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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