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Re: [TAIT_Radios] Tait T800 Series II VHF

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  • James Delancy
    That is how I did a 110 watt VHF Mitrek one time. All of a sudden it came to life at almost 200 W and did not self destruct .... Memories! James WJ1D On
    Message 1 of 10 , Jun 12, 2011
      That is how I did a 110 watt VHF Mitrek one time.  All of a sudden it came to life at almost 200 W and did not self destruct .... Memories!

      James WJ1D


      On 6/12/2011 6:56 PM, Steffen Wiest wrote:

      I have the alignment, but I could not find the test point that it talks about to align the vco. I did it the plow boy way, turned it until it locked then aligned the front end...

      On Jun 12, 2011 5:36 PM, "mike-g7bnf" <g7bnf@...> wrote:
      > Yep I'd go with the vco
      > Esp if you did not reset it when you pulled the
      > freq to hamband
      >
      > mike
      >
      > -----Original Message-----
      > From: TAIT_Radios@yahoogroups.com
      > [mailto:TAIT_Radios@yahoogroups.com] On Behalf Of
      > James Delancy
      > Sent: 12 June 2011 23:21
      > To: TAIT_Radios@yahoogroups.com
      > Subject: Re: [TAIT_Radios] Tait T800 Series II VHF
      >
      > I have seen high pitched whine in several
      > circumstances.
      >
      > 1) When a VCO is on edge of "going out of
      > lock" or is just plain going "south"
      >
      > 2) When one of my R1225 Motorola UHF
      > repeaters was getting slammed with a line of sight
      > condition to a UHF TV station at 1 megawatt ERP or
      > so (thank GOD for the DTV transition!).
      >
      > 3) When audio has an imbalance or the chassis
      > of all equipment is not correctly common bonded.
      >
      > 4) When too much of my own RF got back into
      > the cabinet ... often related to #3.
      >
      > 5) I am sure there is more ... just not in
      > the front of the brain right now.
      >
      > Now mind you, I have worked on all kinds of
      > repeaters, mostly Motorola ... but never Tait
      > (yet). This is what I have come across on several
      > occasions. Since you had this happening on the
      > bench and on site, did you try keying the Tait
      > with no other equipment attached to it? Is it a
      > standalone repeater with its own integral control?
      > If so, I would say lean towards #1 or #2
      > (secondarily if the repeater is not isolated into
      > a dummy load on double shield cable). Also, I am
      > not sure about this, but I think that T800 is a
      > modular design whereas the different major
      > components are on their own cards in the chassis
      > ... try something simple and clean and re-seat
      > them all! Just be careful not to hot pull
      > anything that does not specifically say that you
      > can hot pull it!
      >
      > Good luck!
      >
      > James WJ1D
      >
      >
      >
      > On 6/12/2011 6:08 PM, JB Gates wrote:
      >> I have a T800 Series II that I have setup as a
      > 2m Amature Repeater, unit works great, its
      > installed in a building with no Air Conditioning
      > and it has been rock solid. Only problem I am
      > having is anytime the Exciter is keyed their is a
      > high pitched whine in the background. I say
      > anytime the excited it keyed because if I force a
      > keyup with the front switch it does it and
      > whenever being used as a repeater it is always
      > their. I noticed this during initial tuning when
      > on the bench power supply and service monitor,
      > still does it on a different power
      > supply...Looking for any assistance. I have a
      > service manual on the Receiver and a pinout/jumper
      > configuation for the backplane and that is it.
      >> Thanks!
      >>
      >>
      >>
      >> ------------------------------------
      >>
      >> Yahoo! Groups Links
      >>
      >>
      >>
      >>
      >
      >
      > ------------------------------------
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
    • Steffen Wiest
      Does anyone know where the vco test point is? I could not find it on the board as described in the alignment manual? I will try bypassing the pa tomorrow. It
      Message 2 of 10 , Jun 12, 2011

        Does anyone know where the vco test point is? I could not find it on the board as described in the alignment manual?
        I will try bypassing the pa tomorrow. It has a high refl power alarm at 103w fwd and 5refl.
        Also thanks all for all of your help.

        On Jun 12, 2011 5:36 PM, "Steve" <steve.m1swb@...> wrote:
        > Put a meter on the vco test point and make sure
        > that it is 9volts
        > ----- Original Message -----
        > From: "JB Gates" <swiest@...>
        > To: <TAIT_Radios@yahoogroups.com>
        > Sent: Sunday, June 12, 2011 11:08 PM
        > Subject: [TAIT_Radios] Tait T800 Series II VHF
        >
        >
        >>I have a T800 Series II that I have setup as a 2m Amature Repeater, unit
        >>works great, its installed in a building with no Air Conditioning and it
        >>has been rock solid. Only problem I am having is anytime the Exciter is
        >>keyed their is a high pitched whine in the background. I say anytime the
        >>excited it keyed because if I force a keyup with the front switch it does
        >>it and whenever being used as a repeater it is always their. I noticed this
        >>during initial tuning when on the bench power supply and service monitor,
        >>still does it on a different power supply...Looking for any assistance. I
        >>have a service manual on the Receiver and a pinout/jumper configuation for
        >>the backplane and that is it.
        >> Thanks!
        >>
        >>
        >>
        >> ------------------------------------
        >>
        >> Yahoo! Groups Links
        >>
        >>
        >>
        >
      • Ed Yoho
        Along the end of the VCO nearest the back of the radio is an inductor (L1). Touch your voltmeter to the left end (nearest the VCO mounting screw). Adjust that
        Message 3 of 10 , Jun 12, 2011
        Along the end of the VCO nearest the back of the radio is an inductor
        (L1). Touch your voltmeter to the left end (nearest the VCO mounting
        screw). Adjust that point for 9 volts.

        Attached is a PDF of the VCO board layout.

        Ed Yoho
        W6YJ


        On 6/12/2011 4:39 PM, Steffen Wiest wrote:
        >
        >
        > Does anyone know where the vco test point is? I could not find it on the
        > board as described in the alignment manual?
        > I will try bypassing the pa tomorrow. It has a high refl power alarm at
        > 103w fwd and 5refl.
        > Also thanks all for all of your help.
        >
        > On Jun 12, 2011 5:36 PM, "Steve" <steve.m1swb@...
        > <mailto:steve.m1swb@...>> wrote:
        > > Put a meter on the vco test point and make sure
        > > that it is 9volts
        > > ----- Original Message -----
        > > From: "JB Gates" <swiest@...
        > <mailto:swiest@...>>
        > > To: <TAIT_Radios@yahoogroups.com <mailto:TAIT_Radios@yahoogroups.com>>
        > > Sent: Sunday, June 12, 2011 11:08 PM
        > > Subject: [TAIT_Radios] Tait T800 Series II VHF
        > >
        > >
        > >>I have a T800 Series II that I have setup as a 2m Amature Repeater, unit
        > >>works great, its installed in a building with no Air Conditioning and it
        > >>has been rock solid. Only problem I am having is anytime the Exciter is
        > >>keyed their is a high pitched whine in the background. I say anytime the
        > >>excited it keyed because if I force a keyup with the front switch it
        > does
        > >>it and whenever being used as a repeater it is always their. I
        > noticed this
        > >>during initial tuning when on the bench power supply and service
        > monitor,
        > >>still does it on a different power supply...Looking for any
        > assistance. I
        > >>have a service manual on the Receiver and a pinout/jumper
        > configuation for
        > >>the backplane and that is it.
        > >> Thanks!
        > >>
        > >>
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