Al,
I think
Graeme means the OC171 transistors in the RF and IF stages (the OC71 is in the
AF stage). The OC171’s have four leads, one of which is an earth
connection. These transistors tend to grow ‘whiskers’ in the can
that effectively short the transistor to earth. Chopping the earth wire of the
faulty transistor can effect a cure.
73’s
Gerry, G8GUH
From:
Sent: February 11, 2007 9:32 AM
To:
Subject: Re:
[eddystone_radio_users] EC10 Mk. II
Hello Al / G8DLH,
Assuming that the IF is properly aligned,
the most likely problem will lie with one of the OC71 transistors. These
have now become very dated (ie about 40 years old) and are known to develop
internal 'whiskers' which can short to the can, (which is earthed) or other
electrodes. Determine which stage has lost most gain (using sig gen with
calibrated output) and then snip the earth wire to that stage. It may
work. If not, I believe 'new' transistors are available from Birketts in
Good Luck, Graeme G3GGL
----- Original Message -----
From: Alan Ainslie
Sent: Sunday, February 11, 2007 3:45 PM
Subject: Re: [eddystone_radio_
users] EC10 Mk. II
EC10 Mk2 service info is available for download on the excellent EUG web site
Alan
----- Original Message -----
From: g8dlh
Sent: Sunday, February 11, 2007 2:14 PM
Subject: [eddystone_radio_
users] EC10 Mk. II
EC10 Mk. II seems rather insensitive on all bands: any suggestions,
please? A circuit diagram would also help: and suggestions, please?
Al / G8DLH
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