[Boatanchors] Millen High Voltage Connectors

[Bill Abate]

Dave,

I use the Millen HV connectors (red and black) for my HB amp.  I run 
4700 VDC on my 4-1000 with no problems (SSB not AM).  I did manage to 
blow one up during testing one day.  Developed a short somewhere and 
blew the HV fuse and the chassis HV connector went into pieces.  No 
problems since.  Just make sure you are meticulous in removing the flux 
after soldering to it.  I'd give it one more try.  Otherwise I've seen 
special HV BNC connectors for that application.  I can dig it out if you 
want.

73,

Bill

david knepper wrote:

> My homebrew transmitter,  designed by Stan, W3TGR now a silent key,  
> is going through exhaustive and often frustrating testing.  Stan used 
> lots of shielded wire - you know the Belden stuff that is 
> deteriorating over time with brittle insulation on the wire. I had to 
> replace several leads because the center conductor was shorting to 
> ground when the insulation became brittle.  So it goes ...
>
> Today, I thought that I had finally debugged the unit - pair of 813's 
> modulated by 805's - but I heard the troubling sound of high voltage 
> to ground.  Measuring the Millen connectors to ground revealed a 
> short.  Here the Millen connectors on the modulator were arcing to 
> ground on the secondary side of the modulation transformer running 
> from the high voltage through the secondary winding to the PA 
> amplifier.   I am using those light tan units that are supposed to be 
> better than the red connectors.  Stan used these connectors on the PA 
> amplifier, the modulator deck, and the high voltage power supply.
>
> I suppose that under modulation that the peaks exceeded the voltage 
> rating of the Millen connectors.  Once before many years ago, I had 
> the same problem.  However, these connectors are often used in 
> homebrew construction projects as described in the ARRL handbook.
>
> Any ideas out there other than to go with ceramic feedthrough insulators.
>
> Perhaps, it is because of their age and the insulation is breaking 
> down. Who knows!
>
> Thanks
>
> Dave, W3ST
> Publisher of the Collins Journal
> Secretary to the Collins Radio Association
> www.collinsra.com - the CRA Website
> Now with PayPal
> CRA Nets: 3805 Khz every Monday at 8 PM EST
> and 14255 every Saturday at 12 Noon EST
>
> _______________________________________________
> Boatanchors mailing list
> Boatanchors at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/boatanchors
> ** List Administrator - Duane Fischer, W8DBF/W9WZE **   ** For 
> Assistance: dfischer at usol.com **         $$ For vintage radio info, 
> see the HCI web site $$      http://www.w9wze.org   
>
>