Hello OM,
Not familiar with the Titan II, but when my Titan 1 425 failed with
the exact same symptoms, the B- bias diode
in the power supply "opened up" and was not supplying bias to the
tubes.. Chances are that diode is "open".
73, Jim W3KA
On 2017-03-21 05:27, kr7o@vhfdx.com wrote:
> I am repairing an amp that was from a friend's estate and have fixed several
> issues, but now when I switch the amp to Operate, considerable heat is coming
> out of the exhaust, so it appears the tube is partially biased on all the
> time. I have loaded the amp many times up to about 1kw output, so I am
> reasonably confident that the tube is OK.
>
> According to the manual, the cutoff voltage is supposed to be -130v, but with
> 70vac on the primary into a half wave bridge, I cannot understand where they
> are getting -130v from. My bias voltage is only -80v in RX. I get up to
> -95v with the bridge unloaded, which is close to what would be expected from
> a half wave bridge. The screen voltage supply appears to be functioning
> normally.
>
> I will admit, I am not much of a tech, but I DO know how to work around high
> voltage and avoid exposed plate voltage unless absolutely necessary. I have
> gotten this far, and would love to get this amp running if anyone has
> experience with this amp and does not mind helping me sort this out. I have
> more history and measurements, but I will spare the list.
>
> Thanks,
>
> 73, Robert KR7O/YB2ARO, DM07ba/OI52ee (ex. N7STU)
> DXCC 6M #1122
> WAZ 6M #112
> VUCC 6M, 2M
>
> www.vhfdx.com [1] (KR7O/YB2ARO pages)
> Looking for old VHF QSL cards and logbooks.
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
Links:
------
[1] http://www.vhfdx.com
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|