[AMPS] TL-922 Again

[Rich Measures]

>VO1MP  Gus Samuelson
>St. Phillips Newfoundland
>
>
>> >Well after what turned out to be a successful repair
>> >I notice that my TL-922 has now developed an intermittent
>> >IP reading of about 100 mils while idling in the 2000V position
>> >and about 1.5 mils in the 3000 V position .
>> >Out put is not affected and for the first time in along while
>> >the amp with a pair of brand new Eimacs is delivering full power.
>> >If I get an opportunity over the Christmas break I will take the 
>> >covers off again. 
>> >Any suggestions where I should look first problems ?
>> >
>> Is the 922 completely stock?
>> -  thanks
>> 
>> 
>> Rich...
>> 
>> R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  
>
>
>Yep  Rich  .... only mod here is the 10 meter 
>that I did in November 1988 according to my Manual.
>
ok

>In any event  the manual says I SHOULD SEE
>150ma IP  when in LP operate mode or sty mode

 is "sty mode"  standby mode?

>and 200ma IP in HP mode.
>I think now that the thing is operating properly for the first time 
>and I'm not accustomed to seeing it that way ??  

If you have any Ip on standby, 'the thing' is on the verge of a serious 
meltdown.  

>  Still would  like to know why the IP meter occasionally
>does not have any reading in idle  or standby mode as
>suggested by the manual ?

If the Ip meter indicates current in standby mode, odds are that a 
grid/fil. short is taking place.  In a stock TL922, a  grid/fil. short 
applies 0V bias to the tube, which causes Ip to flow during standby *And 
Shorts Out* the +110v supply during standby.  Since the +110v supply is 
powered by a winding on the fil. transformer, unless the amplifier is 
switched off, the (unfused) fil. transformer will be destroyed.   This 
scenario can be avoided by snipping the wire between the coil (+110v) of 
the bias relay (near fan) and the nc bias contact on the relay.  (see 
Circuit Improvements for the TL-922 article on my Web site)

>Oh well if it ain't broke mebbe I shouldn't fix it.
>
€  A stitch in time saves 9,  Gus
>  



Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm