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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 14th Apr 2017, 11:28 pm   #1
Wendymott
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Default Eddystone EC10

Hi peeps...... a bit of a "head scratcher"..
I decided to put my EC10 Mk 2 onto the market... thus I needed to check it was ok before sale.
No RF oscillation on Bands 4 & 5.... I.e Top band and M/W.
As this radio was kept as "NOT MODIFIED" as a reference, all the usual germanium stuff was untouched, thus I replaced the Carbon Comp resistors in the bias circuit, all were within spec, but replaced anyway.
As I had already modified an older MK1 with a Silicon BF970 and changed the bias resistors to suit, that worked ok.
However.... doing the same mod on the MK2.. the Band 1 Range.. 18 - 30Mhz.. No Local Oscillator at any part of the tuning range.
I have tweeked the bias,,,, reduced and increased the feedback resistor...still no RF
Is there something that the OC117 has that the BF970 has not.... such as more inter junction capacitance.....
Your help would be greatly appreciated
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Old 15th Apr 2017, 3:08 pm   #2
Wendymott
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Default Re: Eddystone EC10

Sorted.... no need for any comments.Scope probe loading........ runs ok with a sniffer loop.. Amazing what a nights sleep can do...Dohhhhhh.
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