[TenTec] Omni C + new Ham = Oops.
paul.r.harker at gmail.com
Tue Oct 15 12:23:20 EDT 2013
Well... here is where I'm at:
Checked the 914 diodes on the SWR board and sensing diode (D1) was bad
(leaky reverse biased). A big smile.
I replaced the offending diode, put everything back together, attached a
dummy load to the output and turned up drive to see how much current was
drawn. I noted a 3 amps input power increase, and smoke. Smile goes away.
Tearing it back down I discover 3.3 ohm R5 and R8 have acquired deep tans.
These couple the impedance matching transformer to the bases of the power
transistors. A subsequent check verifies proper bias voltage to the final
Though toasty brown, and slated for replacement, R5 and R8 are still
Unless I'm missing something major (always a possibility) I'm thinking that
this kinda seals the deal on the power transistors being bad.
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