Hi Larry,
You have not offered many details as to what you have already checked.
Try checking the following:
1) Model number - Most (if not all) Ten-Tec HF amplifiers model numbers
start with a 4. I have a Titan which is a 425. There have been other
versions of Titans and I thought they were all 4XX model numbers. I'll
bet that was just a typograpical error on your part, and you've really
got a 425.
2) Are the keying loop cables all hooked up correctly and are the cables
good. My 425 had some typed paper lables that fell off. So the keying
loop cables could get mixed up. If you hook them up wrong you might get
the problem you are having. The circuitry is designed to prevent hot
switching and I don't recommend that you defeat it.
3) Drive from the exciter - have you measured it with a wattmeter (or
other power indicator such as a SWR bridge) in the line from the exciter
output to the Titan drive input?
4) What kind of exciter are you using anyway? You're not giving us much
information to work with. If it is not a Ten-Tec transceiver with a
keying loop setup you will need to hook it up according to the manual
for the amplifier which shows interconnections for several kinds of
rigs. If you don't have a complete manual that shows those diagrams I
suggest you proceed no further until you get one.
The RF sensing circuit in the input of the amplifier does not work as
you have suggested, which is sort of like a CB or VHF/ UHF FM amplifier
works using the RF sensing to key the amplifier. The RF sensing circuit
in the Titan ( and other Ten-Tec QSK capable amps) actually is used to
PREVENT the amplifier from keying when there is RF drive without the
proper control signal.
I know all this information from reading the manual. If you cannot read
the manual and figure it out, you may not be qualified to operate an
amplifier. I am not intending to be insulting, however you did not offer
a callsign in your post, so it is natural to suspect you may not have a
ham license.
DE N6KB
Larry Groom wrote:
>My late model Titan amp has had a problem that at first would
>show up seldom, but has now shown up regularly. It will not put
>out power when the exciter is key down. I can hear the Vacuum relay
>keying up, but there is no output. A friend tested the relay over 100 times
>with no failure.
>My question is this... Is it possible to bypass the circuit that senses the
>input RF and then allows the amp to key up? I would like to see if it
>will work when PTT is grounded with the RF sensing circuit bypassed, thus
>eliminating a possible trouble spot. I called Ten-Tec and they said they'd
>be happy to work on it, but that it could be a ton of things including the
>tubes
>etc and I'd like to have an idea of what is wrong if I could. I wish the
>problem
>wasn't intermittant, that would help.
>
>Thanks in advance for any help
>
>73's Larry
>lgroom@frontiernet.net
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>
>
>
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