[Amps] Alpha 87a Fault 9

[George Fremin III]

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 at kkn.net
http://www.kkn.net/~k5tr