From: Garey Barrell 
Subject: Re: [drakelist] TR-7 PIN Diode Update (Was AM Filter Advice for TR-7)


Garey Barrell  made an utterence to the drakelist gang
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Jim -

That diode is used to switch the calibrator in and out.

It "can" cause a problem, especially on the higher bands, if it fails 
shorted.   IF it fails shorted, it puts a .001 uF capacitor to ground at 
the input of the High Pass Filter on the input side of the PA Driver 
stage.  Kinda tends to "roll off" the RF output of the transmitter on 
the higher bands.

If it happens to fail "open", no big deal, the calibrator, which you 
probably haven't used anyway tends to be a little weak.

73, Garey - K4OAH
Atlanta


Jim DiMauro wrote:

>"Jim DiMauro"  made an utterence to
the drakelist gang
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>Hi All:
>
>As some of you may recall, I solved my AM filter problem last week, but then
>I found a bad CR1402 PIN diode (one of the two low power diodes that looks
>like a two-ledgged transistor, mounted on the front HPF board).  I had
>tested the other PIN doides and found all of them to be OK.
>
>The odd thing is that I had no clue that I had a bad diode.  
>  
>
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