[Johnson] 866 & 3B28 replacement

[Roy Morgan]

On Apr 21, 2008, at 9:38 AM, Chris wrote:

> Hello to the group
>
> Can someone tell me what the solid state Plug in is for the 866 &  
> 3B28 tubes?
> Is it the 1N2637???

I don't know what the designation is, but if you google for 1N2637  
you may get a good hint.  If you have solid state replacements and  
they fits the socket and top cap, use it.

  If I replace the 3B28 in my Valiant with the Solid State  
replacement do I have to do any thing to make them work correctly? I  
was thinking that it would Increase the HV

No. Do nothing.  It may increase the high voltage, but what's an  
extra 10 or 15 volts out of 1200 or so?

If you want to, you can remove the filament connections from the  
transformer to remove the high voltage from them and reduce the  
possibility of a short in the transformer.  (This is important in the  
Hallicrafters HT-32 and the like because that is a frequent failure  
of the known-to-be-weak transformer.)

Note: my experience is that the commonly found prices for the solid  
state devices are above what a pair of 3B28's cost.  So in terms of  
dollars, there is little to gain.  The 866's are failure prone, and  
the 3B28's are quite reliable and trouble free.

Roy


Roy Morgan
k1lky at earthlink.net
Lovettsville, VA 20180