Posted by
Jozef Hand-Boniakowski on
Feb 22, 2007; 4:02pm
URL: http://elecraft.85.s1.nabble.com/K1-Front-Panel-Resistance-Issue-tp444102p444104.html
Hello Don and others:
Thank you kindly. This lists collective wisdom appreciated. I will
cease and desist using the analog meter until my DMM arrives. May I
suggest that Elecraft consider upgrading their recommendation about not
using an analog meter to a warning which includes the possibility of
component damage from using an analog meter. I was aware of the
possibility of inaccurate readings, but not of possible damage to
components. I stand educated.
73, Jozef WB2MIC
Don Wilhelm wrote:
> Jozef,
>
> Yes your analog meter CAN be thowing your readings off by that much.
> Do not use an analog meter to do resistance checks on solid state equipment.
> Many make resistance measurements by applying a voltage to the circuit under
> test, and that voltage is high enough to turn on solid state junctions and
> may actually destroy solid state devices.
>
> Measuring voltages and currents with an analog meter may often be OK, but
> definitely NOT resistance measurements.
>
> 73,
> Don W3FPR
>
>
>> -----Original Message-----
>>
>> Hello to the list.
>>
>> This is my first posting on my K1 kit building issues via the Elecraft
>> reflector. Thanks to all in advance. I am awaiting the delivery of a
>> digital multimeter for making resistance/voltage checks, but started
>> construction nonetheless. I have a cheap analog meter, however, and
>> thought that when I get to the resistance check parts I would use it,
>> but not proceed until the DMM gets here.
>>
>> I completed the 4 band filter bard and the front panel (minus the 10
>> turn potentiometer) up to the point where the resistance checks are to
>> be made (page 22), and, here is where my analog meter says that I am way
>> off. The backlight kit was installed, by the way, as per its (somewhat
>> confusing instructions) which then returned me to the page where the
>> resistance checks are made. I get the following big discrepancies:
>>
>> Test pts (+) Resistance Measured
>> DS1 (LCD pins 1-24) >100K around 2K each to ground
>> J1 pin 6 >100K 10K
>> J1 pin 7 >100K 5.8 to 7K (moves up))
>> J1 pin 8 >100K 5.8 to 7K (moves up)
>> J1 pin 10 90-200K 2.3K
>> J1 pin 12 >100K 5.1 to 7K (moves up)
>> J1 pin 15 <50K 28K (yippie!)
>> J1 pin 16 15-18K 9K
>> J1 pin 19 >100K 5.8 to 7K (moves up)
>>
>> Something is definitely awry here. I don't see any bridges, cold
>> joints, nor missed components/joints, incorrectly placed parts.
>> However, with the LCD installed along with the backlit display, there is
>> no way to recheck the pins of the 40 pin MCU from the top of the board,
>> only to look under the socket from the sides. I have rechecked all the
>> component placement and the solder connections 3 times. I cannot find
>> any errors or solder issues. So then, can the analog meter be throwing
>> me that far off? I doubt it. Your expertise is requested in offering
>> advice.
>>
>> 73, Jozef WB2MIC
>>
>>
> --
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