[Amps] Fwd: rx noise?

[Ian White GM3SEK]

David Robbins K1TTT wrote:
>I think the noise in that one is solved... take a look at the scope pic 
>for a 12v regulator with a 2v p-p oscillation on it at: 
>http://wiki.k1ttt.net/2008%20Maintenance%20and%20Upgrade%20Blog.ashx?NoR
>edir ect=1#Bottom That's one repaired, another one tested clean for 
>now, and 5 more to go.
>
Glad you found the problem, Dave. By coincidence(?) someone recently 
found a similar problem with a 78xx in a GaAsFET preamp that had been OK 
for years, but then decided to become unstable.

Any thoughts about what changed to trigger the instability? (Aside from 
it being CQWW weekend, and the regulator having poor stability margins.)


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek