[AMRadio] fs/ft: Eimac 4CX250B - Unknown Condition


Rev. Robert P. Chrysafis kc8gpd at hotmail.com
Thu Nov 29 09:42:27 EST 2007


Ok,

I don't know much about this high power stuff. highest power tube tranny i 
have is 36 Watts on the AM BCB for carrier current use.

and actually that is the only tube tx i have. it's going to be a learning 
experience to get it going again.

----- Original Message ----- 
From: "Brett Gazdzinski" <brett.gazdzinski at verizon.net>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Thursday, November 29, 2007 9:37 AM
Subject: Re: [AMRadio] fs/ft: Eimac 4CX250B - Unknown Condition


>I avoid 4cx250  pull outs as they are almost always bad.
> They may test fine, but they arc over after a while in use.
> I have about 30 of them that do that.
>
> As they are used, the stuff they made to coat the cathode
> (so it emits electrons) gets deposited all over inside the tube,
> and at some point they start arcing over.
> It just seems to come down to run time (filiments on).
>
> They tend to work for a while, then arc, and the more
> you use them the more they arc, till next time when you
> start over again, each time getting shorter before they arc.
>
> Maybe reducing the voltage to say 1000 volts
> (down from 2000) might give them more time.
>
> I consider these tubes worthless unless they were not used
> or have low hours on them.
>
> Not sure what new ones go for, I got 4 new ones a few years ago
> for $160.00, used ones used to be $5.00 and not usualy worth that.
>
> Brett
> N2DTS
>
>
>
>
> ----- Original Message ----- 
> From: "Rev. Robert P. Chrysafis" <kc8gpd at hotmail.com>
> To: <AMRadio at mailman.qth.net>
> Sent: Thursday, November 29, 2007 9:25 AM
> Subject: [AMRadio] fs/ft: Eimac 4CX250B - Unknown Condition
>
>
>> I got this from a radio station in a lot of stuff and it has been 
>> floating
>> around my house for quite some time. I have no use for it as i'm into 
>> QRP.
> I
>> have no idea if it works or not. It looks like it's in good condition.
>>
>> I'll swap it for an interesting technical trinket or best cash offer plus
>> shipping.
>>
>> My interests are Part 15 AM Microcasting and Computers.
>>
>>
>> Thank You,
>>
>> Rev. Robert P. Chrysafis
>> Universal Life Ministries
>> http://www.ulc.org
>>
>> Moderator Hunterdonfree
>> http://groups.yahoo.com/group/hunterdonfree
>> Moderator NeighborhoodInformer NJ/PA
>> http://groups.yahoo.com/group/NeighborhoodInformerNewJersey
>> http://groups.yahoo.com/group/NeighborhoodInformerpennsylvania
>>
>> ______________________________________________________________
>> Our Main Website: http://www.amfone.net
>> AMRadio mailing list
>> List Rules (must read!): http://w5ami.net/amradiofaq.html
>> List Home: http://mailman.qth.net/mailman/listinfo/amradio
>> Help: http://mailman.qth.net/mmfaq.html
>> Post: mailto:AMRadio at mailman.qth.net
>> To unsubscribe, send an email to amradio-request at mailman.qth.net with
>> the word unsubscribe in the message body.
>
> ______________________________________________________________
> Our Main Website: http://www.amfone.net
> AMRadio mailing list
> List Rules (must read!): http://w5ami.net/amradiofaq.html
> List Home: http://mailman.qth.net/mailman/listinfo/amradio
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:AMRadio at mailman.qth.net
> To unsubscribe, send an email to amradio-request at mailman.qth.net with
> the word unsubscribe in the message body.
> 



More information about the AMRadio mailing list

This page last updated 10 Dec 2017.