[ARC5] Fw: Oscillation at high gain

[Roy Morgan]

At 08:40 AM 3/3/02 -0700, you wrote:
....When I turn
>the gain up it goes into oscillations. ...Any clues?


Bad bypass caps.
Poor grounds.
Grundgy connections at the base of IF cans (especially the ground connection)

Note:
Metal tubes usually have the metal case and/or internal shield connected to 
pin 1. If the ground to that pin is broken or bad from corrosion at the 
grounding stud, the thing will act like a capacitor to couple oscillating 
energy.

This situation befuddles some table radio repairers when they try to put a 
metal tube in the place of a former glass one that had a metal shield.  The 
socket pin may be missing (for manufacturing economy) and so the set 
oscillates like crazy.

Roy


- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
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