INFO 080 --K2/100 in distress

[Howard W. Ashcraft]

My K2/100, serial 4375 has worked flawlessly for several years.  This evening, I fired it up and received an INFO 080 message.  There are a number of symptoms.  First, the K2 works somewhat intermittently.  I tried using in on CW and found that it would operate below 5 watts, but was erratic above that level.  Keying the transmitter above 5 watts would cause a staccato burst of transmission (like a string of dits) regardless of what direction the iambic paddle was keyed.  Using tune, however, did not cause the intermittent operation.  If you turn the unit on, sometimes you get an INFO 080 message, sometimes you do not.  Sometimes it seems to reset itself from transmit to receive.

The U1 voltages on pin 1 and 20 are correct.  However, there should be 6v on pin 2 and it is 0.  U9 and U10 are supposed to have 0.2 and 0.15 volts respectively, but are at ground. Not suprisingly, Z5 shows no sign of life.  Changing bands results in relays clicking, but the voltage drop that should be seen on pin 1 also appears intermittent.  Sometimes I see a voltage drop, sometimes I don't.  I also have the sense that the bands switch more slowly than usual, although this may just be my perception.

Z5 being quiet would obviously hinder I/O, but I am not convinced it is at fault because there is no voltage on the associated U1 pins.  It it seems equally likely that U1 is damaged.

Any suggestions other than swapping out Z5 and U1?  (BTW, all connections are good and complete).

73

Howard W. Ashcraft, Jr. W1WF





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