Re: ALC Problem


Prabhu
 

Dear Paul,
I also suspect RD70HHF1 ..possibly replace with another one and check with dummy load,


Regards


On Sunday, 19 July 2020, Pasquale S via groups.io <iw0hex=yahoo.it@groups.io> wrote:
> Hi Paul, thanks for your answer
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> It’s no a problem related to temperature, RF power goes up slowly, very slowly about 5 seconds to arrive 100 watt !!! This is the first time, then it’s faster.
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> In VHF and UHF there is no problem, so I suppose there is no problem with pre-driver and driver, everything runs well.
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> IN HF/50 I changed RD70HHF1 because I had a fault before; in your opionion, can RD70HHF1 be the problem ???? Vth is about 2 volt, it seems too little value.
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> Regards
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> Pasquale IW0HEX
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> Inviato da Posta per Windows 10
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> Da: Paul
> Inviato: domenica 19 luglio 2020 03:32
> A: ic7000@groups.io
> Oggetto: Re: [ic7000] ALC Problem
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> Hi Pasquale ,
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> In what time frame does it go up? , is it slowly or fast , could it be a temperature related thing as something needs to be warmed up .
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> I think you'd need a oscilloscope to investigate the drama to see where the slow increase is actually happening RF wise like at the pre-driver or driver or even before that as being new finals i doubt if the issue is from there .
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> Also i'd be checking around the power setting dc rail for any variations but the Cro would be far quicker (if you have one) , 73 Paul .
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