Intermittent drop of power output

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Flex6500, Maestro, Windows 10, SSDR 2.3.9  I am experiencing an intermittent random drop of RF power output whilst transmitting on CW. (presume it would be the same on SSB) It typically drops to about one third of the set output power level.  It lasts for a few seconds but always recovers then may do it again or continue to remain at the correct power. It is intermittent and difficult to recreate under test.  I cannot tie it to any specific PA temperature being monitored via FR Stack and there is no input DC voltage level change. This happens on a dummy load as well as external ant and the SWR does not alter when the power drops.  I have confirmed that the power does actually drop using an external power meter and not some kind of meter indication fault.

Unfortunately a Flex service centre would have to spend some dedicated time trying to recreate the problem with the risk of declaring it ok.  I have carried out a factory reset on the rig and the effect happens when either using it with the Maestro or PC.

Any thoughts or suggestions of further tests would be useful.
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Mal G3PDH

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Posted 12 months ago

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Martin Ewing AA6E

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Is it a function of the power level? Do you see the effect if you keep the key down continuously? (On dummy load)
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Mal G3PDH

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Martin, it seems to happen at any power level. I carried out checks with key down at 10w into a dummy load. On first test it dropped down to about 3w after a minute or so and then recovered. A further 4 tests of a few minutes each with the PA temp ranging from 33 to 60 degs it did not occur at all so it is extremely and annoyingly intermittent. Have also tested by reverting to ssdr version 2.2.8 just in case it was anything to do with the power stabilization algorithms in 2.3.9 but it did the same so now back on latest software again. Will continue key down checks but reluctant to send off for repair until it is a more definite repeatable fault.
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WQ2H - Jim Poulette

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Is your external power supply maintaining a minimum of +13.8Vdc? If there's any droop - that could be an issue. Good luck !

73
Jim, WQ2H
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Sergey, R5AU

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Hi Mal !
could you check please power supply before fuse and after fuse (then power drop)with Flex meter  from here http://www.denzone.com/
How looks like transmitted signal quality at time power issue ? 

I wanna to say that on my 6700  power coming down on 10% roughly like  on any others modern solid state PA in case temperature up, i am not care
(Edited)
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Mal G3PDH

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Many thanks for all your suggestions, I will try a different PSU and take a close look at the DC voltage levels but with the voltage adjusted to 14v on RX and 13.7 or 13.8 on TX the drop off happened again in QSO's today. I did not see any voltage issue at the time. Using a GSV3000 psu. Will alsoinvestigate the Flexmeter software.
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Mal G3PDH

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Many thanks for all your suggestions, I will try a different PSU and take a close look at the DC voltage levels but with the voltage adjusted to 14v on RX and 13.7 or 13.8 on TX the drop off happened again in QSO's today. I did not see any voltage issue at the time. Using a GSV3000 psu. Will alsoinvestigate the Flexmeter software.
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Lasse Moell

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Bringing up an old topic!
I see the very same fenomena, whilst transmitting CW with my 6500, power just drops, and the screen on Maestro says so too. Cycling T/R will bring power back, have happened 2 times this mornig. Currently using 20-25 watt o/p as amp is easy to drive. This seem to be related to the new SSDR 2.5.1, not sure if I saw this with the old 2.4.9, but I have had instances earlier but very very unfrequently. The radio/Maestro is wired to router, and keyer is attached to radio. Looking at the Net statistics I can see 3-4 dropped packets (out of millions) but also max latency of >1 second. Not sure if this is related, it could be due to my band changing frequently, as normally is at 10 ms. I may have to revert back to 2.4.9 to see if it goes away, but as Mal said, it is not that common and very hard to track down.