KPA1500 fan mod done - MUCH better

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KPA1500 fan mod done - MUCH better

Dave wo2x
Hi All,

 

Received the new LED board for my KPA1500 power supply. Easy to swap out,
six plugs and two screws. You can move one plug at a time to the new board
so there is no chance of screwing anything up. To put the screws back in I
suggest a Phillips screwdriver with magnetic tip. It took more time to
remove the 16 screws from the top cover than to swap the board.

 

THANK YOU Elecraft!

 

73

Dave wo2x

 

 

 

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Re: KPA1500 fan mod done - MUCH better

k6mrmagnet
You didn’t happen to notice the value of the changed resistor did you?  The fan resistor is the big one.

Ken K6MR

From: [hidden email]<mailto:[hidden email]>
Sent: Thursday, June 4, 2020 17:00
To: [hidden email]<mailto:[hidden email]>
Subject: [Elecraft] KPA1500 fan mod done - MUCH better

Hi All,



Received the new LED board for my KPA1500 power supply. Easy to swap out,
six plugs and two screws. You can move one plug at a time to the new board
so there is no chance of screwing anything up. To put the screws back in I
suggest a Phillips screwdriver with magnetic tip. It took more time to
remove the 16 screws from the top cover than to swap the board.



THANK YOU Elecraft!



73

Dave wo2x







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Re: KPA1500 fan mod done - MUCH better

Eric Norris-2
In reply to this post by Dave wo2x
I had completely forgotten that I did this mod, and the two resistors mod.
That, and the piece of grit or whatever that was stuck in one of the PSU
fans making it scream like a banshee, took the KPA1500 PSU fan noise from
being intolerable to unnoticable.

Good times!  Ain't it grand!

73 Eric WD6DBM

On Thu, Jun 4, 2020, 4:59 PM <[hidden email]> wrote:

> Hi All,
>
>
>
> Received the new LED board for my KPA1500 power supply. Easy to swap out,
> six plugs and two screws. You can move one plug at a time to the new board
> so there is no chance of screwing anything up. To put the screws back in I
> suggest a Phillips screwdriver with magnetic tip. It took more time to
> remove the 16 screws from the top cover than to swap the board.
>
>
>
> THANK YOU Elecraft!
>
>
>
> 73
>
> Dave wo2x
>
>
>
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
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Re: KPA1500 fan mod done - MUCH better

Dave wo2x
Yeah PSU fan noise is on par with the fans in the Flex 6700 now. PC is almost completely silent. Thinking of locating the amp, radio, and 4O3A 2x8 antenna switch in my garage in a half height server cabinet. Then I could hear myself think, but maybe I don’t want to hear myself ;-)

The two chip resistor mod on filter board was fun. I have experience with surface mount rework so no big deal. One resistor was the size of “16” onthe date on a penny (2016).

Other mods - they installed zener diodes tonthe gates on the LDMOS devices to protect against overdrive. That is one thing the LDMOS devices do not like.

Mybamp uses a pair of NXP 1K50H devices which I feel are more rugged than BLF188 and 189s. I heard early amps used the 188s but no proof of that.

Have fun!

73
Dave

Sent from my iPad

> On Jun 5, 2020, at 1:10 AM, Eric Norris <[hidden email]> wrote:
>
> 
> I had completely forgotten that I did this mod, and the two resistors mod.  That, and the piece of grit or whatever that was stuck in one of the PSU fans making it scream like a banshee, took the KPA1500 PSU fan noise from being intolerable to unnoticable.  
>
> Good times!  Ain't it grand!  
>
> 73 Eric WD6DBM
>
>> On Thu, Jun 4, 2020, 4:59 PM <[hidden email]> wrote:
>> Hi All,
>>
>>
>>
>> Received the new LED board for my KPA1500 power supply. Easy to swap out,
>> six plugs and two screws. You can move one plug at a time to the new board
>> so there is no chance of screwing anything up. To put the screws back in I
>> suggest a Phillips screwdriver with magnetic tip. It took more time to
>> remove the 16 screws from the top cover than to swap the board.
>>
>>
>>
>> THANK YOU Elecraft!
>>
>>
>>
>> 73
>>
>> Dave wo2x
>>
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Re: KPA1500 fan mod done - MUCH better

exbpi
Dave,

So, are these mods documented somewhere on the Elecraft site? I have been unable to locate them. Further, I can't even get Elecraft to respond about when they will provide schematics for the KPA1500.

Thanks

Mike
K7PI


-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Dave
Sent: Thursday, June 4, 2020 22:41
To: Eric Norris <[hidden email]>
Cc: elecraft@mailman qth. net <[hidden email]>
Subject: Re: [Elecraft] KPA1500 fan mod done - MUCH better

Yeah PSU fan noise is on par with the fans in the Flex 6700 now. PC is almost completely silent. Thinking of locating the amp, radio, and 4O3A 2x8 antenna switch in my garage in a half height server cabinet. Then I could hear myself think, but maybe I don’t want to hear myself ;-)

The two chip resistor mod on filter board was fun. I have experience with surface mount rework so no big deal. One resistor was the size of “16” onthe date on a penny (2016).

Other mods - they installed zener diodes tonthe gates on the LDMOS devices to protect against overdrive. That is one thing the LDMOS devices do not like.

Mybamp uses a pair of NXP 1K50H devices which I feel are more rugged than BLF188 and 189s. I heard early amps used the 188s but no proof of that.

Have fun!

73
Dave

Sent from my iPad

> On Jun 5, 2020, at 1:10 AM, Eric Norris <[hidden email]> wrote:
>
> 
> I had completely forgotten that I did this mod, and the two resistors mod.  That, and the piece of grit or whatever that was stuck in one of the PSU fans making it scream like a banshee, took the KPA1500 PSU fan noise from being intolerable to unnoticable.  
>
> Good times!  Ain't it grand!  
>
> 73 Eric WD6DBM
>
>> On Thu, Jun 4, 2020, 4:59 PM <[hidden email]> wrote:
>> Hi All,
>>
>>
>>
>> Received the new LED board for my KPA1500 power supply. Easy to swap
>> out, six plugs and two screws. You can move one plug at a time to the
>> new board so there is no chance of screwing anything up. To put the
>> screws back in I suggest a Phillips screwdriver with magnetic tip. It
>> took more time to remove the 16 screws from the top cover than to swap the board.
>>
>>
>>
>> THANK YOU Elecraft!
>>
>>
>>
>> 73
>>
>> Dave wo2x
>>
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net Please help support this
>> email list: http://www.qsl.net/donate.html Message delivered to
>> [hidden email]
______________________________________________________________
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Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]

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