[ARC5] Acceptable warmup time for SCR-274N, BC-455-A

[Kenneth G. Gordon]

On 16 Feb 2019 at 5:35, Dave Kirk via ARC5 wrote:

> I'm being told that the command set receivers are quite stable units. I must say the BC-454-E I 
> have is very stable after about 5-10 min or so. My BC-455-A on the other hand won't even start 
> to settle down till after an hour or more. So is this normal? I'm thinking not.

Many of the late Navy versions were especially "Stabilized". Those, as far as I know all 
blank-wrinkle painted, will have a yellow letter S surrounded by a yellow circle stamped on 
the front panel.

I do agree with you that your BC-455-A sounds most unusally unstable to me.

My BC-455s settle down within only a few mnutes after turn on.

I believe the small white dog-bone tubular ceramic capacitor which is soldered across two of 
the pins on the bottom of the socket of the 12K8 is a temperature compensating type. You 
might check to see if yours is still there, or is damaged some how. They are actually fairly 
fragile.

Ken W7EKB