power for aeons. A 20Meg dual beam Oscilloscope (plus a pair of x1/x10 probes) is a very flexible tool and a good one can be picked up for less than £100.
If your radio for repair has been tweaked or fiddled with then a LF/HF signal generator may be required..... Spot wobulators are for the advanced or experienced engineer who knows all there is know about critical RF coupling and double humping.
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