From signalone@mailman.qth.net  Fri Nov  1 01:38:27 2002
From: signalone@mailman.qth.net (Bob Sullivan)
Date: Thu, 31 Oct 2002 20:38:27 -0500
Subject: [SignalOne] Arcing in Final
In-Reply-To: <3DC12DF3.747.549C9F2@localhost>
Message-ID: <5.1.0.14.2.20021031203748.00fa0d90@mail.isquare.com>

John,


One source for the tube is
www.tubesandmore.com. 
$149.


73, Bob

W0YVA


At 01:19 PM 10/31/02 -0500, W2AGN wrote:

OK, this is driving me nuts! About
4 months ago I became the proud owner 

of a lovingly restored CX7A. It looks like new. First time I turned it


on...ka-pow, the 1 ohm resistor blew. Talking to the gentleman I bought


it from, it seems he had a simalr problem, and made some suggestions.



I found the {quot}collar{quot} on the tube loose, and the setscrew I
though might 

have been arcing. I tightened it up, and looked over the inside of the PA


with a magnifying glass. I could see no signs of arcing, so replaced the


1 ohm resistor.


All was fine, until after a month or so of no use, I fired it up the


other day. Ka-pow again. Sure enough, resistor was blown. This time I


replaced the ,005 3KV bypass. Turned it on, all seemed fine for about 5


minutes..then ka-pow again. Blew another 1 ohm resistor.


I can't see where it is arcing. I have a sinking feeling it might be the


tube arcing internally. 


Anyone had similar experience steer me where to look next? Also, 

suggestions as to where to purchase an 8072 for the final, at the best


price.


---

+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|       
http://www.w2agn.net

+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
_______________________________________________

SignalOne mailing list

SignalOne@mailman.qth.net

http://mailman.qth.net/mailman/listinfo/signalone

---------------------------------------------------------

E-commerce, Consulting, Publishing

Box 579, Great Falls, VA  22066 
703-450-7049  Fax: 703-450-7394
Check out The Small Business Advisor

http://www.isquare.com

---------------------------------------------------------






--- StripMime Report -- processed MIME parts ---
text/html (html body -- converted)
The reason this message is shown is because the post was in HTML
or had an attachment. Attachments are not allowed.
Please post in Plain-Text only.---

From signalone@mailman.qth.net  Fri Nov  1 00:32:23 2002
From: signalone@mailman.qth.net (Mac)
Date: Thu, 31 Oct 2002 18:32:23 -0600
Subject: [SignalOne] Arcing in Final
References: <3DC12DF3.747.549C9F2@localhost>
Message-ID: <02d601c2813e$25d581a0$0702a8c0@WorkGroup>

well it damn sure sounds real exciting at you QTH with ever time you power
this puppy up...  stay safe..  but I have no offer of technical help..
----- Original Message -----
From: "W2AGN" <w2agn@w2agn.net>
To: <signalone@mailman.qth.net>
Sent: Thursday, October 31, 2002 12:19 PM
Subject: [SignalOne] Arcing in Final


> OK, this is driving me nuts! About 4 months ago I became the proud owner
> of a lovingly restored CX7A. It looks like new. First time I turned it
> on...ka-pow, the 1 ohm resistor blew. Talking to the gentleman I bought
> it from, it seems he had a simalr problem, and made some suggestions.
>
> I found the "collar" on the tube loose, and the setscrew I though might
> have been arcing. I tightened it up, and looked over the inside of the PA
> with a magnifying glass. I could see no signs of arcing, so replaced the
> 1 ohm resistor.
>
> All was fine, until after a month or so of no use, I fired it up the
> other day. Ka-pow again. Sure enough, resistor was blown. This time I
> replaced the ,005 3KV bypass. Turned it on, all seemed fine for about 5
> minutes..then ka-pow again. Blew another 1 ohm resistor.
>
> I can't see where it is arcing. I have a sinking feeling it might be the
> tube arcing internally.
>
> Anyone had similar experience steer me where to look next? Also,
> suggestions as to where to purchase an 8072 for the final, at the best
> price.
>
> ---
> +-++-++-++-++-+   John L. Sielke
> |W||2||A||G||N|        http://www.w2agn.net
> +-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
> _______________________________________________
> SignalOne mailing list
> SignalOne@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/signalone


From signalone@mailman.qth.net  Fri Nov  1 01:42:20 2002
From: signalone@mailman.qth.net (Mac)
Date: Thu, 31 Oct 2002 19:42:20 -0600
Subject: [SignalOne] Arcing in Final
References: <3DC12DF3.747.549C9F2@localhost>
Message-ID: <035601c28147$eb84b840$0702a8c0@WorkGroup>

my flip comments were made in fun.. not to offend..  thanx  mac/mc
----- Original Message -----
From: "W2AGN" <w2agn@w2agn.net>
To: <signalone@mailman.qth.net>
Sent: Thursday, October 31, 2002 12:19 PM
Subject: [SignalOne] Arcing in Final


> OK, this is driving me nuts! About 4 months ago I became the proud owner
> of a lovingly restored CX7A. It looks like new. First time I turned it
> on...ka-pow, the 1 ohm resistor blew. Talking to the gentleman I bought
> it from, it seems he had a simalr problem, and made some suggestions.
>
> I found the "collar" on the tube loose, and the setscrew I though might
> have been arcing. I tightened it up, and looked over the inside of the PA
> with a magnifying glass. I could see no signs of arcing, so replaced the
> 1 ohm resistor.
>
> All was fine, until after a month or so of no use, I fired it up the
> other day. Ka-pow again. Sure enough, resistor was blown. This time I
> replaced the ,005 3KV bypass. Turned it on, all seemed fine for about 5
> minutes..then ka-pow again. Blew another 1 ohm resistor.
>
> I can't see where it is arcing. I have a sinking feeling it might be the
> tube arcing internally.
>
> Anyone had similar experience steer me where to look next? Also,
> suggestions as to where to purchase an 8072 for the final, at the best
> price.
>
> ---
> +-++-++-++-++-+   John L. Sielke
> |W||2||A||G||N|        http://www.w2agn.net
> +-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
> _______________________________________________
> SignalOne mailing list
> SignalOne@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/signalone


From signalone@mailman.qth.net  Fri Nov  1 13:57:00 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Fri, 01 Nov 2002 08:57:00 -0500
Subject: [SignalOne] Arcing in Final
In-Reply-To: <035601c28147$eb84b840$0702a8c0@WorkGroup>
Message-ID: <3DC241DC.21970.97FD0A3@localhost>

On 31 Oct 2002 at 19:42, Mac wrote:

> my flip comments were made in fun.. not to offend..  thanx  mac/mc


No offense taken. I have heard the XYL go "What in the H*ll was that?" 
more than once. Also, "What is that smell?"


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Fri Nov  1 16:44:29 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Fri, 01 Nov 2002 11:44:29 -0500
Subject: [SignalOne] CX7A arcing follow-up
Message-ID: <3DC2691D.1888.A192F5B@localhost>

Thanks to all who responded. S/1 owners are a great bunch.

It appears it is the tube. If I disconnect the socket, and apply B+, no 
arcing, but with socket connected, it blows the 1 ohm resistor. Hopefully 
have replacement on the way.

Oh, yes, one other think I learned. The CX7A power supply doesn't have 
much of a bleeder. It's OK, I'll be able to use that hand again in a day 
or two  ;-)


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Fri Nov  1 19:38:54 2002
From: signalone@mailman.qth.net (ki4en)
Date: Fri, 1 Nov 2002 14:38:54 -0500
Subject: [SignalOne] CX7A arcing follow-up
References: <3DC2691D.1888.A192F5B@localhost>
Message-ID: <000a01c281de$50495060$dd374004@net.dslverizon.net>

Hi.  I've been reading your mail about your arcing problem.
While a defective tube will cause the problem you describe I
have experienced the same thing in repairing such sets that
you might want to check:
    . Parasitics---check the parasitic suppressor resistors.
Sometimes the tube is good and is driven into saturation
when this happens.
    Bias components---I have seen CR-1 become erratic and
momentarily pull down the bias; a failure of C30 on the
driver board can cause the same problem.  Also, changing the
1.0 ohm/ 1.0 watt resistor to a 1.0 ohm/ 2.0 watt resistor
sometimes corrects the problem---worth a try if all else
fails.
Good luck, Jim, KI4EN.
----- Original Message -----
From: "W2AGN" <w2agn@w2agn.net>
To: <signalone@mailman.qth.net>
Sent: Friday, November 01, 2002 11:44 AM
Subject: [SignalOne] CX7A arcing follow-up


> Thanks to all who responded. S/1 owners are a great bunch.
>
> It appears it is the tube. If I disconnect the socket, and
apply B+, no
> arcing, but with socket connected, it blows the 1 ohm
resistor. Hopefully
> have replacement on the way.
>
> Oh, yes, one other think I learned. The CX7A power supply
doesn't have
> much of a bleeder. It's OK, I'll be able to use that hand
again in a day
> or two  ;-)
>
>
> ---
> +-++-++-++-++-+   John L. Sielke
> |W||2||A||G||N|        http://www.w2agn.net
> +-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
> _______________________________________________
> SignalOne mailing list
> SignalOne@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/signalone



From signalone@mailman.qth.net  Mon Nov  4 06:44:24 2002
From: signalone@mailman.qth.net (Graf Ulrich Ulm)
Date: Mon, 4 Nov 2002 07:44:24 +0100
Subject: [SignalOne] Arcing in Final
Message-ID: <DD56BED8E920D411ACDC0060087E3618012CB704@ulml040a.stg.siemens.de>

Hi,

why arcing? - this is probably a new replacement tube and it is oscillating!

73 Uli, DK4SX

-----Original Message-----
From: W2AGN [mailto:w2agn@w2agn.net]
Sent: Donnerstag, 31. Oktober 2002 19:20
To: signalone@mailman.qth.net
Subject: [SignalOne] Arcing in Final


OK, this is driving me nuts! About 4 months ago I became the proud owner 
of a lovingly restored CX7A. It looks like new. First time I turned it 
on...ka-pow, the 1 ohm resistor blew. Talking to the gentleman I bought 
it from, it seems he had a simalr problem, and made some suggestions. 

I found the "collar" on the tube loose, and the setscrew I though might 
have been arcing. I tightened it up, and looked over the inside of the PA 
with a magnifying glass. I could see no signs of arcing, so replaced the 
1 ohm resistor.

All was fine, until after a month or so of no use, I fired it up the 
other day. Ka-pow again. Sure enough, resistor was blown. This time I 
replaced the ,005 3KV bypass. Turned it on, all seemed fine for about 5 
minutes..then ka-pow again. Blew another 1 ohm resistor.

I can't see where it is arcing. I have a sinking feeling it might be the 
tube arcing internally. 

Anyone had similar experience steer me where to look next? Also, 
suggestions as to where to purchase an 8072 for the final, at the best 
price.

---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
_______________________________________________
SignalOne mailing list
SignalOne@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/signalone

From signalone@mailman.qth.net  Thu Nov  7 16:13:16 2002
From: signalone@mailman.qth.net (Jan C. Robbins)
Date: Thu, 07 Nov 2002 10:13:16 -0600
Subject: [SignalOne] 1030 Service info??
Message-ID: <3DCA911C.D1C88E64@cfu.net>

Hi All,
Can anyone refresh my memory about who services the 1030 CI these days? 
Would appreciate any contact info you can provide.  Many tks es vy 73 to
all!  Jan N0JR


From signalone@mailman.qth.net  Sat Nov  9 17:08:56 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Sat, 09 Nov 2002 12:08:56 -0500
Subject: [SignalOne] CX7A Arcing Update
Message-ID: <3DCCFAD8.18541.40720AD@localhost>

First, let me thank all of you who replied. Lots of good info. I have 
stored several messages in my "Saved" box.

I got a replacement tube today. Installed it, and let it "cook" for an 
hour. Viola! NO arcing when I hit the B+. 

Bad news :-(  I have no drive. Someone suggested the arcing might blow 
the driver transistor, and I guess it did. 

Jsut to check, I put the old tube back, and sure enough, it arced, and 
the 1 ohm blew. So it WAS the tube. (It would arc with no drive before). 
Put back new tube, replaced 1 ohm resistor, and all OK again.

Now,

1. Where is a good place to get replacement driver transistors?
2. Any hints on the easiest way to get at the thing. Looks like I have to 
remove the driver board, which means removing the readout board, etc. 
Correct?


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Mon Nov 11 07:07:53 2002
From: signalone@mailman.qth.net (Graf Ulrich Ulm)
Date: Mon, 11 Nov 2002 08:07:53 +0100
Subject: [SignalOne] CX7A Arcing Update
Message-ID: <DD56BED8E920D411ACDC0060087E3618012CB714@ulml040a.stg.siemens.de>

Hi,

try RF Parts for replacement transistors. They are very well equipped.

73 Uli, DK4SX

-----Original Message-----
From: W2AGN [mailto:w2agn@w2agn.net]
Sent: Samstag, 9. November 2002 18:09
To: signalone@mailman.qth.net
Subject: [SignalOne] CX7A Arcing Update


First, let me thank all of you who replied. Lots of good info. I have 
stored several messages in my "Saved" box.

I got a replacement tube today. Installed it, and let it "cook" for an 
hour. Viola! NO arcing when I hit the B+. 

Bad news :-(  I have no drive. Someone suggested the arcing might blow 
the driver transistor, and I guess it did. 

Jsut to check, I put the old tube back, and sure enough, it arced, and 
the 1 ohm blew. So it WAS the tube. (It would arc with no drive before). 
Put back new tube, replaced 1 ohm resistor, and all OK again.

Now,

1. Where is a good place to get replacement driver transistors?
2. Any hints on the easiest way to get at the thing. Looks like I have to 
remove the driver board, which means removing the readout board, etc. 
Correct?


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
_______________________________________________
SignalOne mailing list
SignalOne@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/signalone

From signalone@mailman.qth.net  Mon Nov 11 17:53:14 2002
From: signalone@mailman.qth.net (Mark, K5AM)
Date: Mon, 11 Nov 2002 17:53:14 +0000
Subject: [SignalOne] 8072 and driver damage
In-Reply-To: <3DCCFAD8.18541.40720AD@localhost>
Message-ID: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com>

At 17:08 2002-11-09,
W2AGN <w2agn@w2agn.net> wrote:
>Bad news :-(  I have no drive. Someone suggested the arcing might blow
>the driver transistor, and I guess it did.

------

The driver and 8072 circuit shown in

HF Circuits for a Homebrew Transceiver,
QEX, Nov/Dec, 2001, 20-42.

prevents driver damage from PA faults. This simple
two-component protection can easily be added
to a CX7.

The article also has an 8072 screen protection
circuit, an 8072 PA tank protection circuit, and other
information applicable to the CX7.

Information about obtaining copies of QEX articles
may be found at http://www.arrl.org/qex/#copies,
http://www.arrl.org/members-only/artcopies.html
and reprints@arrl.org.



73,

Mark, K5AM    DM62ni

-----
Mark Mandelkern
Las Cruces, New Mexico, USA
k5am@zianet.com
First callsign: W9ECV, Milwaukee, 1948.
10 band DXCC confirmed. 134 countries on 6 meters.
Homebrew station:
<http://www.zianet.com/k5am/ncj/ncj.html>




From signalone@mailman.qth.net  Mon Nov 11 18:11:14 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Mon, 11 Nov 2002 13:11:14 -0500
Subject: [SignalOne] 8072 and driver damage
In-Reply-To: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com>
References: <3DCCFAD8.18541.40720AD@localhost>
Message-ID: <3DCFAC72.24836.E8D84B0@localhost>

On 11 Nov 2002 at 17:53, Mark, K5AM wrote:

> 
> At 17:08 2002-11-09,
> W2AGN <w2agn@w2agn.net> wrote:
> >Bad news :-(  I have no drive. Someone suggested the arcing might blow
> >the driver transistor, and I guess it did.
> 
> ------
> 
> The driver and 8072 circuit shown in
> 
> HF Circuits for a Homebrew Transceiver,
> QEX, Nov/Dec, 2001, 20-42.
> 
> prevents driver damage from PA faults. This simple
> two-component protection can easily be added
> to a CX7.
> 
Thanks, Dave. Will see about that. Kind of closing the barn door after 
the horse gets out, though..,..

---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Mon Nov 11 19:11:01 2002
From: signalone@mailman.qth.net (Ed Tanton)
Date: Mon, 11 Nov 2002 14:11:01 -0500
Subject: [SignalOne] 8072 and driver damage
In-Reply-To: <3DCFAC72.24836.E8D84B0@localhost>
References: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com>
 <3DCCFAD8.18541.40720AD@localhost>
Message-ID: <5.1.1.6.2.20021111140952.01f4bfe8@pop.earthlink.net>

Hi John... I just ordered the 2001 QEX CD from ARRL... will be happy to 
forward the PDFs/JPGs/etc..

At 01:11 PM 2002-11-11, you wrote:
>On 11 Nov 2002 at 17:53, Mark, K5AM wrote:
>
> >
> > At 17:08 2002-11-09,
> > W2AGN <w2agn@w2agn.net> wrote:
> > >Bad news :-(  I have no drive. Someone suggested the arcing might blow
> > >the driver transistor, and I guess it did.
> >
> > ------
> >
> > The driver and 8072 circuit shown in
> >
> > HF Circuits for a Homebrew Transceiver,
> > QEX, Nov/Dec, 2001, 20-42.
> >
> > prevents driver damage from PA faults. This simple
> > two-component protection can easily be added
> > to a CX7.
> >
>Thanks, Dave. Will see about that. Kind of closing the barn door after
>the horse gets out, though..,..
>
>---
>+-++-++-++-++-+   John L. Sielke
>|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
>+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
>_______________________________________________
>SignalOne mailing list
>SignalOne@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/signalone

73 Ed Tanton N4XY <n4xy@earthlink.net>

Ed Tanton N4XY
189 Pioneer Trail
Marietta, GA 30068-3466

website: http://www.n4xy.com

All emails <IN> & <OUT> checked by
Norton AntiVirus with AutoProtect

LM: ARRL QCWA AMSAT & INDEXA;
SEDXC NCDXA GACW QRP-ARCI
OK-QRP QRP-L #758 K2 (FT) #00057



From signalone@mailman.qth.net  Mon Nov 11 19:14:31 2002
From: signalone@mailman.qth.net (Ed Tanton)
Date: Mon, 11 Nov 2002 14:14:31 -0500
Subject: [SignalOne] 8072 and driver damage
In-Reply-To: <3DCFAC72.24836.E8D84B0@localhost>
References: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com>
 <3DCCFAD8.18541.40720AD@localhost>
Message-ID: <5.1.1.6.2.20021111141107.01f4e0f8@pop.earthlink.net>

P.S. Looking at the bottom of your CX-7, with the cabinet OFF... does YOUR 
RF compartment have a shield / cover? Mine didn't... and just before I had 
to just button mine up due to my wife's annual Christmas Cleanup Frenzy, 
with a new tube mine was-I think-self-oscillating... with the whole case 
off. And looking at it, I got to wondering about that after the fact, so to 
speak.



73 Ed Tanton N4XY <n4xy@earthlink.net>

Ed Tanton N4XY
189 Pioneer Trail
Marietta, GA 30068-3466

website: http://www.n4xy.com

All emails <IN> & <OUT> checked by
Norton AntiVirus with AutoProtect

LM: ARRL QCWA AMSAT & INDEXA;
SEDXC NCDXA GACW QRP-ARCI
OK-QRP QRP-L #758 K2 (FT) #00057



From signalone@mailman.qth.net  Mon Nov 11 21:50:31 2002
From: signalone@mailman.qth.net (John Kenney)
Date: Mon, 11 Nov 2002 13:50:31 -0800
Subject: [SignalOne] 8072 and driver damage
References: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com> <3DCCFAD8.18541.40720AD@localhost> <5.1.1.6.2.20021111140952.01f4bfe8@pop.earthlink.net>
Message-ID: <000801c289cc$5bcd2560$9dd2ffd8@johnkenn>

Hi - I would appreciate a copy.
Thanks,
John Kenney, W7COI

----- Original Message -----
From: "Ed Tanton" <n4xy@earthlink.net>
To: <signalone@mailman.qth.net>
Sent: Monday, November 11, 2002 11:11 AM
Subject: Re: [SignalOne] 8072 and driver damage


> Hi John... I just ordered the 2001 QEX CD from ARRL... will be happy to
> forward the PDFs/JPGs/etc..
>
> At 01:11 PM 2002-11-11, you wrote:
> >On 11 Nov 2002 at 17:53, Mark, K5AM wrote:
> >
> > >
> > > At 17:08 2002-11-09,
> > > W2AGN <w2agn@w2agn.net> wrote:
> > > >Bad news :-(  I have no drive. Someone suggested the arcing might
blow
> > > >the driver transistor, and I guess it did.
> > >
> > > ------
> > >
> > > The driver and 8072 circuit shown in
> > >
> > > HF Circuits for a Homebrew Transceiver,
> > > QEX, Nov/Dec, 2001, 20-42.
> > >
> > > prevents driver damage from PA faults. This simple
> > > two-component protection can easily be added
> > > to a CX7.
> > >
> >Thanks, Dave. Will see about that. Kind of closing the barn door after
> >the horse gets out, though..,..
> >
> >---
> >+-++-++-++-++-+   John L. Sielke
> >|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
> >+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
> >_______________________________________________
> >SignalOne mailing list
> >SignalOne@mailman.qth.net
> >http://mailman.qth.net/mailman/listinfo/signalone
>
> 73 Ed Tanton N4XY <n4xy@earthlink.net>
>
> Ed Tanton N4XY
> 189 Pioneer Trail
> Marietta, GA 30068-3466
>
> website: http://www.n4xy.com
>
> All emails <IN> & <OUT> checked by
> Norton AntiVirus with AutoProtect
>
> LM: ARRL QCWA AMSAT & INDEXA;
> SEDXC NCDXA GACW QRP-ARCI
> OK-QRP QRP-L #758 K2 (FT) #00057
>
>
> _______________________________________________
> SignalOne mailing list
> SignalOne@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/signalone


From signalone@mailman.qth.net  Mon Nov 11 22:53:03 2002
From: signalone@mailman.qth.net (Ed Tanton)
Date: Mon, 11 Nov 2002 17:53:03 -0500
Subject: [SignalOne] 8072 and driver damage
In-Reply-To: <000801c289cc$5bcd2560$9dd2ffd8@johnkenn>
References: <5.1.0.14.0.20021111174652.00a26b20@mail.zianet.com>
 <3DCCFAD8.18541.40720AD@localhost>
 <5.1.1.6.2.20021111140952.01f4bfe8@pop.earthlink.net>
Message-ID: <5.1.1.6.2.20021111175113.01f86ce0@pop.earthlink.net>

Sure John... it may take a week or so to get the CD... and assuming nobody 
from the ARRL jumps on me for offering copies... I had actually meant that 
to be a private message to John-to avoid such problems from 
copyright-minded folks... but so far, no threats, etc. [grin].

At 04:50 PM 2002-11-11, you wrote:
>Hi - I would appreciate a copy.
>Thanks,
>John Kenney, W7COI
>
>----- Original Message -----
>From: "Ed Tanton" <n4xy@earthlink.net>
>To: <signalone@mailman.qth.net>
>Sent: Monday, November 11, 2002 11:11 AM
>Subject: Re: [SignalOne] 8072 and driver damage
>
>
> > Hi John... I just ordered the 2001 QEX CD from ARRL... will be happy to
> > forward the PDFs/JPGs/etc..
> >
> > At 01:11 PM 2002-11-11, you wrote:
> > >On 11 Nov 2002 at 17:53, Mark, K5AM wrote:
> > >
> > > >
> > > > At 17:08 2002-11-09,
> > > > W2AGN <w2agn@w2agn.net> wrote:
> > > > >Bad news :-(  I have no drive. Someone suggested the arcing might
>blow
> > > > >the driver transistor, and I guess it did.
> > > >
> > > > ------
> > > >
> > > > The driver and 8072 circuit shown in
> > > >
> > > > HF Circuits for a Homebrew Transceiver,
> > > > QEX, Nov/Dec, 2001, 20-42.
> > > >
> > > > prevents driver damage from PA faults. This simple
> > > > two-component protection can easily be added
> > > > to a CX7.
> > > >
> > >Thanks, Dave. Will see about that. Kind of closing the barn door after
> > >the horse gets out, though..,..
> > >
> > >---
> > >+-++-++-++-++-+   John L. Sielke
> > >|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
> > >+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
> > >_______________________________________________
> > >SignalOne mailing list
> > >SignalOne@mailman.qth.net
> > >http://mailman.qth.net/mailman/listinfo/signalone
> >
> > 73 Ed Tanton N4XY <n4xy@earthlink.net>
> >
> > Ed Tanton N4XY
> > 189 Pioneer Trail
> > Marietta, GA 30068-3466
> >
> > website: http://www.n4xy.com
> >
> > All emails <IN> & <OUT> checked by
> > Norton AntiVirus with AutoProtect
> >
> > LM: ARRL QCWA AMSAT & INDEXA;
> > SEDXC NCDXA GACW QRP-ARCI
> > OK-QRP QRP-L #758 K2 (FT) #00057
> >
> >
> > _______________________________________________
> > SignalOne mailing list
> > SignalOne@mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/signalone
>
>_______________________________________________
>SignalOne mailing list
>SignalOne@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/signalone

73 Ed Tanton N4XY <n4xy@earthlink.net>

Ed Tanton N4XY
189 Pioneer Trail
Marietta, GA 30068-3466

website: http://www.n4xy.com

All emails <IN> & <OUT> checked by
Norton AntiVirus with AutoProtect

LM: ARRL QCWA AMSAT & INDEXA;
SEDXC NCDXA GACW QRP-ARCI
OK-QRP QRP-L #758 K2 (FT) #00057



From signalone@mailman.qth.net  Sat Nov 16 18:19:48 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Sat, 16 Nov 2002 13:19:48 -0500
Subject: [SignalOne] CX7A Drive (was:arcing)
Message-ID: <3DD645F4.12039.CEE784@localhost>

This thing is driving me nuts! 

After replacing final tube, I had no more arcing, but I thought driver 
transistor is blown, since no output, and only resting Plate Current in 
"TUNE."

Resting plate current OK.  Screen Voltage 320V. 

The odd thing is, using an RF  diode probe, I see RF at the output of C30 
on the driver board, which is variable with the drive control. Also on 
the grid pin(s) of the 8072.  The RF Driver transistor gets warm (not 
hot) after a few minutes key down, which tells me t's not blown. Still, 
no drive in the "drive" meter position. 

I am hoping I won't have to pull the driver board, as to do so it appears 
I must remove 2 other boards to get at the screws. (All 3 on the bottom 
are in place). 

Am I missing something obvious? 
---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Sat Nov 16 19:08:03 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Sat, 16 Nov 2002 14:08:03 -0500
Subject: [SignalOne] Re: More CX7A Drive (was:arcing)
Message-ID: <3DD65143.31871.FB1601@localhost>

On 16 Nov 2002 at 13:19, signalone@mailman.qth.net wrote:

The odd thing is, using an RF  diode probe, I see RF at the output of C30 

on the driver board, which is variable with the drive control. Also on 
the grid pin(s) of the 8072.  The RF Driver transistor gets warm (not 
hot) after a few minutes key down, which tells me t's not blown. Still, 
no drive in the "drive" meter position. 

----More-----

I checked at input and output of driver transistor. Getting excellent 
amplification, voltages normal. Plenty of RF on grid of 8072, but still 
acting like no drive. (i.e, no output, no plate current above resting 
(100ma), regardless of "output" knob setting in Tune Position. I even 
tried a THIRD tube, which I just acquired, but no difference. 

It has got to be something simple I am over looking.


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

From signalone@mailman.qth.net  Mon Nov 18 19:25:36 2002
From: signalone@mailman.qth.net (David Bertman)
Date: Mon, 18 Nov 2002 11:25:36 -0800
Subject: [SignalOne] Re: More CX7A Drive (was:arcing)
Message-ID: <OFA203E769.39501D4B-ON88256C75.006A503B@boulder.ibm.com>

The simplest thing I know of is the connection to RF driver board.  It
LIKES to get loose.  Also, though it is not the case here, I have seen
drive problems due to a blown 34 volt supply.  With a system which uses
the new audio PA (like John's) the driver is the only unit affected if
this power goes.

Dave AB7B


                                                                                                                                    
                      W2AGN                                                                                                         
                      <w2agn@w2agn.net>           To:       signalone@mailman.qth.net                                               
                      Sent by:                    cc:                                                                               
                      signalone-admin@mail        Subject:  [SignalOne] Re: More CX7A Drive (was:arcing)                            
                      man.qth.net                                                                                                   
                                                                                                                                    
                                                                                                                                    
                      11/16/2002 11:08 AM                                                                                           
                      Please respond to                                                                                             
                      signalone                                                                                                     
                                                                                                                                    
                                                                                                                                    



On 16 Nov 2002 at 13:19, signalone@mailman.qth.net wrote:

The odd thing is, using an RF  diode probe, I see RF at the output of C30

on the driver board, which is variable with the drive control. Also on
the grid pin(s) of the 8072.  The RF Driver transistor gets warm (not
hot) after a few minutes key down, which tells me t's not blown. Still,
no drive in the "drive" meter position.

----More-----

I checked at input and output of driver transistor. Getting excellent
amplification, voltages normal. Plenty of RF on grid of 8072, but still
acting like no drive. (i.e, no output, no plate current above resting
(100ma), regardless of "output" knob setting in Tune Position. I even
tried a THIRD tube, which I just acquired, but no difference.

It has got to be something simple I am over looking.


---
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS
_______________________________________________
SignalOne mailing list
SignalOne@mailman.qth.net
http://mailman.qth.net/mailman/listinfo/signalone






From signalone@mailman.qth.net  Mon Nov 18 19:59:29 2002
From: signalone@mailman.qth.net (W2AGN)
Date: Mon, 18 Nov 2002 14:59:29 -0500
Subject: [SignalOne] Re: More CX7A Drive (was:arcing)
In-Reply-To: <OFA203E769.39501D4B-ON88256C75.006A503B@boulder.ibm.com>
Message-ID: <3DD90051.1553.B777E11@localhost>

On 18 Nov 2002 at 11:25, David Bertman wrote:

> 
> The simplest thing I know of is the connection to RF driver board.  It
> LIKES to get loose.  Also, though it is not the case here, I have seen
> drive problems due to a blown 34 volt supply.  With a system which uses
> the new audio PA (like John's) the driver is the only unit affected if
> this power goes.
> 
> Dave AB7B

I have disconnected and reconnected to rf connection. Also I have the 
same RF at the grid of the tube as I do at the output of the driver, so 
it is getting there. 

Had to put it aside for a day or two while I think about it. I did 
acquire a new driver transistor, should that somehow prove the problem, 
although I seem to have enough RF that it should at least show some 
drive.

--
+-++-++-++-++-+   John L. Sielke
|W||2||A||G||N|        http://www.w2agn.net [UPDATED]
+-++-++-++-++-+    Ex-K3HLU,TF2WKT,W7JEF,W4MPC,N4JS

