|[AMRadio] fs/ft: Eimac 4CX250B - Unknown Condition|
Rev. Robert P. Chrysafis
kc8gpd at hotmail.com
Thu Nov 29 09:42:27 EST 2007
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.
> ----- 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
>> around my house for quite some time. I have no use for it as i'm into
>> 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
>> My interests are Part 15 AM Microcasting and Computers.
>> Thank You,
>> Rev. Robert P. Chrysafis
>> Universal Life Ministries
>> Moderator Hunterdonfree
>> Moderator NeighborhoodInformer NJ/PA
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