Flex-3000 cycles on and off

  • 1
  • Problem
  • Updated 4 years ago
  • (Edited)
My 3000 has been operating flawlessly since I bought it used about 3 months ago. About 1 month ago it began to crash under PowerSDR 2.7.2 virtually every time I tried to get on the air.

I purchased a number of ferrite filters which I installed on all cables coming out of the Flex as well as an 8 turn RG8X coax cable choke on the output of my Ameritron AL-80. This seemed to work and I had a few qso's with that configuration. Then about 2 weeks ago the radio became SWR sensitive and crashed with a 'High SWR' error with both the 3000 ATU or my LDG AT-1000 either bareback or with the amp.

 Yesterday, the radio quit altogether and went into a mode where it's on for approx. 400 ms and off for approx. 4 sec. One of the relays clicks in step with these times. (maybe the same one that activates when the radio is first turned on)

I measured these times at the output of IC1, a 7805 regulator where the voltage begins correctly at +5VDC for a few seconds, however, and here's where things get a little weird,  when the cycling begins, the 7805 output voltage drops to approx. 1VDC for the 400ms 'on' period and goes back to 5VDC for the 'off' period. Input to the 7805 remains steady at + 13.8VDC.

My first thoughts were that the 7805 was bad, but there's that pesky inverted output voltage to deal with.

What's going on here???  
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Robert AA6UP

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Posted 4 years ago

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Neal - K3NC, Elmer

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Is this with PSDR running or not?
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Robert AA6UP

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It happens with the radio just sitting on the bench. Doesn't make any difference if PSDR is running or not.