I have seen this many times. More than one cause. One cause that I have seen
often is a tube goes gassy and arks over. It takes out the metering
resisters and grid current often gets affected by this. It is easy to spot
this as the resistors split and go into pieces. If memory serves me those
resistors() are in the front panel near multi meter switch (if memory serves
me). I should have looked up my service manual for that unit to be sure, but
I did not, so this is just from memory.
As far as the diode showing "13.5 K ohm" that can be the fault of you ohm
meter. Most modern ohm meters do not use enough voltage to turn on a diode
or transistor for testing. You will have to use a higher voltage. Consider
using a 1k resistor in series with the diode and applying 12vdc one
direction you will have no current draw and the other you will have current.
You will see around .6 volts across the diode in one direction and 12 volts
in the other.
If you need manual, feel free to email me direct (email below) and I will
email you a copy.
73, Bruce, W8HW, w8hw@att.net
I FIX broken radios. If it transmit, I fix it.
----- Original Message -----
From: <amps-request@contesting.com>
To: <amps@contesting.com>
Sent: Thursday, May 26, 2011 8:38 PM
Subject: Amps Digest, Vol 101, Issue 39
> Send Amps mailing list submissions to
> amps@contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/amps
> or, via email, send a message with subject or body 'help' to
> amps-request@contesting.com
>
> You can reach the person managing the list at
> amps-owner@contesting.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Amps digest..."
>
>
> Today's Topics:
>
> 1. Re: Henry 2KD-5 Problem (TexasRF@aol.com)
> 2. Re: Henry 2KD-5 Problem (Mitch Cox)
> 3. Re: Henry 2KD-5 Problem (TexasRF@aol.com)
> 4. Re: Henry 2KD-5 Problem (Jim W7RY)
> 5. Re: Henry 2KD-5 Problem (Mitch Cox)
> 6. 8877 or 3CPX1500 Wanted (Jim W7RY)
> 7. Re: Henry 2KD-5 Problem (k7fm)
> 8. Re: T/R relay (Paul Decker)
> 9. Re: T-T Titan with Pro III Question (Jim Brown)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 26 May 2011 18:38:01 EDT
> From: TexasRF@aol.com
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: kb5gt@cableone.net, amps@contesting.com
> Message-ID: <ece6c.3508e002.3b103049@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Hi Ed, sounds like a leakage to ground somewhere on the B+ side of the
> plate supply. Perhaps a HV feed through lost it's insulation or plate
> bypass or
> some other component in the B+ circuit has developed a leakage path to
> chassis/ground.
>
> 73,
> Gerald K5GW
>
>
>
>
> In a message dated 5/26/2011 5:18:23 P.M. Central Daylight Time,
> kb5gt@cableone.net writes:
>
> Last night I was using my 2KD-5, and it was working fine. After making
> several transmissions with no problem, it made a loud pop when keyed. Now
> the grid current indication goes off scale in the negative direction as
> soon
> as it is turned on, and stays there even with drive applied. It also has
> plate current flowing ( about 300 mA ) even when not keyed. It is still
> working and has output.
> I have to get someone to move it to my workbench due to a back injury, so
> all I've done so far is to remove the top. The bias diode reads 13.5 Kohm
> in
> both directions when checked with one end of the 220 Ohm parallel
> resistor
> lifted, but I see nothing that made the loud pop, so far.
> When I get it on the bench I can get into it, but wondered if anyone else
> had seen these problems in this or a similar amplifier.
> Thanks & 73,
> Ed, KB5GT
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 26 May 2011 18:41:20 -0400
> From: "Mitch Cox" <ww4cox@embarqmail.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: <TexasRF@aol.com>, <kb5gt@cableone.net>, <amps@contesting.com>
> Message-ID: <AA38700EC7BF4808AF905539B1F15E63@w4cox057538544>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Grid to filament short in one tube.
> ----- Original Message -----
> From: TexasRF@aol.com
> To: kb5gt@cableone.net ; amps@contesting.com
> Sent: Thursday, May 26, 2011 6:38 PM
> Subject: Re: [Amps] Henry 2KD-5 Problem
>
>
> Hi Ed, sounds like a leakage to ground somewhere on the B+ side of the
> plate supply. Perhaps a HV feed through lost it's insulation or plate
> bypass or
> some other component in the B+ circuit has developed a leakage path to
> chassis/ground.
>
> 73,
> Gerald K5GW
>
>
>
>
> In a message dated 5/26/2011 5:18:23 P.M. Central Daylight Time,
> kb5gt@cableone.net writes:
>
> Last night I was using my 2KD-5, and it was working fine. After making
> several transmissions with no problem, it made a loud pop when keyed.
> Now
> the grid current indication goes off scale in the negative direction as
> soon
> as it is turned on, and stays there even with drive applied. It also has
> plate current flowing ( about 300 mA ) even when not keyed. It is still
> working and has output.
> I have to get someone to move it to my workbench due to a back injury,
> so
> all I've done so far is to remove the top. The bias diode reads 13.5
> Kohm
> in
> both directions when checked with one end of the 220 Ohm parallel
> resistor
> lifted, but I see nothing that made the loud pop, so far.
> When I get it on the bench I can get into it, but wondered if anyone
> else
> had seen these problems in this or a similar amplifier.
> Thanks & 73,
> Ed, KB5GT
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1375 / Virus Database: 1509/3660 - Release Date: 05/25/11
>
>
> ------------------------------
>
> Message: 3
> Date: Thu, 26 May 2011 18:41:14 EDT
> From: TexasRF@aol.com
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: ww4cox@embarqmail.com, kb5gt@cableone.net, amps@contesting.com
> Message-ID: <ed02a.40e9d096.3b10310a@aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> Which can be confirmed by removing the tube(s).
>
> 73,
> Gerald K5GW
>
>
>
> In a message dated 5/26/2011 5:32:26 P.M. Central Daylight Time,
> ww4cox@embarqmail.com writes:
>
> You have a shorted tube.
> ----- Original Message -----
> From: ED MCKIE
> To: amps@contesting.com
> Sent: Thursday, May 26, 2011 6:18 PM
> Subject: [Amps] Henry 2KD-5 Problem
>
>
> Last night I was using my 2KD-5, and it was working fine. After making
> several transmissions with no problem, it made a loud pop when keyed. Now
> the grid current indication goes off scale in the negative direction as
> soon
> as it is turned on, and stays there even with drive applied. It also has
> plate current flowing ( about 300 mA ) even when not keyed. It is still
> working and has output.
> I have to get someone to move it to my workbench due to a back injury, so
> all I've done so far is to remove the top. The bias diode reads 13.5 Kohm
> in
> both directions when checked with one end of the 220 Ohm parallel
> resistor
> lifted, but I see nothing that made the loud pop, so far.
> When I get it on the bench I can get into it, but wondered if anyone else
> had seen these problems in this or a similar amplifier.
> Thanks & 73,
> Ed, KB5GT
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1375 / Virus Database: 1509/3660 - Release Date: 05/25/11
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 4
> Date: Thu, 26 May 2011 15:42:28 -0700
> From: "Jim W7RY" <w7ry@inbox.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: "Mitch Cox" <ww4cox@embarqmail.com>, "ED MCKIE"
> <kb5gt@cableone.net>, <amps@contesting.com>
> Message-ID: <AF3C55E264804E5BB5FEB5CAA92E12AF@Laptop>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Agreed!
>
> But you can't just pull one tube at a time because the filaments are in
> series. You most likely have other parts destroyed by the tube short.
>
>
> 73
> Jim W7RY
>
>
>
> --------------------------------------------------
> From: "Mitch Cox" <ww4cox@embarqmail.com>
> Sent: Thursday, May 26, 2011 3:32 PM
> To: "ED MCKIE" <kb5gt@cableone.net>; <amps@contesting.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
>
>> You have a shorted tube.
>> ----- Original Message -----
>> From: ED MCKIE
>> To: amps@contesting.com
>> Sent: Thursday, May 26, 2011 6:18 PM
>> Subject: [Amps] Henry 2KD-5 Problem
>>
>>
>> Last night I was using my 2KD-5, and it was working fine. After making
>> several transmissions with no problem, it made a loud pop when keyed.
>> Now
>> the grid current indication goes off scale in the negative direction as
>> soon
>> as it is turned on, and stays there even with drive applied. It also has
>> plate current flowing ( about 300 mA ) even when not keyed. It is still
>> working and has output.
>> I have to get someone to move it to my workbench due to a back injury,
>> so
>> all I've done so far is to remove the top. The bias diode reads 13.5
>> Kohm
>> in
>> both directions when checked with one end of the 220 Ohm parallel
>> resistor
>> lifted, but I see nothing that made the loud pop, so far.
>> When I get it on the bench I can get into it, but wondered if anyone
>> else
>> had seen these problems in this or a similar amplifier.
>> Thanks & 73,
>> Ed, KB5GT
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1375 / Virus Database: 1509/3660 - Release Date: 05/25/11
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>>
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1375 / Virus Database: 1509/3662 - Release Date: 05/26/11
>>
>
>
> ------------------------------
>
> Message: 5
> Date: Thu, 26 May 2011 18:55:47 -0400
> From: "Mitch Cox" <ww4cox@embarqmail.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: "Jim W7RY" <w7ry@inbox.com>, "ED MCKIE" <kb5gt@cableone.net>,
> <amps@contesting.com>
> Message-ID: <3B9A9C324061445CB29729150B96FA5F@w4cox057538544>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Since the grids are grounded to the chassis most likely got a meter shunt
> resistor or 2.
> ----- Original Message -----
> From: Jim W7RY
> To: Mitch Cox ; ED MCKIE ; amps@contesting.com
> Sent: Thursday, May 26, 2011 6:42 PM
> Subject: Re: [Amps] Henry 2KD-5 Problem
>
>
> Agreed!
>
> But you can't just pull one tube at a time because the filaments are in
> series. You most likely have other parts destroyed by the tube short.
>
>
> 73
> Jim W7RY
>
>
>
> --------------------------------------------------
> From: "Mitch Cox" <ww4cox@embarqmail.com>
> Sent: Thursday, May 26, 2011 3:32 PM
> To: "ED MCKIE" <kb5gt@cableone.net>; <amps@contesting.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
>
> > You have a shorted tube.
> > ----- Original Message -----
> > From: ED MCKIE
> > To: amps@contesting.com
> > Sent: Thursday, May 26, 2011 6:18 PM
> > Subject: [Amps] Henry 2KD-5 Problem
> >
> >
> > Last night I was using my 2KD-5, and it was working fine. After making
> > several transmissions with no problem, it made a loud pop when keyed.
> Now
> > the grid current indication goes off scale in the negative direction
> as
> > soon
> > as it is turned on, and stays there even with drive applied. It also
> has
> > plate current flowing ( about 300 mA ) even when not keyed. It is
> still
> > working and has output.
> > I have to get someone to move it to my workbench due to a back
> injury,
> > so
> > all I've done so far is to remove the top. The bias diode reads 13.5
> Kohm
> > in
> > both directions when checked with one end of the 220 Ohm parallel
> > resistor
> > lifted, but I see nothing that made the loud pop, so far.
> > When I get it on the bench I can get into it, but wondered if anyone
> > else
> > had seen these problems in this or a similar amplifier.
> > Thanks & 73,
> > Ed, KB5GT
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 10.0.1375 / Virus Database: 1509/3660 - Release Date:
> 05/25/11
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
> >
> >
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 10.0.1375 / Virus Database: 1509/3662 - Release Date: 05/26/11
> >
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1375 / Virus Database: 1509/3660 - Release Date: 05/25/11
>
>
> ------------------------------
>
> Message: 6
> Date: Thu, 26 May 2011 16:24:55 -0700
> From: "Jim W7RY" <w7ry@inbox.com>
> Subject: [Amps] 8877 or 3CPX1500 Wanted
> To: "AMPS" <amps@contesting.com>
> Message-ID: <8336913116354E7B992FFE992DC1E351@Laptop>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Does anyone have a excellent 8877 or 3CPX1500 tube for sale? Please let
> me know. I'm shopping around right now. w7ry at arrl . net
>
> Thanks
> 73
> Jim W7RY
>
>
> ------------------------------
>
> Message: 7
> Date: Thu, 26 May 2011 17:20:27 -0700
> From: "k7fm" <k7fm@teleport.com>
> Subject: Re: [Amps] Henry 2KD-5 Problem
> To: "ED MCKIE" <kb5gt@cableone.net>, <amps@contesting.com>
> Message-ID: <2E73337362E3493FA2F4D5B3F53A6B95@COLIN>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> "The bias diode reads 13.5 K ohm in both directions when checked with one
> end of the 220 Ohm parallel resistor
> lifted,"
>
> Ed, a normal dvm will check a single diode, but when you have diodes in
> series, as in a bias diode, the normal dvm will not work. Say you have 7
> diodes in series, the voltage drop would be 4 - 5 volts, so you need more
> than that to overcome the drop.
>
> A 9 volt battery as a source should work ok. One direction, the meter
> will
> read 4 volts, the other direction it will read zero.
>
> 73, Colin K7FM
>
>
>
> ------------------------------
>
> Message: 8
> Date: Fri, 27 May 2011 00:36:12 +0000 (UTC)
> From: Paul Decker <kg7hf@comcast.net>
> Subject: Re: [Amps] T/R relay
> To: amps@contesting.com
> Message-ID:
> <509589696.809743.1306456572487.JavaMail.root@sz0009a.westchester.pa.mail.comcast.net>
>
> Content-Type: text/plain; charset=utf-8
>
>
>
>
>
> Thanks Steve, that is kinda what I figured.? I thought I tried them at VHF
> and didn't have any luck getting them to work.
>
>
>
> I found this one on digikey, it's a bit expensive though:
>
> http://search.digikey.com/scripts/dksearch/dksus.dll?Detail&name=PB1252CT-ND
>
>
>
> For that price I might as well get another tohtsu CX-140 or something like
> that.
>
>
>
>
>
> Paul
>
>
>
>
>
>
>
>
>
>
>
>
>
> ?? 5. Re: T/R relay (Steve Thompson)
>
> Date: Thu, 26 May 2011 22:45:24 +0100
> From: Steve Thompson <g8gsq72@gmail.com>
> Subject: Re: [Amps] T/R relay
> To: amps@contesting.com
> Message-ID: <4DDEC9F4.2050908@gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I've used similar types at VHF with bits of capacitance to tune
> out the inductance of the internals but found them too touchy at
> UHF. There's also the issue of skin effect and how plating behaves
> at higher frequencies.
>
> For just a few $ you can get relays like Omron G6Y/G6Z which are
> rated for 1 or 2GHz. I can't recall part numbers but I'm sure some
> ??of them (maybe Siemens/NAIS/Aromat brand) are rated for 10 or
> 20W at UHF.
>
> Steve
>
>
>
>
> ------------------------------
>
> Message: 9
> Date: Thu, 26 May 2011 17:38:32 -0700
> From: Jim Brown <jim@audiosystemsgroup.com>
> Subject: Re: [Amps] T-T Titan with Pro III Question
> To: amps@contesting.com
> Message-ID: <4DDEF288.1050505@audiosystemsgroup.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 5/26/2011 9:02 AM, Bob Arenella wrote:
>> Anyone using a Titan 425 with a Pro III? Is it necessary to use a
>> keying buffer between the rig& amp?
>
> The control inputs of the Titan 425 are the base of a chip that you pull
> to ground to put in TX mode. It draws VERY little current, and it's not
> bitchy about how good the pull to ground is.
>
> You can download pdf schematics at
> http://audiosystemsgroup.com/publish.htm
>
> There CAN be an issue with TIMING of the keying. The Titan won't let you
> transmit until the TR relay has pulled in, and that takes about 8-10
> msec. Most modern rigs have that delay built in -- they delay RF output
> by approximately that amount after the DC keying signal for the amp.
> Dunno about the Pro III in that regard. My Titans are fine with TS850,
> FT1000MP, K2, and K3, even doing full QSK. I don't run QSK much
> anymore, because I do lots of contesting and would have to replace
> relays every few years. I've gotten lazy in my old age.
>
> 73, Jim K9YC
>
>
>
> ------------------------------
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> End of Amps Digest, Vol 101, Issue 39
> *************************************
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|