[TenTec] TT Centurion AMP failure
jmiller1706 at cfl.rr.com
jmiller1706 at cfl.rr.com
Fri Feb 19 08:02:26 PST 2010
The Centurion is not rated for continuous full power operation for extended periods on RTTY, AM, and some other data modes. Short durations only, or you should reduce your exciter power appropriately. If you were running full power for a long RTTY transmission, you probably saw the plates getting cherry red, but after that there's no telling what you fried.
Jim N4BE
---- tentec-request at contesting.com wrote:
> Send TenTec mailing list submissions to
> tentec at contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/tentec
> or, via email, send a message with subject or body 'help' to
> tentec-request at contesting.com
>
> You can reach the person managing the list at
> tentec-owner at contesting.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of TenTec digest..."
>
>
> Today's Topics:
>
> 1. TT Centurion AMP failure (Doyle)
> 2. Re: TT Centurion AMP failure (KEN RINDFLEISCH)
> 3. Re: TT Centurion AMP failure (Ed)
> 4. Questions about mic input for "Omni C" (Dave Haupt)
> 5. Re: TT Centurion AMP failure (Lyle Dunlap)
> 6. Re: TT Centurion AMP failure (Phil Chambley Sr.)
> 7. Re: TT Centurion AMP failure (Doyle)
> 8. Re: TT Centurion AMP failure (Mike Schatzberg )
> 9. Re: TT Centurion AMP failure (Dr. Gerald N. Johnson)
> 10. Re: TT Centurion AMP failure (Gary Hoffman)
> 11. Re: TT Centurion AMP failure (Phil Chambley Sr.)
> 12. Re: TT Centurion AMP failure (CSM(r) Gary Huber - AB9M)
> 13. Re: TT Centurion AMP failure (Carter)
> 14. herc 444 amp (k8bbm at srt.com)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 17 Feb 2010 16:47:29 -0500
> From: "Doyle" <n4vv at comcast.net>
> Subject: [TenTec] TT Centurion AMP failure
> To: <tentec at contesting.com>
> Message-ID: <DC4F3F90220B4FC38F7DF7124618F85C at KIDS>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Help,
> Was operating RTTY when my Centurion Amp quit working. The symptom is
> that it shows 200 Ma Even in the Stnby position the plate current is 200 Ma
> & the tubes are moderately red. The tubes are only a year old. Any idea
> what might have happened? Looks like a trip a trip to TT.
> Anyone with a Centurion Amp have this symptom?
> Thanks,
>
> Doyle/N4VV
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 17 Feb 2010 14:52:11 -0700
> From: KEN RINDFLEISCH <rindfleisch457 at msn.com>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Message-ID: <SNT121-W2ABF41CDF891F477D0B309C480 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> You need new 3-500 s.
>
> > From: n4vv at comcast.net
> > To: tentec at contesting.com
> > Date: Wed, 17 Feb 2010 16:47:29 -0500
> > Subject: [TenTec] TT Centurion AMP failure
> >
> > Help,
> > Was operating RTTY when my Centurion Amp quit working. The symptom is
> > that it shows 200 Ma Even in the Stnby position the plate current is 200 Ma
> > & the tubes are moderately red. The tubes are only a year old. Any idea
> > what might have happened? Looks like a trip a trip to TT.
> > Anyone with a Centurion Amp have this symptom?
> > Thanks,
> >
> > Doyle/N4VV
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 17 Feb 2010 17:05:18 -0500
> From: Ed <w3nr at comcast.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Message-ID: <4B7C681E.9090004 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Doyle wrote:
> > Help,
> > Was operating RTTY when my Centurion Amp quit working. The symptom is
> > that it shows 200 Ma Even in the Stnby position the plate current is 200 Ma
> > & the tubes are moderately red. The tubes are only a year old. Any idea
> > what might have happened? Looks like a trip a trip to TT.
> > Anyone with a Centurion Amp have this symptom?
> > Thanks,
> >
> > Doyle/N4VV
>
> Was there any snap,crackle or pop ??
>
> I would take a look at how TT provides cutoff bias. Usually its a zener
> in the B-/filament center tap. I would also take a look at the meter
> shunt resistor.
>
> My last choice would be to run out and buy new tubes.
>
> Ed W3NR
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 17 Feb 2010 14:14:33 -0800 (PST)
> From: Dave Haupt <w8nf at yahoo.com>
> Subject: [TenTec] Questions about mic input for "Omni C"
> To: tentec at contesting.com
> Message-ID: <646431.69829.qm at web53502.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> Gents, I have a modest challenge in front of me. I'm to supply an audio processor to be used with a rig that I won't get my hands on until hours before it has to all work. So, I need to "get it right".
>
> The rig, I'm told, is a "Ten-Tec Omni C". Going through the archives here, I think that means it's an "Omni D, Series C", as there seems to have been no such animal as an "Omni C".
>
> The closest thing to a manual I've found is that of an Omni D, model #546. In that manual, the only stated requirement for the microphone is "high impedance". Usually, this means relatively high output voltage...in other words, the 5 millivolts from a Heil HC-5 won't drive the rig well at all.
>
> Looking at the schematic, the mic input Z is evidently set by a 1 Megohm resistor feeding the input of what's nothing more than a two-stage preamp made of a dual 741 op amp. Overall stage gain is about 26dB, and the second stage will begin clipping with mic levels of about 150mV peak. That's quite a bit lower than many high-Z mics, like the EV638. Mind you, I've not got my hands on a rig to measure - this is all based on a quickie SPICE analysis I performed on the circuit involved.
>
> Can someone who owns one of these rigs place an oscilloscope directly on the microphone lead and read out what the actual audio voltage is during normal operations? That would be exceptionally useful.
>
> The pinning of the quarter-inch connector seems straight-up traditional: tip is PTT, ring is MIC, sleeve is GND.
>
> Also from the aforementioned manual, page 2-7:
>
> "Since the crystal ladder filter system is common to both the receiver and transmitter circuits, any audio signal picked up by the microphone while receiving may be applied to the system and appear in the audio output. Acoustic feedback may occur and cause a sustained howl. To completely eliminate any microphone pickup, it is recommended that a SPDT switch be used for the PTT function in the microphone, and that the microphone signal lead by shorted to ground during receive."
>
> Would those of you who own and operate this model agree with the statement? This will make some of my external switching ever so slightly more complex.
>
> Thanks and 73,
>
> Dave W8NF
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 17 Feb 2010 16:18:40 -0600
> From: "Lyle Dunlap" <qskqrq at grics.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <F51857EE27D149C2896EDBF8212D4782 at your4dacd0ea75>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Sounds more like a bias problem to me, if in the stby position you still
> have HV on the plates.
>
> Lyle
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 17 Feb 2010 17:35:56 -0500
> From: "Phil Chambley Sr." <k4dpk at comcast.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <D0FB57A8BD634E13A15134641CC025C6 at sparky>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Doyle....
>
> You almost certainly have a grid to cathode short in one of the tubes.
> Remove them one at a time and see what happens.
>
> Phil C. Sr.
> k4dpk
>
> ----- Original Message -----
> From: "Doyle" <n4vv at comcast.net>
> To: <tentec at contesting.com>
> Sent: Wednesday, February 17, 2010 4:47 PM
> Subject: [TenTec] TT Centurion AMP failure
>
>
> > Help,
> > Was operating RTTY when my Centurion Amp quit working. The symptom is
> > that it shows 200 Ma Even in the Stnby position the plate current is 200
> > Ma
> > & the tubes are moderately red. The tubes are only a year old. Any idea
> > what might have happened? Looks like a trip a trip to TT.
> > Anyone with a Centurion Amp have this symptom?
> > Thanks,
> >
> > Doyle/N4VV
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
>
>
> ------------------------------
>
> Message: 7
> Date: Wed, 17 Feb 2010 17:55:20 -0500
> From: "Doyle" <n4vv at comcast.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <AEF76FE42D624EB5BD7346B95A429FD1 at KIDS>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Phil,
> Received several responses. I just put in my old set of 3-500 tubes &
> have the same symptoms 200 Ma plate current in both the stnby/operate
> position.
> Only live 40 miles from TT, will take it over the first of the week.
> Thanks for the reply.
>
> Doyle/N4VV
>
> ----- Original Message -----
> From: "Phil Chambley Sr." <k4dpk at comcast.net>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Wednesday, February 17, 2010 5:35 PM
> Subject: Re: [TenTec] TT Centurion AMP failure
>
>
> Doyle....
>
> You almost certainly have a grid to cathode short in one of the tubes.
> Remove them one at a time and see what happens.
>
> Phil C. Sr.
> k4dpk
>
> ----- Original Message -----
> From: "Doyle" <n4vv at comcast.net>
> To: <tentec at contesting.com>
> Sent: Wednesday, February 17, 2010 4:47 PM
> Subject: [TenTec] TT Centurion AMP failure
>
>
> > Help,
> > Was operating RTTY when my Centurion Amp quit working. The symptom is
> > that it shows 200 Ma Even in the Stnby position the plate current is 200
> > Ma
> > & the tubes are moderately red. The tubes are only a year old. Any idea
> > what might have happened? Looks like a trip a trip to TT.
> > Anyone with a Centurion Amp have this symptom?
> > Thanks,
> >
> > Doyle/N4VV
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>
>
> ------------------------------
>
> Message: 8
> Date: Wed, 17 Feb 2010 23:29:57 +0000
> From: "Mike Schatzberg " <wow_chf at hotmail.com>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment " <tentec at contesting.com>
> Message-ID: <COL122-DS1452E428BAF0E52C4D3A1D92480 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-15"
>
> The triodes are a zero bias tube, and 200 mils sounds close for no bias voltage. The amp should still make power, although in the wrong class of service. If it does make power, you have lost your cut off bias voltage and will have to trouble shoot that circuit. If both tubes are glowing about the same color, good chance the bias supply is your problem or your bias voltage switching. 73 and Happy DXing, Mike W2AJI Tryon NC
>
>
> -----Original Message-----
> From: Doyle
> Sent: 2/17/2010 9:47:29 PM
> To: tentec at contesting.com
> Subject: [TenTec] TT Centurion AMP failure
> Help,
> Was operating RTTY when my Centurion Amp quit working. The symptom is
> that it shows 200 Ma Even in the Stnby position the plate current is 200 Ma
> & the tubes are moderately red. The tubes are only a year old. Any idea
> what might have happened? Looks like a trip a trip to TT.
> Anyone with a Centurion Amp have this symptom?
> Thanks,
>
> Doyle/N4VV
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>
> ------------------------------
>
> Message: 9
> Date: Wed, 17 Feb 2010 19:32:28 -0600
> From: "Dr. Gerald N. Johnson" <geraldj at weather.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: tentec at contesting.com
> Message-ID: <1266456748.4315.4.camel at localhost.localdomain>
> Content-Type: text/plain
>
> On Wed, 2010-02-17 at 23:29 +0000, Mike Schatzberg wrote:
> > The triodes are a zero bias tube, and 200 mils sounds close for no bias voltage. The amp should still make power, although in the wrong class of service. If it does make power, you have lost your cut off bias voltage and will have to trouble shoot that circuit. If both tubes are glowing about the same color, good chance the bias supply is your problem or your bias voltage switching. 73 and Happy DXing, Mike W2AJI Tryon NC
> >
> >
> Or the keying line is stuck keyed to transmit. Might be a cable or the
> driver, not the PA.
>
> 73, Jerry, K0CQ
>
>
>
>
> ------------------------------
>
> Message: 10
> Date: Wed, 17 Feb 2010 20:45:24 -0500
> From: "Gary Hoffman" <ghoffman at spacetech.com>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <BD93AA852E334025AE3E1F70100151BA at Master1>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Could be its gone into oscillation and feeding back its own signal as drive.
> That, unfortunately, happens.
>
>
> ----- Original Message -----
> From: "Lyle Dunlap" <qskqrq at grics.net>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Wednesday, February 17, 2010 5:18 PM
> Subject: Re: [TenTec] TT Centurion AMP failure
>
>
> > Sounds more like a bias problem to me, if in the stby position you still
> > have HV on the plates.
> >
> > Lyle
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
>
>
> ------------------------------
>
> Message: 11
> Date: Wed, 17 Feb 2010 20:57:51 -0500
> From: "Phil Chambley Sr." <k4dpk at comcast.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: <geraldj at weather.net>, "Discussion of Ten-Tec Equipment"
> <tentec at contesting.com>
> Message-ID: <AC7FB6FD36C741F7967A5F6F61F8C020 at sparky>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Well, if the keying line is shorted, it should draw the standard quiescent
> current.
>
> Must be something on the QSK/cathode board.
>
> Phil C. Sr.
> k4dpk
>
>
> ----- Original Message -----
> From: "Dr. Gerald N. Johnson" <geraldj at weather.net>
> To: <tentec at contesting.com>
> Sent: Wednesday, February 17, 2010 8:32 PM
> Subject: Re: [TenTec] TT Centurion AMP failure
>
>
> > On Wed, 2010-02-17 at 23:29 +0000, Mike Schatzberg wrote:
> >> The triodes are a zero bias tube, and 200 mils sounds close for no bias
> >> voltage. The amp should still make power, although in the wrong class of
> >> service. If it does make power, you have lost your cut off bias voltage
> >> and will have to trouble shoot that circuit. If both tubes are glowing
> >> about the same color, good chance the bias supply is your problem or your
> >> bias voltage switching. 73 and Happy DXing, Mike W2AJI Tryon NC
> >>
> >>
> > Or the keying line is stuck keyed to transmit. Might be a cable or the
> > driver, not the PA.
> >
> > 73, Jerry, K0CQ
> >
> >
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
>
>
> ------------------------------
>
> Message: 12
> Date: Wed, 17 Feb 2010 20:53:12 -0600
> From: "CSM\(r\) Gary Huber - AB9M" <glhuber at msn.com>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Message-ID: <SNT126-DS210C9679636020B7E9DEC1A6470 at phx.gbl>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Also look at the plate choke to see if its burnt.... but the best thing is
> to call TT with the details. Most likely you'll have to send it back but
> that's most likely the quickest resolution.
>
> Good luck,
>
> Gary - AB9M
>
> --------------------------------------------------
> From: "Ed" <w3nr at comcast.net>
> Sent: Wednesday, February 17, 2010 4:05 PM
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Subject: Re: [TenTec] TT Centurion AMP failure
>
> > Doyle wrote:
> >> Help,
> >> Was operating RTTY when my Centurion Amp quit working. The symptom
> >> is
> >> that it shows 200 Ma Even in the Stnby position the plate current is 200
> >> Ma
> >> & the tubes are moderately red. The tubes are only a year old. Any idea
> >> what might have happened? Looks like a trip a trip to TT.
> >> Anyone with a Centurion Amp have this symptom?
> >> Thanks,
> >>
> >> Doyle/N4VV
> >
> > Was there any snap,crackle or pop ??
> >
> > I would take a look at how TT provides cutoff bias. Usually its a zener
> > in the B-/filament center tap. I would also take a look at the meter
> > shunt resistor.
> >
> > My last choice would be to run out and buy new tubes.
> >
> > Ed W3NR
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
> ------------------------------
>
> Message: 13
> Date: Thu, 18 Feb 2010 08:16:55 -0500
> From: Carter <k8vt at ameritech.net>
> Subject: Re: [TenTec] TT Centurion AMP failure
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Message-ID: <4B7D3DC7.90005 at ameritech.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Doyle wrote:
> > Help, Was operating RTTY when my Centurion Amp quit working. The
> > symptom is that it shows 200 Ma Even in the Stnby position the plate
> > current is 200 Ma & the tubes are moderately red. The tubes are only
> > a year old. Any idea what might have happened? Looks like a trip a
> > trip to TT. Anyone with a Centurion Amp have this symptom? Thanks,
>
> My vote is for the "Filament-AC" board (81537). Not too descriptive a
> name, but this is the board that provides the bias. The clue seems to be
> plate current in the standby position.
>
> You do not mention how old your amp is. This has been a common problem
> and TT has gone through at least two revisions/updates to this board; a
> few years ago, they were up to revision C, so if you have an earlier
> radio, you probably do not have the updated board.
>
> It's OK to take it to TT as you are geographically close (hard to ship
> due to the weight), but this board replacement is easily done at home.
>
> If you do it yourself, PLEASE USE EXTREME CAUTION. DEADLY VOLTAGES INSIDE.
>
> If you are at all uncomfortable working on it yourself, by all means,
> take it to TT.
>
> Good luck and let us know the final outcome.
>
> 73,
> Carter K8VT
>
>
>
> ------------------------------
>
> Message: 14
> Date: Thu, 18 Feb 2010 07:46:01 -0600 (CST)
> From: k8bbm at srt.com
> Subject: [TenTec] herc 444 amp
> To: tentec at contesting.com
> Message-ID:
> <696568424.220111266500761451.JavaMail.root at drucker.srt.com>
> Content-Type: text/plain; charset=utf-8
>
> hi, my good old workhorse died.... the stepping motor died, control board won't let me manually bandswitch....
> other than finding a motor, anybody have suggestions on disabling control circuitry so amp can be manually switched/used?
> thanks
> Dave K8BBM
>
>
> ------------------------------
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
>
> End of TenTec Digest, Vol 86, Issue 21
> **************************************
More information about the TenTec
mailing list