Re: [Elecraft] K1 DC voltage check

[Don Wilhelm]

"not drastically" was what was used - trying to mean 'very little'.

73,
Don W3FPR

On 2/27/2016 3:12 PM, Mark Petrovic wrote:

Thank you, Don.

What does drastically mean in this context?


On Feb 27, 2016, at 11:59 AM, Don Wilhelm  wrote:

Mark,

You are effectively reading the voltage drop across D16.
That 600mV drop across D16 will not drastically affect the operation of the K1.
If you would like a bit higher voltage on the PA transistor, you can increase 
the voltage of your power supply a bit (the K1 upper voltage spec is 15 volts). 
 If you are running on batteries, it will make a little difference.
If you would like a lower voltage drop across D16, replace it with a 95SQ015 
which is available from Elecraft as p/n E560009 (it is used in the K2 as the 
series reverse voltage protection diode.

73,
Don W3FPR


On 2/27/2016 2:32 PM, Mark Petrovic wrote:
I'm performing the DC voltage checks (page 30 of the instructions), which occur 
immediately after installing the power switch on the RF board.

P1 pin 16 is supposed to be supply minus 300mV, but I get 600mV.  Is this a 
cause for concern?


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] K1 DC voltage check

[Mark Petrovic]

Thank you, Don.

What does drastically mean in this context?

> On Feb 27, 2016, at 11:59 AM, Don Wilhelm  wrote:
> 
> Mark,
> 
> You are effectively reading the voltage drop across D16.
> That 600mV drop across D16 will not drastically affect the operation of the 
> K1.
> If you would like a bit higher voltage on the PA transistor, you can increase 
> the voltage of your power supply a bit (the K1 upper voltage spec is 15 
> volts).  If you are running on batteries, it will make a little difference.
> If you would like a lower voltage drop across D16, replace it with a 95SQ015 
> which is available from Elecraft as p/n E560009 (it is used in the K2 as the 
> series reverse voltage protection diode.
> 
> 73,
> Don W3FPR
> 
>> On 2/27/2016 2:32 PM, Mark Petrovic wrote:
>> I'm performing the DC voltage checks (page 30 of the instructions), which 
>> occur immediately after installing the power switch on the RF board.
>> 
>> P1 pin 16 is supposed to be supply minus 300mV, but I get 600mV.  Is this a 
>> cause for concern?
> 
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] K1 DC voltage check

[Don Wilhelm]

Mark,

You are effectively reading the voltage drop across D16.
That 600mV drop across D16 will not drastically affect the operation of 
the K1.
If you would like a bit higher voltage on the PA transistor, you can 
increase the voltage of your power supply a bit (the K1 upper voltage 
spec is 15 volts).  If you are running on batteries, it will make a 
little difference.
If you would like a lower voltage drop across D16, replace it with a 
95SQ015 which is available from Elecraft as p/n E560009 (it is used in 
the K2 as the series reverse voltage protection diode.


73,
Don W3FPR

On 2/27/2016 2:32 PM, Mark Petrovic wrote:

I'm performing the DC voltage checks (page 30 of the instructions), which occur 
immediately after installing the power switch on the RF board.

P1 pin 16 is supposed to be supply minus 300mV, but I get 600mV.  Is this a 
cause for concern?



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] K1: DC Voltage Check Slightly Off

[Don Wilhelm]

Yes, you should round up to 3.8 volts.  There will be some variability 
due to DMM differences, and some further variability due to component 
tolerances.  When a value like 3.8 is specified, rounding to one 
significant digit is what is intended.


Most of the values listed in the DC voltage charts are the result of 
actual measurement from a properly working unit, so pay attention to the 
conditions listed for any measurements (band, power setting,  supply 
voltage, etc.) - do not use more decimal places than what is listed in 
the chart even though your DMM may show the value to a large number of 
decimal places.  A variation of 10% is usually within the expected 
tolerance range.


73,
Don W3FPR

MGFoster wrote:
I've reached the first DC Voltage Check in the RF Board assembly and 
for the AF amplifier (LM386N-1, component U3) pin 5 check the Voltage 
should be between 3.8V and 4.2V.  My DMM measured 3.786V.  Is this 
significant, or should I just round up to 3.8V?  All other voltage 
check points were within predicted range.

___
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft


Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com