[TenTec] corsair 2 eprom

[A R]

Hi Spencer,

Thanks for the response. Yes, I inspected the soldering and even the foil runs, since Garry at TT told me they had problems with the TT-produced pwb's. The board and soldering are all good, as well as the voltages and the passive components involved. With the processor installed, the voltage at the pin-8 "dit" input is 1.1v., while the voltage at the pin-19 "dah" input is 5v as it should be. With the processor removed the voltage at pin-8 of the socket is 5v, and all other pins check good. All functions of the microprocessor are as they should be, except for the keyer "dit" function. Both of those keyer inputs are hardwired directly to the paddle jack. 
I come out of a background in military and space electronics, where it is standard design practice to never interface an input or output of an LSI device (like the microprocessor) directly to an externally accessible feature, since accidental/inadvertent overstresses at an external feature can cause damage to the costly LSI. Standard design practice in the aforementioned industries, is to insert inexpensive protective "buffer" devices between the outside-world external features and the LSI, which in general are pretty darn intolerant of electrical overstress. Just from the nature of this failure, I'm guessing that the former owner of the Corsair II probably plugged something that he shouldn't have into the keyer jack, and poof........

I'd be happy if I could just defeat the keyer function when in CW mode, and just use a bug or straight key. Unfortunately, the microprocessor program/architecture doesn't accommodate defeating the keyer function.

73,
Allen----W7GIF
  ----- Original Message ----- 
  From: k5gak at powerc.net<mailto:k5gak at powerc.net> 
  To: tentec at contesting.com<mailto:tentec at contesting.com> 
  Sent: Sunday, February 16, 2014 7:37 PM
  Subject: [TenTec] corsair 2 eprom


  I would take a good look at the soldering on the pc
  board.
  Been there on other systems.

  Spencer
   W1GAK

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