Hi Kelly!
I have owned a Titan 425 for the past year or so. I bought it used from
W3NBC.
I can give you some suggestions.
Does your Titan have a red LED next to the meter labeled "Overdrive"... I
believe only the models with over-current protection of the grids have this.
If so...that is a very good thing. If you accidentally overdrive the grids
the tubes won't go bye-bye on you...at least if you don't keep doing it!
I mention this because one of the symptoms on the Titan when one of the
filter caps opens up is the overdrive light comes on even at low power.
If that happens...check your HV meter reading. Mine sits at 2.4KV but when
a cap opens up it drops to 1.8KV.
The original caps in mine were dated 8843 (43rd week of 1988). I am
convinced that this particular run of caps has a problem. The 1985's might
not but boy they sure are getting on in years.
Attached is a photo of one of the 8843 caps cut open to reveal why the cap
failed in an open circuit mode. I THINK it's the +plus+ terminal that has
dissolved away in the photo. They all failed within a 50-100 hour period.
They all looked the same when opened. The flat foil to the one terminal
was intact...the other...disintegrated except for a 1/2" piece riveted to
the screw connection.
Newark Electronics carries them. Depending on who you get on the phone they
are either $17 or $22 bucks each. I think there are 8 or 10 of them in all.
So figure on as much as $200 to re-do the caps. If they open you'll get an
indication and then you can swap them all out. If they short however...not
sure if the diodes in the PS will take it and that could be a more serious
failure.
If you can afford it now...order them so you have them on hand when the time
comes to change them.
I haven't checked the swr on mine... I'll let you know.
Also...the band switch should click SOLIDLY DETENTED. Any play or wobble
might be the switch wafer assembly nuts loosening up. If that happens the
wiper can be half touching a contact and at 1500W it will fry the wafer.
Replacement wafer alone cost me something like $129..all those silver
contacts add up!
Ten-Tec suggested replacing all the rubber grommets in the fan assembly.
The rubber hardens over time. Mine were still pliable so I left them
alone.
One big thing I did was to double sided foam tape (with only one side
exposed) to the bottoms of each of the feet of the Titan. A LOT of the
noise gets amplified by the wooden desk acting like a soundboard. Any
cushion or vibration dampening pad under the amp will cut the noise down by
at least half or more.
I never had any complaints about the transformer humming mechanically. It
is on a solid concrete floor so maybe the hum doesn't get carried through
the shack as well.
I once asked the Eimac people is it better to leave the amp on all the time
I operate even in standby or turn it on for contacts and off when finished.
They said it was a toss-up. Emission drops off with filament hours
(leaving it on) but inrush current at power up also takes it's toll
(multiple power cycles per day). I leave it on most of the time that I am
listening for DX.
It is a beautiful light-weight amplifier (kilograms...not light-weight in
performance). I love having the PS separate...I can carry either one by
itself but my poor back would give out if I had them both in one box.
Enjoy it! Remember...lethal voltages and 1500W of RF can do nasty things to
human flesh and green vegetation!
73 de Tom K2TA
----- Original Message -----
From: "Kelly Jones" <kjones@sullivan1.com>
To: <tentec@contesting.com>
Sent: Friday, August 22, 2003 11:01 AM
Subject: [TenTec] Titan 425 insight needed
> Hello group,
>
> I recently picked up a Titan 425 and am looking for some insight.
>
> One of the first things that I noticed is that the input SWR is over 2:1
on
> both 20 and 40m. It is near flat on 15. I have not tried 80 or 10 yet,
> nor the WARC bands. Looking at the schematic, I didn't noticed where or
> *if* the Titan uses a tuned input for each band. I'm new to Tentec amps,
> so I'm trying to learn the layout of the Titan. I've always had Henry
amps
> and they all had big ole slugs you could tune for each band. Is there a
> way on the Titan to tune the input for each band? If so, where are the
> things located?
>
> I know this has been beaten to death, but is there a way to quiet the
> fan? While it's not much louder than what I'm used to (Henry fans are
> loud), the Titan fan must be slightly out of balance as it does vibrate
the
> desk a little. I find the vibration more annoying than the noise
> itself. I have cleaned the fan so most of the dust buildup is gone, but
> that didn't seem to help much. I also noticed that it looks like someone
> had put a rubber "cushion" under the bottom of the fan, I'm assuming to
> help reduce the vibration. I've read there are no replacements for the
> fan, so I guess I'm looking for suggestions to quiet it down, unless an
> after market type has been made available.
>
> Would it be wise to replace the transformer with a Peter Dahl? I notice
> the transformer hums a little in idle and *really* hums under full
> load. While the hum isn't too annoying since the PS sits under the desk
> out of the way, I just hate to be in the middle of a contest and have it
go
> belly up. I'm also a little concerned about the filter caps in the
> PS. It's hard to tell, but it looks like the caps have a late 1984
> datestamp on them. Was the Titan amp being made that early? If these
caps
> are indeed nearly 20 yrs old, I guess I should think about replacing them
also.
>
> The one good thing is that the amp had been back to Tentec before I
> purchased it for the 160 drift mod. So at least that problem is taken
care of.
>
> Thanks for any advice/insight/suggestions. Compared to my Henrys (which
> have all been sold), this Titan is such a little thing. I keep thinking
> I'm gonna break it. But so far, so good!
>
> 73
> Kelly - KE9KD
> http://www.dxcentral.com
>
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
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