[TenTec] Titan II Bias issue

[w3ka at lycos.com]

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 at 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.
> 
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Links:
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[1] http://www.vhfdx.com