[Amps] KPA1500 Efficiency vs. RF-Kit B26

[John Simmons]

Dave,

Back in the day I DID repair Motorola VHF amps that had that very problem!


-- 
73,
-de John NI0K in rural Debs, MN USA
https://www.qrz.com/db/NI0K

Artek Manuals wrote on 7/13/2021 3:52 PM:
> Yep ....same here with my KPA1500 though I rarely see temps over 70C 
> (Im not as good a contester as K9YC) . 25000 QSO's in the first two 
> years of ownership...I put the Alpha 9500 in the cabinet as a spare 
> and it has never seen the light of days since ..
>
> The fault level according to the manual is 112C
>
> Back in the good old days at Bipolar days at Motorola 2-Way we had PA 
> decks get hot enough the reflow the solder on the PA transistors on 
> the ceramic substrate...8^)
>
> Dave
> NR1DX
>
>
> On 7/13/2021 3:25 PM, jim.thom jim.thom at telus.net wrote:
>> Date: Mon, 12 Jul 2021 01:40:49 -0700
>> From: Jim Brown <jim at audiosystemsgroup.com>
>> To: amps at contesting.com
>> Subject: Re: [Amps] KPA1500 Efficiency vs. RF-Kit B26
>>
>>
>>
>>
>> <When I'm contesting on HF, always at 1.5kW, I've seen temps at 90 C, 
>> the
>> <fans run faster, I'm happy, and the amp is happy.
>> <73, Jim K9YC
>>
>> ## 90 deg C ? wtf?
>> 90 deg C = 194 deg F !
>>
>> ## Are u sure abt this ? That's stupid hor for a LDMOS device. What is
>> the ambient temp in the shack when this is going on ?
>>
>> Jim VE7RF
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>