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[Amps] Alpha 87a Fault 9

To: amps@contesting.com
Subject: [Amps] Alpha 87a Fault 9
From: George Fremin III <geoiii@kkn.net>
Date: Mon, 29 Oct 2018 15:44:45 +0000
List-post: <mailto:amps@contesting.com>
I have an Alpha 87a that is presenting the following symptoms.

When switching from standby to operate I get a reduction/loss of 
receiver singals. 

When the key line is grounded the amp faults with code 9.

The manual says this about fault 9:

"Transmit PIN diode forward current below minimum require value key down."

I have done a fair amount of searching on the web and I have not 
found anyone describing a fault 9.  K4RO had fault 8 witch is similar 
but it is on "...key up." instead of down. 

I have done some poking around with my volt meter.  

The RX pin diodes seem to be checking OK as far as I can tell 
with them in the curicut per the troubleshooting described here: 

http://www.alpharfsystems.com/wp-content/uploads/2016/05/Alpha_87A_Receive_Loss.pdf

I have also checked some of the voltages as described here: 

http://www.k4ro.net/k4ro/Aplha-87A/TX-PIN-Diode-Replacement.pdf

I have not checked the TX pin diodes yet.  

I will do that later today. 

But would like to hear if anyone has any ideas about fault 9.

Thanks

-- 
George Fremin III - K5TR
geoiii@kkn.net
http://www.kkn.net/~k5tr


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