[SCCC] Rig problems FT-990

[Dennis Vernacchia]

Jay

Not a clue for the FT-900 but will ask around and forward this to SCCC
to see if someone more familiar with that circuit o. The FT-990

73 Dennis N6KI

On Friday, November 26, 2010, J. Parke Allen <vy1ja at live.ca> wrote:
> Dennis and Rick, The FT-990 locked up on CW so that whenever the CW mode is selected the rig is in the key-down state.  When the keyer is turned off, a steady sidetone is generated and if the Keyer is turned on the sidetone is generating a string of Dahs.  Other modes work well.  I believe that the small card behind the Mic gain control on the front panel has gone bad, and on that card the Keyer chip is defective, most likely due to the very high incidence of static electricity up in the dry of Alert, NU.  The rig failed just after SS CW. I have the schematics but they do not include expected wave forms, voltages, or resistance readings, nor does the associated text explain how the key and keyer circuits work.  I have an outboard keyer, so if necessary, we could remove the keyer chip and feed from the front and rear key jacks bypassing the keyer entirely.  The question is where to do it, and how to protect the keying input circuit so that static damage does not happen further into the rig.   Do either of you know anyone who can help me with this problem.  Any help to get my rig back on the air would be very greatly appreciated. Thanks, J., VY1JA – VY0JA vy1ja at live.ca