[NLRS] Question on TE 1410G amplifier

[Dr. Gerald N. Johnson]

It could be a degraded final. I have a Mirage that I drove RF into a 
shorted coax cable and it draws lots of current without drive. I presume 
shorted transistors.

You might check to see if the bias adjustment has wandered to set the 
idling current high.

I see from the manual
ftp://rrcs-24-73-224-186.se.biz.rr.com/pub/Amateur/1410-1410G/Operating%20and%20Service%20manual.pdf
that the bias was set by selecting resistors at assembly and isn't 
discussed. It calls for 20 amps nominal and 26 amps peak.
A bad transistor can cut the power and raise the current, as can too 
much forward bias. Maybe you can kill the forward bias to see if that 
drops the idling current to zero. In bipolar transistors that should 
always be the case unless the transistor has been partly melted.

73, Jerry, K0CQ


On 12/6/2015 7:59 PM, Jon Platt via NLRS wrote:
>
>
>
> I have a TE 1410G 2m amplifier.  It has been drawing high current.  It delivers about 50 watts out with 20 amps, and with full drive applied about 110 watts output with 35 amps.  13.8 vdc.  I think spec for max output for this amplifier is ~ 160 watts at 25 amps.  I've seen low or no power output with blow finals, but not excessive current like this.  Is it a degrade RF final?  Will a degraded device cause low-ish output with such high current draw?  Original parts are MRF 247, replacement parts are 2SC2782.   Thoughts?
>
> 73, Jon
> W0ZQ
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