Hi John!
Up until this point the amplifier operated fine. I put doorknob caps in for
the 80 and 160 load caps. Other than that all was well.
I do have the spare tube.
Unfortunately the bandswitch is complicated. It does the following
functions:1. Selects 10 meter auxiliary coil tap2. Selects 160 meter fixed
tune caps3. Select 80 and 160 meter fixed load caps (3)4. Select 40-10 meter
PI-L output inductance5. Select 8 different band taps
There are 15 rotary contacts and 23 fixed contacts in use. The input is
thankfully a resistive divide networks that need no band changing.
I was on for 42 hours in the ARRL CW DX Contest and this was my only amp. I
made a lot of band changes with it and that might have been the proverbial
straw that broke the amplifiers back. The ring that goes around between the
layers of both the front and the middle bandswitch section had broke and then
jammed between the bandswitch contacts. My first hint of problems was when I
could get no power output on 20 meters. Whether it was a pure mechanical
failure of an "RF oven" failure because of the thin strips of metal on the ring
is a subject of speculation on my part.
The picture that you sent a link to clearly shows the problem there is with
fitting a larger switch in, as it would be bumping into the variable tune
capacitor. Multi-Tech Industries has indicated that they could build a
replacement switch using their Model 86 but it would not fit in the allotted
space. Multi-Tech build the bandswitch for the Titan 417 based on their Model
86 chassis.
W1QJ has a switch salvaged from a defunct Titan II and has been very kind in
providing pictures and analysis. I am hesitant to replace it with a used
switch as I might be inviting another failure.
My thinking right now is to convert it to a 40-10 meter amp using the Model 86
switch and deleting both L2 (40A and 80 and 160 tank coil) and taking out the
C1-B rotors and stators of the tune cap and augmenting 40 meter tuning via a
switched-in doorknob.
Hope springs eternal that a walk down the aisles at Xenia in May will provide a
solution.
Any further insight will be much appreciated.
Greg K8GL
From: "jtml@losalamos.com" <jtml@losalamos.com>
To: amps@contesting.com
Sent: Friday, March 30, 2018 3:14 PM
Subject: Re: [Amps] Titan II bandswitch needed
I looked at my Titan II, and thats an interesting bandswitch (IMHO). Did
RF/HV cause failure or just mechanical fell apart?
One view of the switch can be seen at:
http://hamradiomarket.com/articles/Ten%20Tec%20Titan%20II%20Images/115.jpg
I like the Titan 416 model II since it has a lot of space and can be
modified easily. I don't like it because it used the obsolete 4CX1600A
and it had little protection of the screen PS from an internal tube
fault (anode to screen spark). Mine is going to use a 4CX1500A as soon
as I retire and have time to make the change. All the parts are ready.
I checked an Electroswitch and Centralab ceramic switch that I have and
it wasn't there. I have one more place to look as I came across some
switches at a hamfest or somewhere a year or so ago.
73
John
K5PRO
_______________________________________________
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
|
