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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 2nd Apr 2012, 11:21 am   #21
BBRQ229
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Default Re: Eddystone EA12 - front end problem

David, my apologies for delay in response, but have been otherwise occupied and just thinking of having another go at this EA12 - which cost me a small fortune, only to be 'dead on arrival' - or nearly so. Keen to get it working therefore.

Will post progress or lack of it in a couple of days.
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Old 2nd Apr 2012, 8:11 pm   #22
Radio Wrangler
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Default Re: Eddystone EA12 - front end problem

Yeah, EA12s were sought-after radios in the 1960s and have matured nicely into sought-after collector's pieces with prices to match.

As has been said earlier, they were quite competently designed and worked well, provided you could get used to tuning across each band backwards. It's very well worth fixing, and shouldn't be too much bother. Faults are always simple when viewed in retrospect.

Eddystones have one nasty flaw. Their lovely low-geared smooth tuning is usually done with a thin shim disc gripped between sprung cones, giving very high reduction ratio in the first stage of gearing. Any wear in the tuning knob bush and a little movement of the axis of the shaft is equivalent to a significant amount of rotation. Any competent model engineer can make spares, but you need the right size reamer to finish it properly.

When you've got yours going, you might stir me into opening mine

David
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Old 7th Feb 2016, 2:26 pm   #23
Superhet Si
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Default Re: Eddystone EA12 - front end problem

Sorry to drag this up again but I have the same problem with my EA12.
It looks to me like the fault is in the RF amp (v1) although this valve is good.
The cathode of V1 connects to the muting circuit, so check the standby switch contacts and also the crystal switch. If I connect an aerial to pin 1 of the valve socket via a DC blocking cap I get reasonable performance.
Also checking c32 for a short.
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