KPA1500 Power Supply Fan Noise

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KPA1500 Power Supply Fan Noise

Stephen Zumbrun
Hello, all and Happy Field Day. Say I just wanted to comment about Elecraft service and the help they provided me to make a mod to my KPA1500. My KPA1500 power supply fan was rather noisy. I had seen discussion on the reflector about this so I contacted Doug at Elecraft service. He ask if I could solder.  I informed him I could and he sent me a new 22 ohm, 3 watt resistor and i swapped it out with the 10 ohm, 3 watt resistor on the LED board of the power supply. I am much pleased with the sound of the power supply fan now after the modification. My amp is an early serial number and the new amps come with the 22 ohm resistor on the LED board. So...if your power supply is a bit noisy you might consider this mod and contact Doug at Elecraft Service. The Elecraft part number of the resistor is E500128. 73, Steve W0SZ.
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Re: KPA1500 Power Supply Fan Noise

exbpi
Hi Steve,

Thanks for the update.

So, this is the LED board on the amp, not the power supply? Guess we don't
know at what serial number the change was made?

Mike
K7PI


-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of STEPHEN R ZUMBRUN
Sent: Saturday, June 27, 2020 16:39
To: [hidden email]
Subject: [Elecraft] KPA1500 Power Supply Fan Noise

Hello, all and Happy Field Day. Say I just wanted to comment about Elecraft
service and the help they provided me to make a mod to my KPA1500. My
KPA1500 power supply fan was rather noisy. I had seen discussion on the
reflector about this so I contacted Doug at Elecraft service. He ask if I
could solder.  I informed him I could and he sent me a new 22 ohm, 3 watt
resistor and i swapped it out with the 10 ohm, 3 watt resistor on the LED
board of the power supply. I am much pleased with the sound of the power
supply fan now after the modification. My amp is an early serial number and
the new amps come with the 22 ohm resistor on the LED board. So...if your
power supply is a bit noisy you might consider this mod and contact Doug at
Elecraft Service. The Elecraft part number of the resistor is E500128. 73,
Steve W0SZ.
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Re: KPA1500 Power Supply Fan Noise

Dave wo2x
It is the LED board in the PS.

Dave wo2x

Sent from my iPad

> On Jun 27, 2020, at 7:55 PM, [hidden email] wrote:
>
> Hi Steve,
>
> Thanks for the update.
>
> So, this is the LED board on the amp, not the power supply? Guess we don't
> know at what serial number the change was made?
>
> Mike
> K7PI
>
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On
> Behalf Of STEPHEN R ZUMBRUN
> Sent: Saturday, June 27, 2020 16:39
> To: [hidden email]
> Subject: [Elecraft] KPA1500 Power Supply Fan Noise
>
> Hello, all and Happy Field Day. Say I just wanted to comment about Elecraft
> service and the help they provided me to make a mod to my KPA1500. My
> KPA1500 power supply fan was rather noisy. I had seen discussion on the
> reflector about this so I contacted Doug at Elecraft service. He ask if I
> could solder.  I informed him I could and he sent me a new 22 ohm, 3 watt
> resistor and i swapped it out with the 10 ohm, 3 watt resistor on the LED
> board of the power supply. I am much pleased with the sound of the power
> supply fan now after the modification. My amp is an early serial number and
> the new amps come with the 22 ohm resistor on the LED board. So...if your
> power supply is a bit noisy you might consider this mod and contact Doug at
> Elecraft Service. The Elecraft part number of the resistor is E500128. 73,
> Steve W0SZ.
> ______________________________________________________________
> 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
> 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 Power Supply Fan Noise

Stephen Zumbrun
As Dave mentioned the LED board is in the power supply. Take off the cover of the power supply and the LED board is small board located on front left side as you look at the amp from the rear. It’s held in place by two small screws. The resistor to change is located bottom of the board as your looking at it from the rear of the amp. The resistor needs to stand off the board a couple of mm.

Your question regarding the SN when this change occurred is a good one. I don’t know the answer. My amp was one of the first with a very low SN. 73

> On Jun 27, 2020, at 6:43 PM, Dave <[hidden email]> wrote:
>
> It is the LED board in the PS.
>
> Dave wo2x
>
> Sent from my iPad
>
>> On Jun 27, 2020, at 7:55 PM, [hidden email] wrote:
>>
>> Hi Steve,
>>
>> Thanks for the update.
>>
>> So, this is the LED board on the amp, not the power supply? Guess we don't
>> know at what serial number the change was made?
>>
>> Mike
>> K7PI
>>
>>
>> -----Original Message-----
>> From: [hidden email] <[hidden email]> On
>> Behalf Of STEPHEN R ZUMBRUN
>> Sent: Saturday, June 27, 2020 16:39
>> To: [hidden email]
>> Subject: [Elecraft] KPA1500 Power Supply Fan Noise
>>
>> Hello, all and Happy Field Day. Say I just wanted to comment about Elecraft
>> service and the help they provided me to make a mod to my KPA1500. My
>> KPA1500 power supply fan was rather noisy. I had seen discussion on the
>> reflector about this so I contacted Doug at Elecraft service. He ask if I
>> could solder.  I informed him I could and he sent me a new 22 ohm, 3 watt
>> resistor and i swapped it out with the 10 ohm, 3 watt resistor on the LED
>> board of the power supply. I am much pleased with the sound of the power
>> supply fan now after the modification. My amp is an early serial number and
>> the new amps come with the 22 ohm resistor on the LED board. So...if your
>> power supply is a bit noisy you might consider this mod and contact Doug at
>> Elecraft Service. The Elecraft part number of the resistor is E500128. 73,
>> Steve W0SZ.
>> ______________________________________________________________
>> 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
>> 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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